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Username Post: Mild mods for a 5.7 1993 Z71 Chevy truck??
Axelrod
Senior Member
Posts 876
02-23-04 07:33 AM - Post#396926    

Gentlemen, I just bought a really nice 1993 Silverado Z71. This is the first truck I've owned and I looked for a long time to find one this nice. It has the 5.7-litre engine with two-unit throttle body fuel injection. It specs out to (I think) 210-hp @ 4,000 rpm, and 300 lbs-ft. torque @ 2,800 rpm. The tranny is the four-speed automatic-overdrive with lockup torque converter. I think the rear-end ratio is a stock 3.73.

The truck is very clean and has never been used for work or for towing. The engine has always had regular oil changes (5k) with Castrol synthetic oil. It has 86k miles.

I had it thoroughly inspected by the Chevrolet dealer before I made the deal. They found some engine fluid leaks, (intake manifold, oil pan, and (1) valve cover). They also said the PCV valve had some carbon build up and recommended a tune up. The electronic diagnostics all checked out. I didn't have a compression check done. The rest of the truck checked out okay with just a couple of drivetrain gaskets and seals needed. The truck runs out very well on the road.

I was thinking that since the oil pan gasket and manifold gasket needs to be replaced, it wouldn't be that great of a stretch to do a cam swap. I don't want to get crazy here, after all it is an 86k mile engine. This is a third vehicle, 99% of my driving will be on the street and very occasionally it will be used for towing.

This is what I was thinking: I'd like to get an improvement in Torque/HP of maybe 10-20%, without a give up in mileage or drivability. Would a mild cam swap, K&N filter system or the equivalent, and a efficient, manifold back, exhaust system get me there?

I'd like to avoid changing the intake manifold and throttle body. I also want to use the stock cast iron exhaust manifolds. I don't want to do any head work, if at all possible. I will do a compression check before beginning any work. I'm not familiar with throttle body systems but I've heard these can be "blueprinted". I also see the throttle body spacers that supposedly shape and speed up air flow. What about the stock electronics for this engine? Can they be reprogrammed or "chipped" or would they even need to be, with the mods I'm thinking about?

IF I were to do a cam swap, I'd pick a "truck" cam, something specifically designed as a replacement for this stock engine. I'm not trying to make a hot rod 4X4 truck, I'd just like to bump it up a bit and see if I could get it close to 275-300HP and maybe 350ft lbs of torque. Perhaps that's unrealistic without head work, exhaust headers and possibly even a new intake manifold, however, I don't want to get that deep into it.

Thanks to all in advance for sharing your knowledge.
Matt
Moderator
Posts 7709
Matt
02-23-04 07:44 AM - Post#396927    

For ideas of mods.. go on the link that is in my signature

OnAllFours
Senior Member
Posts 732
OnAllFours
02-23-04 08:17 AM - Post#396928    

I found what I think to be the perfect budget cam for these trucks. It's the same grind as the Edelbrock Performer cam for carburated engines but has been known to work quite well in TBI 350s and pass the smog test with flying colors. If you go to Autozone and ask for their Melling MTC-1 cam kit, they will hand you a cam and lifter set for $90. This is the exact same cam. They list it as a RV cam for 88-95 TBI 350 trucks.

I've had this cam for about 11,000 miles now without any complaints and the truck has much more power then any stock truck with the same engine. I ran it for a few months with the stock chip without any problems as well. I upgraded the chip to a 'HOT Truck' chip from www.tbichips.com for $39 and I've never looked back. Passed emissions first time and ran cleaner then my friends bone stock 94.

I also have a set of Edelbrock TES headers and a K&N Air Cleaner, and full 3" side exit exhaust with a high flow cat and Flowmaster 3" 40 Series Delta Force muffler and it feels nearly as strong as the vortecs. Turns heads too! I have an Edelbrock Performer Intake sitting in the garage waiting to go on as soon as the weather gets a little warmer. I'd like to find a pair of L98 heads as they are supposed to be the easiest stock replacement heads (easier then vortechs becuase the factory EGR stuff still works-where the vortechs require some custom EGR magic to make it legal).

I'd guess that with the cam, L98 heads, intake, 454 TBI, headers, good flowing exhaust, and a chip it would be possible to make damn near 280 hp.

I've also heard the Crane 2030 cam is a great cam, but VERY expensive compared to my $90 alternative!
92 K1500 Z71 5.7 TPI
01 Olds Alero GL2
-
It takes 42 muscles in face to frown when somebody pisses you off, but only 4 muscles to extend your arm and b*tch slap that Mofo.

Axelrod
Senior Member
Posts 876
02-23-04 10:30 AM - Post#396929    

Thanks Fours, that's just the info I was looking for, real world experience but nothing too wild. A couple of questions, if you don't mind. What is a "454 TBI" ? Are you currently running the stock throttle body? What are the specs on the L98 heads, which engine do they come on?

You mentioned headers but I don't want to run them or deal with the associated problems that are sometimes encountered. Besides, I don't think I would benefit too much at the lower RPM's where this truck will normally operate.

Obviously, cam choices would be limited if I don't want to "open it up" with head changes, or headers. I'd like to know the specs for your cam choice next to the stock cam to see how the power band compares.

I'm interested in seeing how far I can take this engine without doing anything beyond external bolt ons, the exception being a mild cam swap. I just want to realize whatever potential the engine already has.

Quote:

I'd guess that with the cam, L98 heads, intake, 454 TBI, headers, good flowing exhaust, and a chip it would be possible to make damn near 280 hp.




I'd guess it over 300.
someotherguy
Moderator
Posts 25471
someotherguy
02-23-04 10:49 AM - Post#396930    

Quote:

Thanks Fours, that's just the info I was looking for, real world experience but nothing too wild. A couple of questions, if you don't mind. What is a "454 TBI" ? Are you currently running the stock throttle body? What are the specs on the L98 heads, which engine do they come on?




I want to thank all4's too; that's the kind of stuff I'm considering doing with my '92 5.7 TBI and hearing others success stories helps a bunch.

The 454 TBI is just a larger bore TBI unit, so you can flow more air. L98 heads are (to the best of my knowledge) cast iron TPI heads. You know, the tuned port stuff GM had from around 85(?) to the early 90's.. Iroc Z's, Trans-Am's, and the earlier Vette's.

Richard
94 C2500LD / 94 C1500 / 06 300C SRT8
Check out my truck shop projects

OnAllFours
Senior Member
Posts 732
OnAllFours
02-23-04 10:52 AM - Post#396931    

By 454 TBI I meant the throttle body. They have 2" bores instead of the smaller 350 and flow a heck of a lot better. I've been told using them helps quite a bit but you have to bring your intake to a machine shop and have the holes drilled larger.

L98 heads came on the F-Body TPI Commaro I think. They are similar to the Vortec heads but have exhaust cross over so your truck's intake EGR port still works. I think they come in cast iron and aluminum flavor. When I get a pair, I'll opt for the Iron I think because of cost and I just feel better knowing I don't have to worry about alum/iron head gasket problems down the road. Plus I like iron.

Cam specs? Here you go, I should have posted them before!

SAE dur 278/288, .050" dur 204/214, --- .420/.443 lift w/1.5 rockers

I've been told this cam swap is worth 30hp over stock, but I'm not sure about that. I'd love to dyno my truck to see how it pans out..but i'm waiting until after the intake swap to do that.

Summit sells the same cam under their house brand, part # SUM-G5000, I think.

As far as the headers, According to edelbrock their TES kit is supposed to help the entire torque curve. They are extremely quiet unlike many cheepo headers and come with a perfect matching Y pipe. It uses donughts for gaskets unlike those crappy collector gaskets that leak every 6 weeks. They also have the hot air riser and O2 sensor bung.
92 K1500 Z71 5.7 TPI
01 Olds Alero GL2
-
It takes 42 muscles in face to frown when somebody pisses you off, but only 4 muscles to extend your arm and b*tch slap that Mofo.

someotherguy
Moderator
Posts 25471
someotherguy
02-23-04 10:54 AM - Post#396932    

Quote:

L98 heads came on the F-Body TPI Commaro I think. They are similar to the Vortec heads but have exhaust cross over so your truck's intake EGR port still works. I think they come in cast iron and aluminum flavor. When I get a pair, I'll opt for the Iron I think because of cost and I just feel better knowing I don't have to worry about alum/iron head gasket problems down the road. Plus I like iron.



While I was researching the Vortec vs. L98 head deal a few weeks ago, I found something that put the iron heads in a better light than the aluminum ones.. dangit I wish I could remember what it was. Maybe it was valve size or.. ?! Wish I had saved that thread; it was information that I dug through a lot of searching to find.

Richard
94 C2500LD / 94 C1500 / 06 300C SRT8
Check out my truck shop projects

OnAllFours
Senior Member
Posts 732
OnAllFours
02-23-04 10:59 AM - Post#396933    

My guess is rocker studs! I know they love to pull out if abused enough, and I'm sure the studs come out of the aluminum quicker then iron because aluminum expands in heat 4 times faster then the steel stud, I think.

Plus I've seen complete runnable pairs of the iron heads on EBay for $250!

Even with my stock smog TBI heads and intake, I can fry my 285s ATs all the way up the ally behind my house. My buddies stock 94 with 265s can barely peal out at all! Of course my truck is a 5 speed so it's a bit easier to get the tires spinning.
92 K1500 Z71 5.7 TPI
01 Olds Alero GL2
-
It takes 42 muscles in face to frown when somebody pisses you off, but only 4 muscles to extend your arm and b*tch slap that Mofo.

Yarmer
Member
Posts 58
02-23-04 08:24 PM - Post#396934    

I don't mean to high jack your post Axle but you said the dealership said your pan gasket was leaking. If you don't mind me asking is it just kind of sweating where there is just a little oil around the gasket or is it actually draining down the side of the pan. Mine is just barely sweating where you can see a film of oil then dirt stuck to it about a 1/2" above and below the gasket. Just wondering because I am curious if I should change my gasket or just leave it alone.
Big_Paul
Old as Dirt Member
Posts 7306
Big_Paul
02-23-04 08:44 PM - Post#396935    

Hey Axle, welcome to CT, stick around you'll love it here!

TBI engines are great to throw some modifications at. They are fairly simple setups that "old school" rodders can understand, even if fuel injection intimidates you. Just think of the TBI as a fancy carburetor. With your normal tools and a paper clip or a real code reader you can work on the truck easier then you think.

Holley and Edelbrock both make TBI intake manifolds. There are plenty of smog friendly headers for your truck as well. An opened exhaust, a set of headers, intake manifold and a custom chip would probably make you happy. A cam would make it even better.

If you are really considering a new cam, also consider headers. I really wouldn't run stock manifolds with the cam, not that you can't. But to get the best out of what you have the headers will really help the cam and vice versa.

It's all in the combination, right gears, right CR, right cam etc... Will get the best out of your $$$ and what you want.

This is a great site with info about the TBI setup, it's a good read if you want to understand what you have a little better. If you pull off a TBI and look at it, it's very simple. The computer handles everything, with a couple of links along the way (mostly just some simple sensors). Here is the link: http://www.goingfaster.com/spo/tbi.html
'96 C-1500 305
'00 Monte Carlo SS
'02 Silverado 2500 HD
------------------------

Badss350
Senior Member
Posts 693
Badss350
02-23-04 08:55 PM - Post#396936    

Hey Onallfours...I was looking a that cam myself after you posted a while back...How does it sound with that cam? Any lump or ping to it? I have the chevy "RV" cam now..has a slight lope to it, not much, but you can tell its not a smooth stock idle...Im wanting something that hits a little more though...I have NO idea what the specs on my cam is...but do have it on sound file...would love to hear yours if posible...but any info on how it sounds would be nice as well...

Thanks,

Jimmy
Distant Thunder Cold As Stone A V-8 Screams Down From Its Throne One By One Each Car Succumbs When Something CHEVY This Way Comes

OnAllFours
Senior Member
Posts 732
OnAllFours
02-24-04 03:06 AM - Post#396937    

HEH, I think it sounds pretty cool. When it's hot outside and the engine idles down quicker before fully warmed up, it's idle is pretty good lope to it. I like it! Once it warms up, the idle has a _slight_ lope but nothing rough about it at all. I can barely feel it in my shifter when sitting at a light. It makes all my friends grin to hear an EFI motor with a cammy sound to it.

I don't have a sound on file, but I really should make one! It sounds pretty bad-ass with the full 3" exhaust and the Flowmaster Delta Force Race 40 Series a friend gave me from a drag car.

92 K1500 Z71 5.7 TPI
01 Olds Alero GL2
-
It takes 42 muscles in face to frown when somebody pisses you off, but only 4 muscles to extend your arm and b*tch slap that Mofo.

Axelrod
Senior Member
Posts 876
02-24-04 09:33 AM - Post#396938    

Quote:

I don't mean to high jack your post Axle but you said the dealership said your pan gasket was leaking. If you don't mind me asking is it just kind of sweating where there is just a little oil around the gasket or is it actually draining down the side of the pan. Mine is just barely sweating where you can see a film of oil then dirt stuck to it about a 1/2" above and below the gasket. Just wondering because I am curious if I should change my gasket or just leave it alone.




I'm not sure, Yarmer. I'm picking the truck up tomorrow. I'll take a look and report back if you want me to. My plan is to clean up the engine compartment real good and then see if I can determine whether there is actually a pan leak, or if oil is just running down the back of the engine and onto the seam between the pan and block. The intake manifold has a leak at the rear, as does one of the valve covers, so it's possible that the oil is traveling to the pan. Time will tell. The dealer has it pegged at 3hrs labor plus $57.00 for the gasket.

The first thing I'm going to change is the tires, currently P265 75R16 Goodyear Wrangler RT/S, which have about 20% tread wear left. I'm thinking maybe increasing to the next larger size or two but will remain with the stock rims. Have read good things about the Bridgestone Dueler AT Revo, a bit expensive but everyone that has them seems to love them. I like the looks and tread pattern too.

I want to drive the truck for awhile to get a baseline feel and some mileage data. Then I'd like to chassis dyno it and go from there. I'll probably start with just an airfilter system, a CFM Tech TBI spacer, complete tune-up including new wires and a hi-flow cat and exhaust system, thinking SS Dynamax Ultra-flow or Borla. If it turns out I have a pan leak and the manifold, pan and valve covers are coming off, I'll give serious consideration to doing a cam swap. I'm already sure the intake IS leaking, so it's going to have to come off. If I decide to do something with the TBI that would be the time to do it. The stock unit is probably a weak link to any additional mods if I ever decided to go further.

I found out the stock TBI unit flows about 450 CFM. I wouldn't think 450 CFM would support a cam change, seems like it would run out fairly quick. Of course, head flow is a limiting factor too. A bored 350 TBI can flow 630 CFM. A stock 454 TBI flows 670 CFM. I would need to raise fuel pressure to match air flow if I used a bored unit or the larger 454 TBI unit.

Like I said earlier, I don't want a hot rod 4x4, just a sweet running truck with a bit more punch. I don't want to give up any low end torque for high end power. I know headers are a high return for the buck item but I think most of the HP they'd bring would be at a higher rpm. I might even suffer a loss of low end torque. I prefer to stay with cast manifolds. Same goes for the stock heads, although L98's might make a nice upgrade down the road.

Thanks for the link Big John.

Impalaman1966
Senior Member
Posts 6228
02-24-04 10:19 AM - Post#396939    

i have a 93 2wd pickup, 5.7 with the 4L60E trans. it has an edelbrock performer tbi intake, flowmaster cat back exhaust with jba shorty headers, k&n filter, removed the silencer from the air filter, and a jet chip. i also run mobil 1 5w30, with a quart of lucas oil booster, and lucas semi synth atf in the trans. the result is its fairly peppy, and i can baby it to about 15 mpg around town. i had 3 piece underdrive pulleys which made a big difference in the seat of the pants, but it didnt charge the battery well enough in traffic with the a/c or heater on. also had a vortech blower once, put the truck in the low 14's in the quarter mile, but premium fuel made that a pain, also the stock throttle body wouldnt hold the 6 psi of boost, so it sprayed gas out of the throttle shaft onto the engine. we've had the discussion before about the TBI spacers, with no real answers. there is also a spacer that moves the injectors higher above the throttle body...no clear answer there either. i highly suggest checking the timing...mine was off about 1 degree, big difference. good luck, keep us all posted.

superman311
Member
Posts 42
superman311
02-24-04 06:14 PM - Post#396940    

would i be able to put that cam in a 96 tahoe wiht the 5.7 vortech? and what are some mods that can be done to that mototr?

superman
superman. 2000 cavalier.

InfernoSRT8
Senior Member
Posts 863
02-24-04 06:59 PM - Post#396941    

To the last gentleman who asked, in theory if you wanted a crappy old flat tappet cam in your motor you could remove all the roller hardware, and do it, but thats a step backwards. A good mild Vortec grind is either the LT1 F body car cam, the Impala SS or Caprice LT1 cam or the GM Ramjet cam. Anyhow onto the original question. The power gains you desire are high for even a highly modded TBI motor let along one breathing through the wheezing stock heads and intake. I had( well still have fighting for insurance money on it still) a 92 chev reg cab long box 4X4 (350/700r4/373) riding on 245/75/16 tires and I used it for towing. I had an Edelbrock TBI performer manifold, Edelbrock TES headers hooked into 2.25 dual exhaust( no cats, I love Alberta) just Accel cap and rotor, Rapidfire plugs, an adjustable fuel pressure regulator, timing at 8 degrees of advance and Hypertech chip( don't ever buy ANY off the shelf chip, I started into the DIY chip burning thing and off the shelf chips are just as generic as the original in the truck). With just a shift kit in the 700R I could take every 350 vortec truck and grab rubber in second gear ( yes it was more than one and in multiple configurations) and could do what I wanted well. My next step was a set of L98 iron heads( every TPI 350 powered Camaro has these heads, they are better by leaps and bounds than the 193 swirlports on your truck, not as good as Vortecs as their claim to fame is the combustion chamber, however on a TBI application the upgrade will net little as the whole TBI system is the limiting factor, L98's are cheap, easy to find, bolt right on and will support any number a TBI motor can do), with a cam and a 454's TBI base to compliment my already installed 65 pph injectors from a 9C1 cop car. Now you have to realize off the get go TBI can only go so far, I have never seen a real dyno sheet for a TBI 350 thats over or even at 300 hp because you are dealing with a slow limiting computer and limiting fuel system. If you are swapping the cam at least do an intake and headers, otherwise your gains will be limited. With basically following my path you could possibly near 280 hp and 350 ft lbs or so with a good aftermarket custom tuned chip( outfits like Westers or Turbocity and so forth do that all the time). For maybe a more in depth look at TBI check out www.thirdgen.org, there is some BS on that site but there is really good info hidden in there. I can give on example I know of thats supposedly got power with the stock manifolds and heads and intake. A gentleman at another site who is a tuner at a shop has just a TBI spacer, Magnaflow 3" single, custom ship and a Crane roller cam(.427/.454) lift and he supposedly makes just a shade over 200 hp and 300 ft lbs of torque at the rear wheels, whether that is true or not is debatele, seems very high for the setup and over the internet how can you verify. Oh yeah on that CFM thing you talked about, heres the real deal. All those companies like Holley or even GM say about 670 cfm with a 2" bore TBI, read the fine print. Most of the time this is without the injector pod in place and they are flowed at 3" of mercury versus the standard 1.5" that 4 bbl carbs are rated at. Realistically at 1.5" you are looking at around 500 cfm with a 2" bore TBI, hardly enough to support 300 hp. Plus your stock fuel pump in now inadequate, the injectors are too small unless you crank pressure way up to force fuel through them and so on. You can make decent power, the Crane 2030 is a decent cam, smaller than what I was going to run, but thats because I was trying to push the envelope so to speak. Either way if you can a roller swap is a good upgrade if your block will accept factory roller cam parts( not all do my 92 was not a roller ready block unfortunately) but if yours is then the cams I listed for the Vortec at the top are decent choices for you as well.
2006 Dodge Charger SRT8
1994 Chev reg cab s/b 2wd
1986 GMC 1/2 ton 4X4 6.2 Diesel

Axelrod
Senior Member
Posts 876
02-25-04 06:18 AM - Post#396942    

I talked to a local fuel injection shop, (they do conversions for muscle cars, classic cars, motorhomes, along with rebuilds) they can do a 454 TBI for me but suggested a Holley 670 TBI unit which they use with the GM injector pod on them. They say these will work very well and flow better than the 454ís. I can get a slightly used Holley TBI manifold, which flows much better than the stock manifold and it is already bored out to the 2Ē size, along with the throttle body base and a new chip from them for $375.00. They say the stock ECM will support a cam change but it is best to have a new chip programmed to provide better performance. The 454 TBI would cost me more.

You're right about the 'wheezing' stock heads. I know heads are VERY important and that what I have will limit any results I might get. I should probably look into a set of L98 heads. With mild pocket porting and polishing and a multi angle valve job they should be good for at least 25HP, guesstimate. I just didn't want to go deep into the mods with a 80K+ mile engine. If I were doing a complete rebuild then that would be a different story. The lower end is solid though and should be okay with fresh heads.

I should restate my goals here, just to clarify what I'd like to achieve. 10-20% improvement over stock. That would put me around 230/330 to 250/360 HP/Torque.

If I could get it to 300HP and still maintain a usable torque curve that would be great. Probably not a doable situation with stock heads. My HP desires are quoted as at the flywheel, not rear wheels. I wonder what the drivetrain give up is for a 4X4, running on 2X.

I don't want to run headers. Maybe the cast iron exhaust manifolds from the L98's would be an improvement?

I'd like to get all the specs for this stock engine to run a desk top dyno simulation and then see what mods would give the best bang for the buck without getting crazy. Can anyone help with this here on the site?

Bottom line: This is a truck. I don't want a hot rod 4x4, just a super clean, OEM appearing, better than stock running and sounding rig, that I can drive anywhere and that can tow occasionally if needed.
89socal1500
Member
Posts 3
02-25-04 10:06 AM - Post#396943    

Great info all! I have a dying 305 and this gives me a lot of good ideas for which direction to go when it dies.
Doug Fitz 89 Silverado 1500 - 305 auto/2wd/longbed

MikeJ
Moderator
Posts 4173
MikeJ
02-25-04 10:15 AM - Post#396944    

Is why I made it sticky. Best thread on improvements I've seen in a while.
Mike


Axelrod
Senior Member
Posts 876
02-25-04 12:21 PM - Post#396945    

Quote:

Is why I made it sticky. Best thread on improvements I've seen in a while.




It was my first post too. Good info here from some knowledgable folks. I'm going to take this slow because I want to do it right. This is an unmolested well-cared for truck with alot of potential.

First thing to do is gather some baseline numbers, MPG, chassis dyno, etc. Then a complete tune-up, cold air induction system, and exhaust.

I've got to fix the intake leak, so I may pick up the Holley intake and modified Holley TBI along with a modified chip, at $375 it seems like a good bang for the buck. The Holley TBI and intake should support any cam and head changes I would make, if any, down the road. I do need to find out whether the Holley setup would be too much for the stock heads and cam to handle. If it turns out I do have a pan gasket leak then I'm going to give some serious consideration to a mild cam swap. Going that far, I guess I'd have to consider heads. I'll keep everyone posted.




Trucknut
Senior Member
Posts 3029
Trucknut
02-29-04 07:24 AM - Post#396946    

Excellent thread; the best thread on TBI performance to date in here.

I see where there can be some gains in real world HP and torque, so the next question is cost. Also, there has been no mention of the Vortec heads in here, which BTW work very well with the GMPP TBI-Vortec conversion manifold.

Is it cheaper to go with the F-body heads, chip, cam, 454 TBI or would it be cheaper to use the Vortec heads and intake? I know when I swapped the 305 Vortec heads onto an 89' that I had, it made a difference of night and day with that engine. It was a dog before. I just ran the intake, heads, and advanced the timing by about 6 degrees and drove it.

I'm not saying which was is best, just curious to see the HP/$$$ ratio.

Kris

InfernoSRT8
Senior Member
Posts 863
02-29-04 03:23 PM - Post#396947    

Well I think the non vortec way is cheaper is you go the full route. If you leave the cam alone maybe not, but I could not do that, the TBI cam is far too small to make the most of the rest of the combo. With a new cam and then of course a chip is in order and even without the 454 TBI base, the vortec heads and specific manifold are more money and will you gain so much extra power from them to make it worth the added parts cost, simply with TBI, no.
2006 Dodge Charger SRT8
1994 Chev reg cab s/b 2wd
1986 GMC 1/2 ton 4X4 6.2 Diesel

Axelrod
Senior Member
Posts 876
03-02-04 06:47 AM - Post#396948    

Okay, For those following this thread I have the following update. I talked to the fuel injection shop last night and sealed the deal. I have an appointment for the middle of March. They are a busy shop!!

The first weak link in the stock setup is the overly restrictive stock intake manifold and throttle body base. Those will get replaced by a Holley intake manifold with 2" bores and a much superior flow design. The stock TBI base will also get replaced, by a Holley 670 TBI unit modified to accept my stock injector pod. This setup will match up well with the stock heads and cam but will also support a larger cam and L98 heads if I decide to go further in the future.

In the '93 and newer TBI units, GM used the same injectors as the '89 cop cars. If my notes are correct, these are rated for 65 or 69lbs pr hr at 13psi, compared to 55lbs pr hr on the stock pre '93 TBI units. My injector units will be cleaned, rebuilt, and flow tested to match. The shop will reprogram my existing chip using an existing program that they have developed in-house for this basic setup. The cost will be $375, plus installation, which I am going to let them handle for me. They will install a fuel pressure gauge and adjustable regulator at an additional charge if I want.

I also asked about throttle body spacers and specifically the CFM-Technologies patented design. They told me theoretically, spacers make sense, especially the CFM-Tech design, but whether they can actually give you an improvement you can feel is questionable. Most people can't feel a 10hp increase, especially in a truck. It takes upwards of twenty horse power before you can "feel it". A vehicle can gain or loose 10hp with changes in barometric pressure. Their approach is to address the most restrictive elements of a system first, which in my case is the intake manifold and TBI base. In other words to spend your money where it will do the most good. Tricks and gimics come later, if at all.

I also plan to do a tune up with a new cap, rotor, plugs, and wires. I will install some type of new, less restrictive air filtration system and am leaning to a Volant cool air intake system. This setup uses a Hi-Flow Velocity Air Box and a high performance cotton filter retaining the factory cool air induction and looks OEM.
Exhaust is next, probably DynoMax Ultraflows. Another thing I plan to do is to install a Transgo shift kit with a complete fluid change.

I'm going to check into a chassis dyno run, "before and after". If it's not overly expensive, I'll get it done and report the results here. In the meantime, I'm driving the truck and gathering the MPG stats, and 'seat of the pants' impressions, etc.

The truck runs well, has adequate power and a torquey feel but it runs out of breath quickly with a red line of 4500 rpm.
InfernoSRT8
Senior Member
Posts 863
03-02-04 02:46 PM - Post#396949    

With the new manifold there is really no need for a spacer, as I am concerned no need for one in general, but I don't want to write another mile long post explaining, you can use the sites search button if you want to see why.

On the injectors check that out for sure, all police injectors have tan and yellow markings on top( if you take the wiring harness off the injector you can see them), this designates 65 pph. If they are orange and black, which I suspect they are, they are 55 pph, like all the other TBI 350 trucks.
2006 Dodge Charger SRT8
1994 Chev reg cab s/b 2wd
1986 GMC 1/2 ton 4X4 6.2 Diesel

loviscosity
Senior Member
Posts 350
loviscosity
03-02-04 03:25 PM - Post#396950    

Quote:

By 454 TBI I meant the throttle body. They have 2" bores instead of the smaller 350 and flow a heck of a lot better. I've been told using them helps quite a bit but you have to bring your intake to a machine shop and have the holes drilled larger.






Guess what guys...they do make a 350 tbi with 2 inch bores. They used them on Mercruiser marine motors. Im not sure what type of injectors are used but i do know that the bores are 2 inches.
Also...i have a 454 tbi on my 92 5.7. I did not bore the intake. I actually took a 350 tbi spacer a tapered it perfectly with a die grinder and then used a dremel tool to polish. It looks really nice a professional. I can definetly feel a huge difference in throttle response and the damn thing hits 5,000 rpms like its nothing. Also the back tires wont stop spinning. Driving in the rain has a new meaning until i get a posi installed. Im also running an edelbrock intake which has 1/16 larger diameter bore than the stock intake.

But in the works now(at my engine builders) is a vortec small block with the vortec tbi intake bored to match the 454 tbi. A 454 tbi has 650 cfm of flow so its being built to match that type of flow. I just hope the computer can keep up.
Good luck on your mods.
CHEVROLET COMES FIRST!..........THEN IT ROLLS OVER AND SMOKES A CIGARETTE!?:p Fuel Infected Baby!!!!

loviscosity
Senior Member
Posts 350
loviscosity
03-02-04 03:38 PM - Post#396951    

Also guys...i see everyones going ape $hit about these L-98s....imo...there junk...very good freind of mine built a 91z71 with a 350. He used the edelbrock TBI cam(the one that comes in the kit)...edelbrock intake and complete rebuild of motor. He also installed the L-98 heads. Hes lucky if he got 50 ponies. I rode in his Z71 and it feels like my 92 back when it was stock. Dont get me wrong it has balls for a 4 dig suspension but nothing to scream about. If he woulda used vortec heads he wouldve been on the right track.

Ive done research on the newer style/vortec heads and theres nothing likem. If your gonna throw some money like 300$ at L-98s then u can just throw an extra 200$ towards that and get brand new complete vortec heads with the larger intake valves from Summitt or Jegs. They are Genuine GM heads to.

A note to remember guys when looking for vortec heads.
There are two main sets of heads.
THe ones with serail #s that end in 059 and ones that end in 062. The 059 have the smaller 1.84 intake and the 062 has the 1.94 intake. THe 059s are generaly used on 305s but will work on 350s as well.
Theres also a set of vortec heads that chevy used on there 3/4 1 ton trucks that are junk. SOmething with the exhaust seat has a serious flow problem and u cant get any power from them. Im sure what the # is but make sure u run a search on your head # before u buy.
Good Luck
CHEVROLET COMES FIRST!..........THEN IT ROLLS OVER AND SMOKES A CIGARETTE!?:p Fuel Infected Baby!!!!

GTO_Ryan
Very Senior Member
Posts 2090
03-02-04 04:19 PM - Post#396952    

Isn't the edelbrock TBI cam kind of lame?

Not saying that the L98s are great or anything but I'm sure that cam isn't helping much.
'69 Pontiac GTO 400ci V8 '92 Chevy Blazer '99 Chevy Silverado 5.3L We need an air strike!

InfernoSRT8
Senior Member
Posts 863
03-02-04 05:52 PM - Post#396953    

Quote:

Also guys...i see everyones going ape $hit about these L-98s....imo...there junk...very good freind of mine built a 91z71 with a 350. He used the edelbrock TBI cam(the one that comes in the kit)...edelbrock intake and complete rebuild of motor. He also installed the L-98 heads. Hes lucky if he got 50 ponies




See your buddy used Edelbrocks garbage and may I repeat that in bold so everyone can see EDELBROCKS TBI CAM IS AN OUTDATED PIECE OF TRASH. You ever look at the lift specs, intake is .398 and exhaust is around .442. Well sure the exhaust lobe is allright, but the intake lobe hinders any potential gain with its puny number. If he would have threw a real cam in, something along a 2030 Cranes lines, or an XE256 Comp, and a chip for it, if he didn't have that done, maybe his truck would have some power. Even your wonderful Vortecs would have disappointing performance with that pathetic cam. The L98's delete the swirl port of the TBI 193's, and while the combustion chamber is not up to that of the Vortec, like mentioned, a TBI motor will never exceed the potential power limit of the L98's.

Mild bowl cleanup and any major port hangups cleaned off and the L98's which can be had dirt cheap, and be rebuilt for probably less than the $200 mark( I can have them done by an excellent reputable shop for $100 a head, Canadian dollars), and work with the cheaper, non vortec intakes, is the best way to go for cost effectiveness. If you want to throw money at heads that will essentially gain you nothing, in this application, have at it.
2006 Dodge Charger SRT8
1994 Chev reg cab s/b 2wd
1986 GMC 1/2 ton 4X4 6.2 Diesel

OnAllFours
Senior Member
Posts 732
OnAllFours
03-03-04 09:13 AM - Post#396954    

As far as TBI upgrades, besides the TBI intake, I think the Edelbrock stuff is a waste of money..._especially_ the cam. It's barely an improvement over stock. I'd bet that was the limiting factor and not the L98 heads.

The 350s in our trucks are almost identical to the Gen 3 350s except for the roller cam. Anyone who has driven a Gen 3 TPI 350 car knows those motors are screamers and pull pretty damn hard. With the TBI setup correctly, a good cam, intake, exhaust, chip, and L98 heads...the truck engines should run pretty good too.

On I side note, I heard molesting the vortec heads and putting bigger valves in them actually can hurt their performance. IMO, GM doesn't spend millions on R & D on a performance head that some Napa machine guy can improve on by swapping valves.
92 K1500 Z71 5.7 TPI
01 Olds Alero GL2
-
It takes 42 muscles in face to frown when somebody pisses you off, but only 4 muscles to extend your arm and b*tch slap that Mofo.

Axelrod
Senior Member
Posts 876
03-04-04 08:34 AM - Post#396955    

I have an appointment for a chassis dyno run next Wednesday the 10th. Three pulls ($75.00) should provide me with good base case data prior to any modifications. I'll keep everyone posted.
shotgun
Member
Posts 89
shotgun
03-05-04 01:55 AM - Post#396956    

Wow, this is a really good thread. I just got my truck, and one of the first things I was wondering about was how to bump the hp up a tad.

Is it feasible to bump hp up to 250 without changing the cam or doing any internal mods? Would a stage 2 chip, K&N air filter, 180 degree thermostat, dual exhaust with stock manifolds be enough for 250hp, without losing torque on the bottom end? I would be willing to change the intake and TBI unit, but only if necessary.
Axelrod
Senior Member
Posts 876
03-05-04 06:20 AM - Post#396957    

Quote:

Wow, this is a really good thread. I just got my truck, and one of the first things I was wondering about was how to bump the hp up a tad.

Is it feasible to bump hp up to 250 without changing the cam or doing any internal mods?

I would be willing to change the intake and TBI unit, but only if necessary.




If your truck is like mine, your asking for a 19% increase in HP at the flywheel to get to 250HP. I think it is doable without internal mods.

According to my FI shop, the most restrictive element on my '93 TBI 350 is the stock TBI base plate and the stock intake manifold. I will be doing a chassis dyno run next Wednesday and will post the base case results here. The following week I'll be visiting my fuel injection shop for the intake and injector mods referred to in my post above, along with a custom chip programmed for my application. I will also be installing some type of aftermarket air filtration system but haven't yet made up my mind which one. An exhaust and complete tune up will finish the picture. I don't want headers, although the concensus on this thread seems to believe that's the way to go. My belief on the headers is that most of the benefit comes at higher rpms and not on the power curve where I want to be. I also don't want the problems that often accompany headers.

Exhaust dynamics are complicated, noise doesn't necessarily mean more power. Too big a bore and too much flow can reduce torque, not good for a truck! The idea is to have a system matched to the application intended. I talked to an exhaust shop here in town about installing a high-flow cat and full exhaust. The owner is very knowledgable and a long term high performance enthusiast, (he owns an 8 second drag car). He didn't feel I would gain much, if anything by changing the cat. He says it is a 3" SS Y pipe and SS 3" in and out for the older pellet style cat. He says the gain can be made on my truck from the cat back. I'm going to his shop tomorrow morning for a detailed inspection and accessment. I won't install the exhaust until after I get the base case dyno runs in.

Stay tuned for real results, before and after, verified on the dyno. This will be fun!
GTO_Ryan
Very Senior Member
Posts 2090
03-07-04 04:20 PM - Post#396958    

Headers are definetly the way to go! Headers can be set up to give you benefits at all sorts of different points in the power band. Crappy headers can be a nightmare though when trying to get them to seal properly.
250 seems like a tall order though... the vortecs of the following year had that HP level with much better heads, port injection, and a roller cam.
'69 Pontiac GTO 400ci V8 '92 Chevy Blazer '99 Chevy Silverado 5.3L We need an air strike!

landyot
Senior Member
Posts 141
03-10-04 05:44 AM - Post#396959    

In response to the aluminum heads vs iron heads,one thing that gets overlooked is that when alum heads heat up,they expand.Because of this there is a slight loss of compresion,which equals a slight hp loss also..though it will probably never be felt by a street driver,those who want every last oz of power from their motors may want to consider this.But,to throw another side into it,,the gain from the weight loss may overcome the compression/hp loss...just don't get em hot!
shrugger
Member
Posts 11
03-11-04 02:48 AM - Post#396960    

Would the holley intake need to be modded to fit the L98 heads?
Or are they a direct bolt up?
Axelrod
Senior Member
Posts 876
03-11-04 07:32 AM - Post#396961    

Quote:

Would the holley intake need to be modded to fit the L98 heads? Or are they a direct bolt up?




Depending on the L98 heads, they are a direct bolt on. Cast iron, F-body heads, casting number, 14101083. This is according to Chevyman69.

Made 5 pulls on the chassis dyno yesterday afternoon at Advanced Chassis Dyno in Sterling Heights. The runs were completed with the stock air cleaner and paper element in place, except for the last run, where the top and the element were removed. That run picked up 1.2HP over the previous best run and actually lost 2.3FT LBS TQ, over the best reading for TQ. Two large fans were placed in front of the radiator. Intake air temp was 65.0 F and absolute barometric pressure was 29.62 in.Hg.

Overall average HP: 151.16 HP @ 3980 RPMs
Overall average TQ: 242.92 FT LBS TQ @ 2760 RPMs


Assuming the engine is actually making the rated numbers at the flywheel, this would indicate a power-train loss of 28% for HP and 19% for TQ. That seems high to me but I don't know what the power-train give up actually is. Even though the test was done in two wheel drive, there is still a loss through the transfer case, the automatic and the rear differential, (the larger the differential, the greater the power loss). Anyway, this will give me a base set of numbers to work with in judging future powertrain improvements I make, which is all I wanted to do. The dyno runs didn't indicate any fuel or electrical problems and showed everything to be working properly. We did get a couple of runs that spiked slightly right before the peak HP, apparently caused by the interaction between the computer and the tranny. You have to try to find the sweet spot, after shifting through the gears, where RPMs can be increased to WOT without causing the tranny to downshift. The runs were completed with the trans engaged in DRIVE. The rev limiter kicked in at 4300 rpms.

They had recently completed a dyno run on a '98 Siverado 2X drive with a 5.7 Vortec. I have listed those numbers below. Obviously, the Vortecs are a big improvement over the older 5.7 TBI motors. Greater improvements can obvously be had in the TBI motors though. This could have been achieved by GM before they changed over to the Vortecs but it probably wasn't pursued due to cost and Vortec engine development on the horizon.

Compare to '98 5.7 Vortec 2 wheel drive

Overall average HP: 220.40 HP @ 4600 RPMs
Overall average TQ: 296.10 FT LBS TQ @ 3300 RPMs


The next test for my truck will be a compression test before the installation of the intake.

The truck goes in Saturday for a new exhaust. Not sure which muffler and tailpipe just yet but it will be a 3" single cat back system. I may go with two 2.5" side exited tail pipes after the muffler and out one side, as stock. That would cost more with two SS tips and gives nothing extra in performance, it's just for looks. I don't want it excessively loud or to hear a drone in the cab when cruising. Since I don't have the experience of listening to a number of differant muffler brands for my application, I'm going to rely on the shop owner to steer me in the right direction. He carries pretty much everything. I was originally thinking a Dynomax Ultraflow but the shop owner told me the straight through design is pretty loud. He recommended a Flowmaster, but I'm not sure which series. He says it has a nice muscle car sound but doesn't drone when cruising.

I'll keep eveyone posted and give my impressions after the muffler is installed.

The next dyno run will come after intake, TBI and chip mods, and tune up, probably late March or early April.

Given what I saw for a pickup in HP with the air filter removed, (not much) I'm way less convinced to spend the $250 bucks for an aftermarket air filtration system. I will admit that a smoother shaped air passage might pick something up, but as I see it, you're paying more for looks than performance with most of these systems.

I can remove the noise reducer in the stock box and keep a good quality clean paper filter installed and put that money to better performance use elsewhere. Volant has a "torque tube" that replaces the box and straightens out the cold air flow to the aircleaner for about $40.00 that might be worthwhile to consider.

Stay tuned for more to come.
Axelrod
Senior Member
Posts 876
03-13-04 07:46 AM - Post#396962    

Quote:

The truck goes in Saturday for a new exhaust. Not sure which muffler and tailpipe just yet but it will be a 3" single cat back system. I may go with two 2.5" side exited tail pipes after the muffler and out one side, as stock. That would cost more with two SS tips and gives nothing extra in performance, it's just for looks. I don't want it excessively loud or to hear a drone in the cab when cruising. Since I don't have the experience of listening to a number of differant muffler brands for my application, I'm going to rely on the shop owner to steer me in the right direction. He carries pretty much everything. I was originally thinking a Dynomax Ultraflow but the shop owner told me the straight through design is pretty loud. He recommended a Flowmaster, but I'm not sure which series. He says it has a nice muscle car sound but doesn't drone when cruising.


I'll keep eveyone posted and give my impressions after the muffler is installed.




Well, I ended up going with a Flowmaster 40 Series Delta Force muffler. 3" in and modified for two 2.5" outlets. Sounds nice and mellow, not at all loud.

Amazingly, my '93 truck still had the original GM muffler and factory exhaust, all in real good shape too. We ended up installing just the Flowmaster muffler with a short length of pipe to make up the difference in length between the 40 series Delta Force and the original muffler. The muffler Flowmaster makes to fit this truck without modification, is quite a bit larger and quieter too. Since the 40 series Delta Force doesn't come with 3" in and two 2.5" outlets, we had to modify the muffler.

Greg, the shop owner, used a band saw to cut one end off a 3" single in, center single out. Next he cut the end off a 2.5 single, one side out. This end was mig welded back onto the case of the 3". Next, another 2.5" outlet pipe was shaped and mig welded to the case, then a torch was used to open it up inside. A hanger was shaped and welded to the muffler in order to use the original locations. We also added two nice SS tips with rolled ends to dress up the tailpipes. Everything was welded up nice and clean, no clamps and out the door for $250. Very happy with the results and saved a few bucks over a complete system. Thanks to Greg at Great Lakes Customs in Mt. Clemons.

Looking at the original muffler, you can see that it is very restrictive. It immediately goes from a 3" inlet tapered down to a 2.5" perferated section that runs almost the length of the muffler. I can't see that there's any appreciable difference in power from the Flowmaster muffler but it sure sounds good, without being obnoxious. I'm almost ready to refuel, so I'll see if it makes any difference in the mileage.

Next will be the intake manifold, TBI mods, tune up, and reprogramming, along with some sort of air filter/intake improvements. Hopefully, the fuel injection shop can get me in next weekend. After that it'll go back on the dyno for another run to document the results.
4x4ChevyVan
Member
Posts 2
03-14-04 08:27 AM - Post#396963    

i have a 80 chevy van 4x4 with a 383 stroker motor and want to go FI with it...but i need to know if a stock tbi unit will hit on my holley intake manifold....where can i find this info...i'm hoping a 454 tbi unit can handle may motor....i have around 375hp-400hp so i also need to find out if tbi will provide enough air and fuel for the motor
thanks
InfernoSRT8
Senior Member
Posts 863
03-14-04 10:51 AM - Post#396964    

Quote:

i'm hoping a 454 tbi unit can handle may motor....i have around 375hp-400hp so i also need to find out if tbi will provide enough air and fuel for the motor
thanks




Good luck, a GM 454 TBI can hardly support a healthy 350, let alone a 400 HP 383 stroker. Either run a TPI, or LT1 based system or something aftermarket. You will never make that motor run right with GM TBI. If you want a TBI system Holley sells their Commander 950 with a 4bbl throttle body of varying injector sizes. So let me say this again, you are wasting you time if you want to use GM TBI, its cheap and easy to find, but will never run that motor properly, you get what you pay for.
2006 Dodge Charger SRT8
1994 Chev reg cab s/b 2wd
1986 GMC 1/2 ton 4X4 6.2 Diesel

BIGJ
Member
Posts 19
03-22-04 04:10 AM - Post#396965    

I know EXACTLY what you're going through. A friend of mine told me about this forum since I had some similar questions. I have the same truck, but a '92. I've spent literally MONTHS figuring out combos. I wanted more power, especially in the towing department. Trust me, don't waste your time with the TBI. You're going to end up spending a bunch of money for a mediocre (at best) solution.

If you intend on keeping the truck for a while then just break down and buy a MPFI kit from Edlebrock. They have a full setup or what they call a "kit". Which doesn't include the intake. However it's setup so you can tap any intake you want to use, but includes pretty much everything else you'll need. You can use their ECM however it's not much better than the stock, just has an upgraded prom and can be fineky if you're going to use a custom cam. I'd upgrade to their Commander 950 ECU which has a completely programmable (via laptop) fuel map.

I've gotten so sick and tired of running into dead end combos I'm ready to just buy the Stealth Ram setup from Holley...and take it with me if I ever get rid of the truck.
Axelrod
Senior Member
Posts 876
03-22-04 08:21 AM - Post#396966    

Quote:

Well, I ended up going with a Flowmaster 40 Series Delta Force muffler. 3" in and modified for two 2.5" outlets. Sounds nice and mellow, not at all loud.

Amazingly, my '93 truck still had the original GM muffler and factory exhaust, all in real good shape too.

Looking at the original muffler, you can see that it is very restrictive. It immediately goes from a 3" inlet tapered down to a 2.5" perferated section that runs almost the length of the muffler. I can't see that there's any appreciable difference in power from the Flowmaster muffler but it sure sounds good, without being obnoxious. I'm almost ready to refuel, so I'll see if it makes any difference in the mileage.

Next will be the intake manifold, TBI mods, tune up, and reprogramming, along with some sort of air filter/intake improvements. Hopefully, the fuel injection shop can get me in next weekend. After that it'll go back on the dyno for another run to document the results.




First tank of gas since the Flowmaster installed: almost 16.5 MPG, nearly 1 MPG better than before. Still waiting on getting the truck in for the new intake and TBI mods. The fuel injection shop had a meet in TN over the weekend to attend and couldn't get me in this last week. Of course, I'll keep everyone posted on the dyno results after the work is completed.
92gmc
Senior Member
Posts 144
92gmc
03-22-04 10:15 PM - Post#396967    

I have a similiar setup - 3" single exhaust, no cat, Flowmaster DF 40' series, and its too loud for me. Too raspy. Then again, things changed when i added a TBICHIPS.COM chip.

Would headers reduce the raspy "ba - ba - ba" upon acceleration? 350 TBI 5spd
1992 GMC K1500 Z71 - 6" lift - 5.7 TBI / 5spd. 1972 Ford Torino - 351 CJ 4V Ram Air - 1 of 16 BC Sheriff

Axelrod
Senior Member
Posts 876
03-23-04 04:25 AM - Post#396968    

Quote:

I have a similiar setup - 3" single exhaust, no cat, Flowmaster DF 40' series, and its too loud for me. Too raspy. Would headers reduce the raspy "ba - ba - ba" upon acceleration? 350 TBI 5spd




I have the factory Y-pipe and cat. Mine is not raspy sounding at all. Not loud and very mellow. I doubt you gain much flow by removing the cat. According to the shop which installed the muffler for me, the factory cat is 3" in, 3" out and is a high flow design. Combined with the muffler it will be quieter. Some guys run just the cat and remove the muffler but that will definately be louder. Headers will not make it quieter but might reduce the gurgle.
92gmc
Senior Member
Posts 144
92gmc
03-28-04 10:45 PM - Post#396969    

Ya the dude who installed the 3" custom system on my K1500 said the cat was plugged (meow) so he removed it. Damn. I know a high flow cat is $$$ costly, but a factory one is x3 more haha.

Actually, I think personally the chip I installed changed the pitch and gargling of the exhaust to raspy. I could be wrong ??
1992 GMC K1500 Z71 - 6" lift - 5.7 TBI / 5spd. 1972 Ford Torino - 351 CJ 4V Ram Air - 1 of 16 BC Sheriff

scrambldcj8
Senior Member
Posts 1672
04-04-04 07:23 PM - Post#396970    

OK OK bringing back the TBI cam questions. Looking for some suggestions. I have heard very good things about the Melling MTC-1 (OnAllFours) and especially it's reasonable price tag. I am considering a cam change on a mostly stock 94 4x4 350TBI with an auto trans and 3.73's....and seriously, about a 3500rpm max (my uasage). Looking to maximize lowend torque (and with that will come better fuel efficiency). I was wondering about a couple of CompCams grinds: #12-231-2 with stats of 206/214 dur and .432/.453 lift on 111 lobe sep angle OR #12-249-4 with stats of 206/212 dur and .434/.444 lifts on 112 lobe sep angle OR #12-230-2 with stats of 206/212 dur and .432/.444 on a 110 lobe sep angle? All fairly similar specs but may offer different results. Would these make good cam choices in an engine that does not run in higher rpm ranges, I would like to cam an engine for the rpm range it will see on a daily basis? Would the MTC-1 be "too big" for an application such as this? It is a vehicle which would benefit greatly from additional torque. Thanks for any suggestions or advice! John
90K4x4
Member
Posts 32
04-10-04 01:13 PM - Post#396971    

hey I wanted to post in on this about TBI camshafts and such!

I tried to run a TBI with an ISKY 270 camshaft and due to the loss of manifold vacuum the cam was causing it would idle extremely poor, it would load up at stop lights, and it would sputter from off idle. Once the engine got up in RPM it made amazing power however.

I since have undergone a transformation to carburator (will post in another forum about it)

Any camshaft change you can do to a TBI that won't change the engine vacuum is a great step in the fast direction, but if you have the idea "bigger is better" in your head then it can cause a nightmare.

I recently purchased a 92 Chevy 1/2 ton 4x4 with a 305 however, and installed my Edelbrock Performer TBI intake, I custom machined my own swirl spacer, installed electric fans, hedman long tube headers (part number 69440 because no one says longtubes will fit on a 4x4) custom bent 2.25" true duals with flowmaster 40's and no cats, oh and I advanced teh cam timing 4 degrees using a cloyes roller timing set(Chevy TBI engines LOVE cam advance)

Through the stock heads, stock camshaft and stock computer this engine picked up 5 mpg on the highway and has NO problem at all burning the 265/75/16 tires through 1st, and into second with a 700R4 and 3.42 posi gears (with B&M clutches, and a B&M shift kit) and from 50km/h in 1st gear it will quite loudly bark the tires kicking into 2nd gear.

The throttle response picked up when I installed the intake and even moer when I put the spacer in and even more still when I put the electric fans on (less reciprocating mass)
The truck is super bitchin now.

On to the mufflers! I'm a huge fan of Flowmaster mufflers, however with a stock catalytic converter they're too quiet. I recommend removing the converter and installing a high flow unit (it doesn't make much if any performance difference, but the noise change is beautiful)
I've also tried dynomax bullets, as well as Hooker Aerochambers, and Cherry Bomb Turbos, and Daytona 555's
I'll rate them below for reference to anyone who wants aftermarket mufflers!

Flowmasters are my FAVORITE mufflers!! I love the sound they make at every RPM The new Super 40's are absolutely amazing sounding! 7

The Dynomax Bullets were awesome sounding,, they were the next best thing to straight pipes but they weren't stupidly loud like one would expect from a straight through muffler.

The Hookers are my second favorite mufflers, deep sounding, quiet at idle but if you lay into the pedal they scream! Expensive though

Cherry Bomb Turbo's are great sounding as well but they actually caused a loss of power,. really deep tones, awesome sound!!!

The Daytona 555's were junk. Sounded like a stock muffler!!! Don't spend the $39.95 if you want a good noise!

I like it loud, what can I say!! Thats why I'm sticking with the flowmaster 40's

If anyone is interested in hearing a few of the different mufflers I can make some sounds of them.

Just my $.02!!

Mark

Mark Mcknight 90 Chevrolet K1500 4x4, 355 Edelbrock, Isky, World Products, Harland Sharp, Eagle, JE Pistons 335rwhp @ 6200, 401ft-lbs @ 3600rpm

Axelrod
Senior Member
Posts 876
04-16-04 08:24 AM - Post#396972    

Hey Mark, thanks for chiming in on the thread. Good info.

Not surprised that your '90 TBI truck idled poorly with the Isky 270 cam but wouldn't that be the case, carb or throttle body? I would have thought that fuel delivery would actually be better at the low rpms with a TBI and electric fuel pump vs. a carb. Why'd you choose that cam?, seems like there would be a better "truck" cam choice for torque and HP at usable rpms.

On the '92, you say you picked up 5 MPG, which is great. What is your overall MPG now?

I didn't want anyone to think I'd dropped the ball on updating my project. Just taking my time and not rushing into mistakes.

I picked up a Holley TBI intake but decided not to use it. I'm going to go with the Edelbrock TBI direct OEM replacement for an cleaner overall install. Everything bolts right up, as factory. With the exception of the smaller TBI bores, which from what I understand, can be opened up to 2", it's a better choice. With the Holley intake, you have the 2" bores but have to make allowances for throttle cable, etc., as the throttle body sits about 2 inches farther forward. Mods also have to be made for brake manifold pressure fitting.

Edelbrock claims their manifold is good for 10HP at the rear wheels by itself. The game plan is to use a Holey TBI base and my flow-matched GM injector pod. I've also secured a Transgo shift kit and a Corvette servo, yet to be installed. I'm going to remove the noise reducer in the stock air cleaner or might do a Volant Torque tube instead and will then do another dyno run to verify results after manifold/TBI install.

I haven't made up my mind on further mods but am leaning strongly towards a set of L98 heads. Of course, IF, I do the heads, I probably gotta do a cam too.

On a side note, just did my first oil change and I had my engine oil analyzed by Blackstone Labs and found no bearing or ring wear evidence. Castrol Syntec is performing within limits at 5K. Had some silicon present which is no surprise given the intake manifold gasket leak. Will get that fixed soon with the intake swap.

-Axelrod
90K4x4
Member
Posts 32
04-19-04 05:38 PM - Post#396973    

The reason I picked the Isky 270 camshaft is it pulls excellent vacuum for such a healthy camshaft, and I don't really drive my trucks like trucks
As I do alot of mudding and screwin around around here with the truck, I tend to do alot of high RPM stuff (the damn Cooper STT's don't start biting into the mud till they get to about 90km/h and the last set of 265's I had on the back are laid out about 500 feet long on a local burnout road (had to show those honda's how its done!))

The camshaft is supposed to idle reasonable with a carburator, but with the TBI, and I'm not sure why but it idles like hell, really nice sound though.. Though the vacuum didn't change that much, not enough that I would have guessed a problem would have come up.

I've been told TBI's are super cranky about their Manifold Vacuum Pressure causing them to go extremely rich at idle, also making them idle very poorly, and surge. I actually have disconnected the map sensor and installed a vacuum cannister between the vacuum line and the map sensor to trick the MAP sensor into thinking that its pulling the same vacuum, it runs much better now. The cannisters can be found on 82-92 Camaro's, Cutlass' Monte Carlo's, etc.

On the 92 the mileage was right around 12 mpg, the more power it makes the better mileage I get, I'm now up to 16-17mpg assuming I keep my foot out of it enough, if I start putting the foot on the loud pedal at all it will drink a whole 120L's of gas in about a hundred km's. I've actually recorded 20mpg when I was being REALLY nice with it

I love the difference in the intake manifold when I installed the Edelbrock, not only does it look sweet (I can take pictures if anyone cares to see) it really gives the motor alot more snap, you can really feel it!! 305's generally don't lay rubber between gears no matter what shift kit you've got!!

I love the transgo shift kit, but they're a bit more involved in the install than the B&M kit and the B&M is easier to install and cheaper and gives basically the same effect. You can also just take out the springs from the accumulator and put in block offs to hold open the accumulators and you'll get a nearly the same effect as well. The corvette servo is a piece of overpriced chevy merch!!!! JET make a beauty servo that actually holds in 2nd and 4th! The vette servo only holds in 2nd!
You'll also want a good heavy duty trans cooler as the shift kit will cause the tranny to work harder to get the same tire burning shifts. I use a Mister Transmission special that cost $24.95 at the local Mister Transmission, I haven't had a problem yet! Remember 90% of all automatic transmission failures are from overheating!

My 700R4 consists of hardened planetaries, a beast sun shell, a B&M Transmission rebuild kit, a B&M 2800 Converter (my lockup is on a switch inside on the dash as well so my poor 700R4 isn't over worked on the highway or when I'm not beating the local import junk) and a street/strip B&M shift kit. I haven't even used the JET servo or even changed any governor springs and I am extremely happy with the transmission!



If you have a stock 10 bolt and a shift kit be careful of it because 10 bolts don't like tire burning WOT shifts! I found out the hard way three times now! The spiders let go and explode, Needless to say my truck is on its 3rd driveshaft, 3rd rear end, and 2nd T-case tailstock housing!

Oh yeah!! I wanted to mention DO NOT use a pete jackson, or any other gear drive on a late model motor controlled by a knock sensor! I used one on my 90 and the engine wouldn't even stay running, the computer was knocking the timing back so far because it thought it was pinging!

Chevy should have stuck TPI in all the trucks and let the crapmaro's use the TBI!!

Good Luck with your truck

Mark
Mark Mcknight 90 Chevrolet K1500 4x4, 355 Edelbrock, Isky, World Products, Harland Sharp, Eagle, JE Pistons 335rwhp @ 6200, 401ft-lbs @ 3600rpm

Axelrod
Senior Member
Posts 876
05-10-04 05:36 AM - Post#396974    

Quote:

I didn't want anyone to think I'd dropped the ball on updating my project. Just taking my time and not rushing into mistakes.

I picked up a Holley TBI intake but decided not to use it. I'm going to go with the Edelbrock TBI direct OEM replacement for an cleaner overall install. Everything bolts right up, as factory. With the exception of the smaller TBI bores, which from what I understand, can be opened up to 2", it's a better choice. With the Holley intake, you have the 2" bores but have to make allowances for throttle cable, etc., as the throttle body sits about 2 inches farther forward. Mods also have to be made for brake manifold pressure fitting.

Edelbrock claims their manifold is good for 10HP at the rear wheels by itself. The game plan is to use a Holley TBI base and my flow-matched GM injector pod.

I haven't made up my mind on further mods but am leaning strongly towards a set of L98 heads. Of course, IF, I do the heads, I probably gotta do a cam too.
-Axelrod




Latest update: I watched Ebay for awhile to see if I could pick up an Edelbrock Performer TBI. I bid on a new in-the-box one but dropped out after it got crazy. It traded for $212.50 (plus shipping) with a no name spacer included. I decided to just order one from Summit. Still have the Holley Projection (new) to sell if anyone wants it.

I got a good deal on a set of 78k cast iron L98 heads that came off a 78k mile '89 TransAm GTA. The guy I bought them from lives about 320 miles from me. To save on shipping and because I'm going to be "in the neighborhood" in June, I'll pick them up then.

I need to decide on a cam choice and whether or not I want to use headers, or put the money into porting and polishing for the L98 heads. $400 to port/polish the heads vs. $512 for Edelbrock's ceramic coated headers.

Edelbrock's TES system is only worth a claimed 10hp at the rear wheels. Porting the heads should give me at least that much extra, plus I kind of like the stock, stealthy look and the practicality of the cast iron exhaust manifolds.

Any thoughts pro or con on head work vs. headers or both would be welcome. I may have stepped this project up a bit from where I started but I'm still only looking to increase the HP/Torque in a usable truck range and to maintain or increase mileage with normal use. I'm not looking to go racing at all.

I'll keep you all posted.
90K4x4
Member
Posts 32
05-10-04 04:27 PM - Post#396975    

I've noticed chevy exhaust manifolds always blow the right hand side bullring out and they aren't designed to perform.
I replace all my chevy vehicles manifolds with hedman tubes, even cheapo headers if used with locking bolts and good gaskets they never leak for me and the power is extremely noticeable in the seat of my pants when I start mashing the go pedal! I use Hedman long tubes (PN. 69440) on all of my chevy 4x4 trucks, with custom bent pipes they are amazing pieces, I also use alstar aluminum collector gaskets with stainless hardware.
Out of curiosity why do you need ceramic headers??
I don't know much about the L98 heads but I'd say for the $400 they're gonna cost to get ported they're a worth while project!

just my $.02

Mark
Mark Mcknight 90 Chevrolet K1500 4x4, 355 Edelbrock, Isky, World Products, Harland Sharp, Eagle, JE Pistons 335rwhp @ 6200, 401ft-lbs @ 3600rpm

Axelrod
Senior Member
Posts 876
05-11-04 04:03 AM - Post#396976    

Quote:

Out of curiosity why do you need ceramic headers??
I don't know much about the L98 heads but I'd say for the $400 they're gonna cost to get ported they're a worth while project!

just my $.02

Mark




Three reasons for using ceramic, appearance, corrosion protection and last but not least, it keeps the heat in the header and out of the engine compartment along with improving scavaging. The Edelbrock shorty headers are a direct bolt up for my application and come with the Y-pipe. I've heard the Hedman long tube design is a good torque header though.

The late Chevy tuner/engine builder John Lingenfelder has said the L98 heads can really be made to flow with some porting and polishing. I've been told that the L98 heads are a cost efficient improvement over the stock swirl port heads for a TBI truck engine. Realistically, I'll be operating at low to mid-range RPMs. That's where I want the power. The engine will max out at no more than 5,000. I'll also be operating within the limitations of a tuned and "blueprinted" TBI unit. The stock L98 heads, even with the stock exhaust manifolds, would probably make me happy. The headers and porting/polishing are just icing on the cake.

The local shop I've talked to about porting says they do the intake runners about 2 inches, some bowl work and unschroud the valves. They say this provides better power and torque on an otherwise stock short block. I need to decide whether it's beneficial to pony up the bucks for both the headers and head work or just for one or the other. It always comes down to the money.
Lowtie
Member
Posts 2
05-14-04 06:34 PM - Post#396977    

Wow, nice to find some other ambitious tbi truck owners out there!! My dad and I have been working on our '90 pick-up. At 200,000 miles we decided to fix it up instead of buying a newer truck. First, we lowered it, had it painted, and had the body fixed up(roll pan, cowl hood, phantom grille, ect). It's looks nice and smooth now. Anyway, we also rebuilt an engine ourselves to put in it. We found a cheap 2-bolt 350 block out of the same vintage truck to build it up with. We bought a rebuilt kit(pistons, rings, gaskets, bearings, ect) and a new higher performance cam(218 intake and 218 exhaust @.050). For heads we bought a set of ported camel-hump(correct me if i'm wrong) "442" heads from the guy that did the block boring and hot-tanking for us. We also ordered a custom chip for it as well. Once installed with headers and duals, it ran decent, but not great. So, since then we've continued upgrading with 3.42 gears, a posi, and burning our own chips. That has made the biggest difference so far.

For christmas my dad bought me a eprom burner and we've been tweaking the tables since. Let me emphasize that in most cases that companies that burn chips are taking a guess at what the appropriate settings should be. Don't underestimate the power that can be unleased by investing a little time and money into making your own custom chips. It's really not that complicated if you do a little research. But, on the other hand, if you decide that doing so is too involved and complicated, try to find a company that will burn more that one chip for their set price. Without a proper spark and or fuel curve, power is being wasted.

Today, we bought a Holley tbi unit that we plan to put on soon. I'll post the results. I'm hoping that with the big cam and good heads to unlock a lot of high end power with the new throttle body. The next planned upgrade looks to be a tbi performer manifold. Anybody know what kind of and improvement I should see from switching manifolds? Oh, and if you were wondering about how we are using the older heads with the newer manifolds, my dad did do a little work on the center bolt holes so they'd fit.

I'm eager to see your results Axlerod, good luck!! Make sure you don't go with too big of a cam. We did, but have managed to overcome that obstacle, but have undoubtedly sacrificed some low end torque for high end hp in the process. Well, it's getting late. If any of you have any questions about the chip burning process don't be afraid to ask.

oh, and you should be able to find a good set of headers cheaper than $512!! We found a good deal on headman headers.
Southern Mudder
Member
Posts 90
05-15-04 08:43 AM - Post#396978    

My Questions for 90K4X4. What octane gas do you run since you increased the timing?

I also agree with 90K4X4 on exhuast 40 series 2 chamber flowmasters sound really good.My truck has 2 1/2 true duals, custom bent pipe, and no cats with 18inch glasspacks and 3 1/2 inch 18 inch long stainless tips so mines pretty loud.
1995 1/2 Ton 4X4 with a few goodies(more to come) The further you go, The deeper it gets

shrugger
Member
Posts 11
05-18-04 12:43 AM - Post#396979    

Ok, everyones sayin' good things about the 2030 cam
And it looks good to me
But thats not a roller cam is it?
I'm lookin to upgrade to a roller so are there any comperable to or better than the 2030
GTO_Ryan
Very Senior Member
Posts 2090
05-22-04 05:41 PM - Post#396980    

Don't forget, not all of the blocks have provisions for rollers. The only way to find out is to open it up and take a look.
'69 Pontiac GTO 400ci V8 '92 Chevy Blazer '99 Chevy Silverado 5.3L We need an air strike!

Elly
Member
Posts 43
05-24-04 09:14 AM - Post#396981    

Im sure I already know the answer but will these mods work for all SBC?
If you can't be good, Be good at it!

90K4x4
Member
Posts 32
05-24-04 01:31 PM - Post#396982    

I run 87 Octane fuel and a bottle of Octane Booster (I get the stuff for $2 a bottle so its cheaper than spending $15 mroe to fill the tank) Unless its hot out in which case I use Sunoco 94 fuel and octane booster..
It doesn't normally ping unless I'm climbing a really steep hill with my car trailer on or just running the ever loving [naughty word removed and users mouth washed out with soap] out of it

Mark Mcknight 90 Chevrolet K1500 4x4, 355 Edelbrock, Isky, World Products, Harland Sharp, Eagle, JE Pistons 335rwhp @ 6200, 401ft-lbs @ 3600rpm

90K4x4
Member
Posts 32
05-24-04 01:36 PM - Post#396983    

Quote:

Ok, everyones sayin' good things about the 2030 cam
And it looks good to me
But thats not a roller cam is it?
I'm lookin to upgrade to a roller so are there any comperable to or better than the 2030




Why do you need a roller cam unless you're pulling lots of RPM? Sure they make more power but they're also more costly.. And if you're going to upgrade your cam especially to roller, you'll hafta do your heads too because your cam won't match your cheapo stock 193 heads.
Just my $.02

Mark
Mark Mcknight 90 Chevrolet K1500 4x4, 355 Edelbrock, Isky, World Products, Harland Sharp, Eagle, JE Pistons 335rwhp @ 6200, 401ft-lbs @ 3600rpm

shrugger
Member
Posts 11
05-24-04 07:39 PM - Post#396984    

Now that I've got it apart I do have a roller ready block
As for the 193's that I pulled off, they'll make great cores(or boat anchors)
for the L98's I plan on puttin back on.
I might go with vortec's if I can figure out the EGR pluming for 'em

I'm just tryin to wheeze as much power as I can from this motor
Impalaman1966
Senior Member
Posts 6228
05-25-04 04:04 PM - Post#396985    

car craft, and chevy high performance magazines are both doing buildups on 93 chevy pickups. they are dyno testing everything, so you'll get real numbers. get the june and july issues if you can.

InfernoSRT8
Senior Member
Posts 863
06-05-04 04:53 PM - Post#396986    

Roller is a reasonable easy upgrade( in some cases, I will get to that) and has its benefits. Roller cams in 87 up motors wasn't for power, it was for reliability and fuel economy. The less frictional losses you have the better, as far as not matching the heads, no performance cam, roller or not matches the 193 boat anchors, however the only needs if you have roller provison is:
camshaft
lifters
thrust plate
distributor gear
spider
lifter reatainers and pushrods
timing chain and gears

Most of that stuff is replaced on a rebuild anyways and everything except the timing chain and lifters( some guys will use used, maybe if they are really low mile and clean, true they have no real break in but its still a used piece) can be sourced from any old 87 up Caprice or Camaro 305 in your local Pick a Part yard.

However as mentioned many of these 87 up TBI truck engines are not roller ready, like my 92, there were no bosses in the lifter valley. So if it has bosses you can do the cheap stock GM way, otherwise it is the more expensive aftermarket link bar lifters. Flat tappet works fine as well and there is nothing wrong with them, but if you have the option roller is the better way to run, its gains are real world. Plus with a roller more duration and lift are acceptable because of the low friction environment allowing them to idle better than an equalivalent flat tappet cam, something to consider.
2006 Dodge Charger SRT8
1994 Chev reg cab s/b 2wd
1986 GMC 1/2 ton 4X4 6.2 Diesel

shrugger
Member
Posts 11
06-05-04 08:35 PM - Post#396987    

I guess I got lucky, my motors from a 90 Suburban
so far I've found nearly everything for amazing prices
off of ebay or reasonable prices from Jegs.
L98's,roller lifters,throttle body etc.
I pretty much just need to choose the right cam and I'm ready to roll. Pardon the pun
dthill
Member
Posts 15
07-28-04 08:36 AM - Post#396988    

Quote:

This is what I was thinking: I'd like to get an improvement in Torque/HP of maybe 10-20%, without a give up in mileage or drivability. Would a mild cam swap, K&N filter system or the equivalent, and a efficient, manifold back, exhaust system get me there?




My question is: how will all this affect longevity of the truck? It *seems* like it would shorten the lifespan.......
Need a clue here,.........
loudpedal
Super Senior Member
Posts 5010
07-28-04 10:43 AM - Post#396989    

Need a clue here,.........

if you keep everything to a mild roar....keep the c/r to about 9.5:1 or lower.....as well as the valve lift, the drivability nor the longevity of the motor will not be affected....the key is to do moduifications that you do not need to use premium fuel , and not to make increases /add ons that will necessitate rechipping...as that can be problematic as pointed out above...UNLESS you willing to spend a lot of time on a learning curve or farm the chip work out. Towing or hauling big loads of course puts higher loads on everything.....as well as heavy foot driving. Drive normally and have a happy drivetrain.
loudpedal
Super Senior Member
Posts 5010
07-28-04 10:45 AM - Post#396990    

C-man........

"Roller is a reasonable easy upgrade( in some cases, I will get to that) and has its benefits. Roller cams in 87 up motors wasn't for power, it was for reliability and fuel economy"

It wasa for power also.......a lot more under the curve on a stock roller profile vs a stock flat tappet design. I'll bet 10 to 15 hp from a stock flat lifter to a stock factory roller.
InfernoSRT8
Senior Member
Posts 863
07-28-04 03:20 PM - Post#396991    

Well it is very true that roller is a power gaining way to go that is not the reason GM officially did it. The easiest way to look at it that way is whether a TBI 350 or 305 for that matter was in a truck or a car, same or very similar power rating. Now it was done that way even though, all car motors are roller and the truck ones are flat tappet. However I don't disagree at all, but GM thought it made no difference, and with the puny stock cams, it doesn't, not really anything thats measureable anyways. You may get slightly better throttle response with the roller TBI's but for all out power, I drove both and stock for stock their is no difference. Its when you add aftermraket cams into the mix, or larger at least, where you realize the benefits of roller over flat tappet.
2006 Dodge Charger SRT8
1994 Chev reg cab s/b 2wd
1986 GMC 1/2 ton 4X4 6.2 Diesel

John k
Member
Posts 11
08-05-04 08:34 PM - Post#396992    

Great thread. A couple of things that I have found out. One company that specializes in tbi www.cfm-tech.com told me that the vortec heads are really tough to get a chip programed for. They said that they have too much vacume, which causes major chip programing problems. I have a 1990 Blazer with a 350 and man trans. I bought the truck from a person who stated it has a 330 hp motor in it. The motor is not a chevy crate motor, and as such does not have vortec heads. I have no idea what the cam specs are, but it does have a lopey idle. I installed the spacer that raises the injectors 1/4" and a 1" tbi spacer. I did feel a little more power after installing these two items. cfm tech offers a 1" spacer that has a cut between the two bores. It is cut about half depth and then a 45 degree angle is milled for smooth flow. I milled my spacer the same way the cfm tec spacer was shown in the picture. It feels stronger, especially at top end. Go to their web site for the explanation. The Blazer also has a H.P. Chip, but I don't know much about it. It now has headman headers and a duel 2.5" system, no cats. The problem with the Headman headers is that the collectors point downward. To get the pipes over the crossmember, it required a very sharp bend in the pipes. I just bought a new set of Hooker headers. The collectors on these point slightly up. They have a longer 2.5" collector vs. the short 3" collectors on the Headman. The 2.5" collectors should help low end torque. I got the Headman 2.5" "s" pipe that attaches to the collector. They allow a smooth transition up over the crossmember. The Headman "S" pipe have the end set up for a 3" collector, so I had to cut off the end and will attach them to a 2.5" reducer. The Hooker headers are really good looking and fit well. I also installed the soup bowl looking adapter that goes between the top of the tbi and the bottom of the air cleaner. It costs $43.95. A dyno test done by Car Craft showed 10 HP and 10 Ft Lb of torque at the rear wheels with the soup bowl added. It replaces the adapter between the tbi and air cleaner. It allows air to flow into the tbi at a much better angle. The test was done on a stock 350 with the stock air cleaner. Pretty cheap horse power. The Blazer runs darn strong. I will be adding the larger tbi unit, Holly manifold, fuel pressure regulator and higher pressure fuel pump at a later time. I have a Vortec short block in the garage with only 6K miles on it. As soon as my 350 gets tired, I'll build it with a roller cam. A MSD 6a, and K&N air filter in the stock air cleaner with the cold air pipe are the other mods. Be sure to change the fuel filter often. They seem to plug up quickly and will burn out the fuel pump in short order if plugged. I get 17 MPG. Not bad considering that I live at 6500 feet and run over a mountain pass to go to work every day with 10% grades that goes to 8500 feet. Keep the ideas coming.
John K
www.savagegunsmithing.com Earth First!!! We'll 4 wheel and hunt the other planets later!

John k
Member
Posts 11
08-06-04 07:34 AM - Post#396993    

I drove the Blazer again today after making the cut in the 1" spacer. It feels quite a bit stronger. It's a good mod. The spacer that is already cut sells for $90.00. If you have access to a mill, you can get a spacer on e bay for far less money and mill it yourself. Next to the "soup bowl, it has given me the most HP for the least amount of money. It allows the manifold to pull from both barrels of the TB. With the small amount of airflow that goes thru the TB, any increase really helps. Especially on a modified engine.
John K
www.savagegunsmithing.com Earth First!!! We'll 4 wheel and hunt the other planets later!

trux0rz
Member
Posts 66
trux0rz
08-10-04 09:05 PM - Post#396994    

Ok guys, tell me what you think. Im currently starting the buildup of a 350 for the truck. So far ive ordered the edelbrock performer manifold for vortec heads and a tbi adapter plate. The heads on ebay im looking at are the L31 cast iron vortecs. They are fully refurbished with stainless valves, hardened seats, valve locks and retainers. They also have a 5 angle valve job. The block will be bored 030 over, and ill stay with the stock rods, unless any damage has been done to them. The crankshaft will be resurfaced and balanced. My main question is what pistons to run. Nothing too fancy, but maybe some lighter ones? Ill be running some summit truck headers with a y-pipe and single exhaust with some kind of muffler(any recommendations?) Also will a stock 454 tbi cut it? Any other tips? Cam recommendations? Thanks in advance, Bobby.
92 std cab long box 4wd 00 ext cab long box 2wd

shrugger
Member
Posts 11
08-11-04 12:13 AM - Post#396995    

I just went with TRW cast pistons .030
They were only $13 each. Since I dont expect I'll exceed 300hp They should be just fine.
I dont know what my c/r will be since the deck needed milled
and the L98 heads I'm using needed a little smoothing


John k
Member
Posts 11
08-11-04 07:19 PM - Post#396996    

I would go with the Hypereutectic pistons. They are stronger than cast pistons, and are fitted tightly to the bore. They will last longer in a street engine, use less oil and not wear out the block as fast. Forged pistons are fine if you are using nitrous or a blower, but for a normally asperated engine they are not needed. Try to keep the compression ratio about 9 to 1 if you want to run regular fuel.
John K
www.savagegunsmithing.com Earth First!!! We'll 4 wheel and hunt the other planets later!

1993GMCPU
Senior Member
Posts 189
08-16-04 04:28 PM - Post#396997    

Summit had: STL-H345NP30
$12.88
Should Ship By: Tomorrow
Dominating the horsepower-per-dollar race.
Chevrolet: 350, .030 in. oversize, 4.030 in. bore, 3.48 in. stroke, 5.7 in. rod length, flattop, hypereutectic piston
If youíre looking for pistons with an unbeatable combination of performance and value, these hypereutectic pistons are for you. Manufactured from FM244 aluminum alloy that contains 16 percent silicone for greater strength and wear resistance, these pistons are molded in the latest permanent mold technology to ensure the precise fit and tight bore clearances todayís top engine builders demand. Theyíre ideal for use in high performance street, bracket racing, and oval track and will work perfectly with normal ring end gaps.
Vendor Speed Pro
Product Line Speed-Pro Hypereutectic Pistons
Material Hypereutectic
Finish Machined

Matt
Moderator
Posts 7709
Matt
08-17-04 07:19 AM - Post#396998    


For those who want to upgrade your truck's intake system for a better breathing engine - do what I did because I did notice a difference after doing those mods several years ago. They are still working like new - no signs of wear and tear at all.

1) get the JEG's Ram Air air tunnel. this replaces the factory restrictive air tunnel from the inner fender to the air intake housing. Only available from JEG's. Click here for the link

2) Get a K&N filter, the simple replacement one. Click here for the link

3) Get the Hypertech PowerCharger. click here for the link

viola! a inexpensive and functional intake system - and the elements are not exposed to heat/mud/water like a FIPK would be with the open filter.

all of the above links were from JEG's. Only the air tunnel come from them, but the filter and power charger, u can get them elsewhere if u find them cheaper.

tomato
Member
Posts 20
08-21-04 08:26 AM - Post#396999    

Anybody just flip the top of the stock airfilter box over and screw it back down? I don't know if it helps horse power but it sure makes a neat sound.
Dana
Member
Posts 11
08-22-04 01:16 PM - Post#397000    

Quote:

I drove the Blazer again today after making the cut in the 1" spacer. It feels quite a bit stronger. It's a good mod. The spacer that is already cut sells for $90.00. If you have access to a mill, you can get a spacer on e bay for far less money and mill it yourself. Next to the "soup bowl, it has given me the most HP for the least amount of money. It allows the manifold to pull from both barrels of the TB. With the small amount of airflow that goes thru the TB, any increase really helps. Especially on a modified engine.
John K




I've recently done the exact same thing with my Suburban w/350 motor. Bought a $26 1" thick aluminum TBI spacer on eBay, and machined it like the CFM-Tech one. Works fantastic. I also added the Injector Pod spacer $12 on eBay which makes for a wider cone pattern for the injectors. I modified a utility lamp reflector (the kind that clamps onto things) I bought for $8 at Home Depot, and cut with snips. To this aluminum "salad bowl" I added some rubber edging for reinforcement along the cut edge. This piece now performs the same job as the $45 Hypertech power charger, although it is somewhat more delicate. I cut the stock aircleaner hole to work with the power charger. I also added a second cold air intake on the drivers side using 3" aluminum dryer hose and making flanges to go through the air cleaner and a 3" hole behind the headlights. I removed the stock fuel pressure regulator and made it adjustable. I am now running it at 14psi, vs the 12 psi it was from the factory. All these mods have made a substantial difference in the performance of the truck. It accelerates much stronger above 1/2 throttle, has a higher top speed, and overall driveability is improved. Throttle response is much better. I think gas milage should be improved but I haven't noticed, since I am having so much fun driving it now my right foot has been quite busy.
Thanks, Dana ~~~~~~~~~~~~~~~~~~ '91 Suburban 2x4

trux0rz
Member
Posts 66
trux0rz
08-22-04 01:18 PM - Post#397001    

Im still puting together some info on my engine. The block is a 90 2 bolt. Ive heard somewhere Milodon makes 4 bolt main caps if you have the block machined for it. It retains the factory 2 bolts, but then has 2 extra splayed bolts. Im guessing the motor will put out somewhere around 280-300 horses. Does anyone think I'll need a 4-bolt? Im putin on vortec heads and an edelbrock performer w/ a tbi adapter. Thanks in advance.
92 std cab long box 4wd 00 ext cab long box 2wd

trux0rz
Member
Posts 66
trux0rz
10-01-04 05:26 AM - Post#397002    

The motor is done!! Went with KB hypereutectic pistons, and a cam the builder had layin around from a vette, not sure what the specs are, but he said its basically the strongest cam to run w/ a tbi system. Im goin with an adjustable fuel pressure regulator, stock 350 injectors and bump it up to around 15 psi? Not too sure yet. Edelbrock perormer manifold. Most likely flowtech afterburners(if i win on ebay) and 3" single exhaust. cant wait to get it in, just gotta find the oil filter adapter relocator thingy.
-bobby
92 std cab long box 4wd 00 ext cab long box 2wd

dustinova
Senior Member
Posts 143
dustinova
10-01-04 07:33 PM - Post#397003    

Awesome!!! Let us know how it turns out.
Dustin - '90 C1500 V6, 700R4, Reg Cab, Short Box

curlymd
Member
Posts 24
10-20-04 06:46 PM - Post#397004    

hey, i'm looking through that website, http://www.tbichips.com, and i still can't find that chip u recomend for only $39, do they just not sell it anymore or am i that blind?
dustinova
Senior Member
Posts 143
dustinova
10-20-04 07:36 PM - Post#397005    

I could never find it either. They must have either discontinued it, or raised the price a bunch.
Dustin - '90 C1500 V6, 700R4, Reg Cab, Short Box

someotherguy
Moderator
Posts 25471
someotherguy
10-21-04 08:23 AM - Post#397006    

He had a notice on there about having to raise the price due to this or that; look at it this way: his product has consistently gotten good reviews on here, it's still far cheaper than any of the alternatives I've seen from other companies. So I'd say it's still worth it, if you're in the market for a chip.

Richard
94 C2500LD / 94 C1500 / 06 300C SRT8
Check out my truck shop projects

curlymd
Member
Posts 24
10-21-04 04:19 PM - Post#397007    

oh yeah, i agree, it's still a really good price for a performance chip. but i used the price as a way to find the chip that he used which i couldn't find, but since it has gone up now i know which one to get
curlymd
Member
Posts 24
10-21-04 04:51 PM - Post#397008    

just out of curiousity, do you know how much power increase a stage 1 chip from that site give?
curlymd
Member
Posts 24
10-24-04 03:27 PM - Post#397009    

hey, for all the people who put the stage 1 chip in their truck from that tbchips, did ya'll run it with the stock cam?
someotherguy
Moderator
Posts 25471
someotherguy
10-24-04 03:28 PM - Post#397010    

I haven't bought any of his chips.. I'm still running the stock stuff. My engine mod plans don't involve using the ECM.

Richard
94 C2500LD / 94 C1500 / 06 300C SRT8
Check out my truck shop projects

stahlecker
Senior Member
Posts 137
10-25-04 12:19 PM - Post#397011    

I have one and am running it with a stock cam. I am not shure of the exact power increase but it is definatly noticable. There is more power there.
1991 K-1500 Silverado Reg Cab Longbox 350 Auto

curlymd
Member
Posts 24
10-25-04 01:13 PM - Post#397012    

i e-mailed him and he said for my truck ('92 5.7L) he said it would add bout 20 hp. and he said the it would be find with the stock cam in another e-mail, i guess he just suggest another cam with the chip would make an even better improvement which any cam mod would be true
curlymd
Member
Posts 24
10-25-04 01:41 PM - Post#397013    

also, can u tell where the power increase is? like in low-end or mid-range?
stahlecker
Senior Member
Posts 137
10-25-04 04:13 PM - Post#397014    

Midrange really shines. But I can tell there is more all the way through the powerband.
1991 K-1500 Silverado Reg Cab Longbox 350 Auto

curlymd
Member
Posts 24
10-25-04 04:15 PM - Post#397015    

sweet cuz my midrange is where i'm sufferein, my truck was definitly built to just toe
matthewwest
Member
Posts 89
matthewwest
11-02-04 05:52 AM - Post#397016    

I e mailed tbichips and he recomended this cam for my truck. He said the chip would work with a stock engine, which I have now, or that cam and Performer intake, which I plan on using later.
88 Chevy K1500 5.7L Poweraid throttle body spacer, K&N cold air intake. Summit cam, Stage1 chip, Performer intake

Trickybone
Member
Posts 9
11-05-04 01:38 PM - Post#397017    

Okay, I have several questions on somewhat different lines so please bear with me. This is an awesome thread, & I can only assume that others would eventually ask the same questions:

1. Did anyone using Vortec heads change the valve springs when they changed the cam? I've heard the stock Vortec springs are weak and have a hard time handling a stronger cam. I'm running Vortec heads with the Compucam 2030 (206/214).

2. What brand Fuel Pressure Regulator are you guys running? Would you recommend it to others?

3. Those running Hedman long tube headers-- any problems routing the collectors above the crossmember? How about leaks, any problems keeping them sealed up? What type of gasket at the head to you use/recommend?

4. Anyone have more information on the mercruiser 350 TBI w/ 2" bores? Same connectors (aka is it a direct replacement for stock 350TBI if intake is bored)?

Thanks in advance to all the replies. This is a great forum!

My Truck:
88 GMC 4x4 K1500 Stepside
5.7L 350ci w/ Vortec heads, GMPP TBI intake
Crane CompuCam 2030
90K4x4
Member
Posts 32
11-13-04 05:59 AM - Post#397018    

Hey,

I hear the vortec has excellent factory springs?? I don't personally use them, but your cam won't hurt the factory springs in a TBI head even so I can't see you having any trouble with a vortec headed engine
JET performance makes an adjustable fuel pressure regulator, which is the one I'm running now, it works good but a pain in the A$$ to adjust..
I run the hedman longtube headers (PN 69440) and I have absolutely no problems at all, aside from having to remove the bracket for the power steering pump that bolts to the first manifold stud on the drivers side, I use copper gaskets in the collectors and MR. Gasket graphite gaskets in the headers but they still manage to blow out every 20,000 kms or so, its all part of having 5 1/6 flange headers.. I'd like to try the percys dead soft aluminum gaskets, probably will next time, I'll keep you posted.. If you're interested in seeing how my exhaust is laid out let me know and I'll shoot you some pictures!
Good Luck!

Mark
Chargerguy521@hotmail.com
Mark Mcknight 90 Chevrolet K1500 4x4, 355 Edelbrock, Isky, World Products, Harland Sharp, Eagle, JE Pistons 335rwhp @ 6200, 401ft-lbs @ 3600rpm

matthewwest
Member
Posts 89
matthewwest
11-24-04 10:53 AM - Post#397019    

So let me get this straight. L98 iron heads will bolt right up to a 1988 5.7 350? And the intake will match up to them? Should I have any machineing done first? Same question for LT1 heads.
88 Chevy K1500 5.7L Poweraid throttle body spacer, K&N cold air intake. Summit cam, Stage1 chip, Performer intake

racincade
Senior Member
Posts 791
racincade
11-25-04 09:41 AM - Post#397020    

Yes the L98's will bolt right up, those are your best bet for not having any troubles, The vortechs will give you more troubles wich will bring more headaches. The STOCK TBI can keep up with those great flowing heads. Or you can ditch the TBI and go with a carb.
2003 3/4 ton HD ext cab 6.0
2004 YFZ 450 - FAST-


smokey212
Member
Posts 5
12-27-04 07:28 PM - Post#397021    

I've got hooker long tube headers on my 96 z71 and when we ran the pipes we had to take off the skid plate for the transfer case. Then we had to guestimate on the bend for the pipes. Eventually we got it to fit by snaking it around the crossmember so we wouldn't have to weld two pieces together. As far as leakes the first two sets of exhaust manifold gaskets were that felpro's, clay or whatever that stuff is. Then I switched to a copper gasket and never had another problem in 30+ thousand. The collectors I used that soft aluminum stuff for a while, and they kept breaking. Then I just put it back together with no gasket at all and put those 1/2 thick support things around each side of the flange and bolted it tight. It hasn't leaked since, and I go to some pretty rough places.
smokey212
Member
Posts 5
12-27-04 07:31 PM - Post#397022    

One question. Does anyone know where to get those wires you splice into your rear oxygen sensor to get the service engine light to go off?
racincade
Senior Member
Posts 791
racincade
12-30-04 07:03 AM - Post#397023    

Whered you got those headers at?
2003 3/4 ton HD ext cab 6.0
2004 YFZ 450 - FAST-


MikeJ
Moderator
Posts 4173
MikeJ
01-03-05 06:49 AM - Post#397024    

I"ve got a set of copper gaskets waiting for install on the wifey's 92 headers. Did you do anything special when you installed them?
Mike


Farmer Mike
Member
Posts 25
03-11-05 08:36 AM - Post#397025    

What happened to this awesome thread? Why did everybody quit posting? Well, I've read this over and over and got some great ideas. I just got an Edelbrock 3704, fresh 083 TPI heads and I'll be picking up a Crane Powermax 2030 cam. My truck is an 87 V10 with a fresh GM crate 350. It presently has a chip from Tbichips, Holley 502-6, and highflow cat with 3" single exhaust. I'll post my results after I get everything installed. I found a link to some fantastic TBI info!! The third generation Camaro board is doing crazy stuff with TBI motors (especially 305s). Check them out...

http://www.thirdgen.org/

How about some more feedback on everybody's mods????
dustinova
Senior Member
Posts 143
dustinova
03-11-05 11:45 AM - Post#397026    

What crate 350 did you use? Is it the generic goodwrench 350, or is it the vehicle specific 350 replacement motor?
Dustin - '90 C1500 V6, 700R4, Reg Cab, Short Box

Farmer Mike
Member
Posts 25
03-11-05 03:31 PM - Post#397027    

I bought a 350 TBI P/N 12568758 from a local Chevy dealer. If you're interested in getting a crate engine, call around to all GM dealerships in your area. You wouldn't believe the differences in price between one dealership and another.

I just finished replacing the diff covers to figure out my gear ratio. Holy crap! It's got 3.73 gears! It's such a dog at higher RPM that I thought I had 3.08 or higher gears. I'm really hoping the heads, cam, and intake will make a big difference. The next step will be to figure out how to hook everything up to do some data-logging. I'm not really excited about burning my own chips but I'd like to get a fairly customized chip made. More to follow...
GMCTECH
Member
Posts 10
03-26-05 01:44 AM - Post#397028    

It did kinda fizzle a bit, I was wondering if anyone else has had the awesome results from the jetchips stage 2 that I have. 1.2 to 1.5 MPG increase and I think the advertised 15 to 20% HP increase is really understated
Farmer Mike
Member
Posts 25
04-19-05 08:42 AM - Post#397029    

I finally have all my new parts installed (L98 heads, Crane 2030 cam, and Edelbrock 3704 intake) and have put 50 miles on it after break-in. I'm happy it's all back together but I'm not too happy with the results. The new cam is making the truck run way too rich and it feels a lot more sluggish than before (with timing set to 8 degrees BTDC).

I know the ECM really needs to have a new chip burned so I'll get started with some datalogging and learn how to burn my own chips. In the mean time, it's going to run like a real pig.

Some of the lessons learned would be to NEVER install a harmonic balancer without the harmonic balancer tool (almost totally mangled the threads inside the front of the crank), take off the pan before taking off the timing chain cover (pan gasket is one piece and you'll never get the gasket to fit without taking the pan off), and always know when the motor is at #1TDC or #6TDC (I totally hosed the initial valve adjustment).

Does anyone have any wisdom they'd like to share to help me tune this thing up?

Thanks!

Mike

87 V10 4X4: 350 GM crate engine with Holley 502-6 TBI, TPI heads, Crane 2030 cam, Edelbrock 3704 intake, tbichips.com chip ,3" exhaust with Hiflow Cat.
F.I. 57 Belair
Member
Posts 11
04-24-05 03:50 AM - Post#397030    

Farmer Mike, I have followed your posts on upgrading your 87. I have installed a rebuilt short block in my 87 R20 with Vortec Heads, Comp cams 12-249-4 cam, Holley TBI Afterburner headers GMPP tbi Vortec Intake.I had problems with getting it to run because of the increased vacumm from the Vortec Heads. I contacted Brian at TBI Chips and had him burn me a custom chip. My truck now runs much better. My next move is to send him a WINALDL scan so he can fine tune my chip. I would recommend you get in touch with him as he is very knowledgeable at tuning this type of setup. By the way I highly recommend the Afterburner Headers. They fit better than any I have ever installed in the past. Only had some minor tube dinging for easier bolt access. I had no problems installing Dual Exhaust, no leaks, good spark plug accessibility. I also installed a heated O2 sensor in the collector. I think with further tuning it will be capable of 300 + HP. It seems very responsive. Has great bottom end throttle response Great passing gear, Will run the speedometer around to zero with no problem. It runs very well for a 3/4 ton 4WD. Anyone else out there with a similar set up? If so lets hear from you. This has been a yery imformative thread. Lets keep it going.
F.I. 57 Belair
Member
Posts 11
04-24-05 04:16 AM - Post#397031    

Farmer Mike, I have followed your posts on upgrading your 87. I have installed a rebuilt short block in my 87 R20 with Vortec Heads, Comp cams 12-249-4 cam, Holley TBI Afterburner headers GMPP tbi Vortec Intake.I had problems with getting it to run because of the increased vacumm from the Vortec Heads. I contacted Brian at TBI Chips and had him burn me a custom chip. My truck now runs much better. My next move is to send him a WINALDL scan so he can fine tune my chip. I would recommend you get in touch with him as he is very knowledgeable at tuning this type of setup. By the way I highly recommend the Afterburner Headers. They fit better than any I have ever installed in the past. Only had some minor tube dinging for easier bolt access. I had no problems installing Dual Exhaust, no leaks, good spark plug accessibility. I also installed a heated O2 sensor in the collector.
1983G20Van
Super Senior Member
Posts 3223
04-25-05 02:02 PM - Post#397032    

TBI 350 modifications of mine clipped from thirdgen.org. Beware it is long and probably boring.

I recently ported a pair of TBI 350 193 swirl ports as an experiment. I went into it knowing that they are swirl ports and can only have so much potential. Thing is when I got done and had a buddy flow bench them, the flow #s suprised me. Not bad for 8 hrs with a air grinder.

Valve Lift------Intake Flow---------Exhaust Flow
.050--------------35.6----------------------31.0
.100--------------72.4----------------------60.5
.150-------------105.8---------------------87.3
.200-------------133.4--------------------124.2
.250-------------154.1--------------------147.3
.300-------------180.6--------------------171.5
.350-------------195.5--------------------184.7
.400-------------209.3--------------------196.3
.450-------------217.4--------------------203.7
.500-------------224.3--------------------215.6

All I did was knock the casting flash off the intake, reworked the intake bowl area and swirl ramp (swirl ram is still in place), then reworked the exhaust like you would any small block head. I also unshrouded and opened up the chambers slightly around the intake and exhaust valves. The heads still exhibit very strong swirl. While cleaning them I sprayed water into the intake port and recieved an unexpected shower. The swirl port literally threw water out in about a 6' diameter area. The heads were flow benched at 28 in/h20 just like any other head.

Notice how much better the exhaust flow is than the intake considering the intake is through a 1.94" valve and the exhaust a 1.5"

These heads are going onto a 350 TBI with either a vortec cam or LT1 cam. Probably the vortec since it only has a mild performance spring and considering that over camming won't help performance much.

I wish that someone knew what these things flowed stock??? Should have thought to check one before I reworked it.

I know the final say will be the chassis dyno and track.

The air velocity around the outer edge of the swirl ramp and bowl is very high. Used a hair dryer set on low to blow into the port and a mist of water to see what kind of velocity and swirl the port made.

I used stock sized valves from Precision engine parts their pro series. They were cheap when I bought them a year ago, are under cut, swirl polished, stainless and of a very high quality. I got them from a local engine builder. When I was learning how to port (had an expert friend help me through the first set (my 601 305 heads) the precision engine parts valves in those heads were worth almost 15 cfm on the intake and 8 cfm on the exhaust with no changes other than changing the valve.

The valves were done with a 5 angle valve job. (Buddy had the tools so all it took was a little extra time)

I also spoke with three professional porters and they told me that the swirl ports are GMs sleeper heads. One told me that he is consistently able to make them perform up to vortec horsepower levels on an engine dyno. He also commented that the low to mid range torque was much greater on the TBI heads. When you get to thinking about it if it cost $400-600$ to get a set of TBI heads rebuilt and ported to vortec levels it would be very worthwhile. All you have to do is increase the velocity and open up the port slightly below and around the swirl ramp. I also ground the swirl ramp into a U shap to help it flow better. You want to keep the swirl ramp because it greatly adds to the flow through the valve at low lifts by litterally spiraling it out in 360* around the vavle.

I wouldn't really call myself an experienced porter although I have ported about 5 sets of heads and have about 200 hours on my air grinder. Total time for these heads including research and valve job cam to just under 20 hours. I only spent about 8 hours with the air grinder in my hand.

My first set of 305 HO heads flow about 15 cfm more on the intake and 20 cfm less on the exhaust.

All of the ports flowed within a few CFM of each other so I must have done something right.

I am glad that in my moment of indecisiveness last night I stuck the 1993 F-Body LT1 cam I have laying around my garage into the engine. I believe that that cam is a single pattern. The heads are on the shortblock, the cam is in it, all the lifters are in, pushrods set, valve covers are on and finally the edelbrock performer manifold is back on. The engine is back in, all the accessories are installed and the engine was test run for 15 minutes.

I am topping this engine with a TBI w/ ultimate tbi mods, 65 lb/hr injectors, and 15.5 psi fuel pressure. I know I am going to have to do some chip work but that isn't a problem. I have played with burning chips and have had a 454 TBI sytem running on a 307 olds with good results.

I helped a friend do the ultimate TBI mods, put headers, edelbrock TBI intake and a melling MTC1 cam into a 1994 chevy truck with a 350 (don't like the edelbrock TBI cam as it isn't much hotter than stock). The mellings cam ran good with the factory TBI injection and about 15 psi fuel pressure and 4* advanced. The thing pulled great from about 1,200 to the 4,500 rpm shift poit. Those 3 mods really woke the 350 TBI engine up. Truck dyno'd 230 rwhp an 290 ft/lbs at the rear wheels through a 4L60E. Probalby would have run better with a better tune.

The Mellings cam specs out at 204* intake and 214* exhaust at .050", .422" Intake lift and .444" exhaust lift and 114 lobe center.

Idle was a little different from stock but still made 20 in/hg of vacuum and had great throttle response. Not to mention the mods were made when the timing chain needed to be changed and only cost about $500 total.

Worked on it some more this evening and have a funny story.

Actually datalogged and used a wide band on the engine today. It doesn't even need much if any more tuning after the first two chips. All I did was adjust the injector constant, change the PE and open loop air fuel mixtures, and eliminated the PE timing and added what was needed to the main fuel table. Wide band says that I am at 12.7: 1 all the way across the board while in PE. I can live with that. VE tables seem pretty close because I am sitting at 124-127 BLM across the whole table.

The engine runs like a rapped ape even pulling all that weight and those gears. Had a friend with me when I was datalogging. He was running the laptop and the wideband while I was driving. A civic with a wing and fart can pulled up next to me at a light. Keep in mind that I am datalogging and using moderate acceleration out of lights, up this hill that is about 1 1/2 miles long. On top of the hill is a flat, straight section of road that is divided by a concrete dividing wall for several miles. Nothing out past this light as it is between two cities. Figured it would be a good place to populate the 80-100 KPA sections while under moderate loads and at speed as the limit is 70 on this particular road. Start off from the light at about 1/3 throttle partially due to the fact it is a new engine, and I wanted to check AE. Only problem is the tires screech a little due to the instant torque rise and the fact that I am sitting on a hill. Also my 40s are kicking out their mean growl. Civic kid thinks that it means I am trying to race him, so he nails the pedal. Well once I get traction I hit it to 2/3 throttle, transmission shifts into 2nd @ about 2,800, goes through 2nd, shifts 2-3 at 2,800. It then goes into OD at about 75 and the converter locks up. All this time I hear this little engine screaming beside me. All I do is keep it about 2/3 of the way down and I started leaving him like he was sitting still (his engine screaming, mine just loafing along at Part Throttle, in OD up this hill).

My laptop recorded 108 mph on the dataloging while in OD at 1/2 throttle with 3.08 gears in closed loop with STOICH set at 15.4:1!. Talk about some mid-range torque.

Didn't actually think that I had it much over 85 (needle was pegged but you don't pay much attention to it at that speed) but apparently the VSS and WinALDL think that I did.

Basically I beat a civic in a 5,300 lbs brick, with a 355 TBI, 3.08 gears, at part throttle, while driving up a large hill.

The thing runs awesome and is still getting 17-19 mpg on the highway on my 40 mile commute. I took it to the 1/8 this last weekend and ran a 10.32 @ 70 with a 2.55s 60", which isn't bad considering it is a two barrel 350 pulling a 5,000 lbs brick with 3.08 gears and an automatic. I left the line at idle and let the transmission shift 1-2 automatically at 5,000 rpm and trapped the 1/8 at about 3,800 rpm in 2nd. Even with 255/70/r15s and a posi, traction is still an issue. I am also very gear challenged. I have not dynoed mine yet as I am still dialing everything in. By my 1/8 mile run I would say that I am atleast making decent HP and TQ.

NorcalZ71- In an above post I mentioned the specs of a friends 94 350 TBI truck that I helped modify. The cam was a basic, cheap RV cam that ended up with good results even on the stock tune. All that was done is advance the timing some and add fuel pressure. Car Craft got like 185 RWHP out of a bolt-on 350 TBI truck engine without going into it. On the otherhand this truck was 234 RWHP and 295 ft/lbs to be exact. Very little was done to this truck, RV cam, raised fuel pressure, headers, ultimate TBI mods, open element, and an Edelbrock intake (might as well since it is off for the cam swap). The truck runs great despite the mods and the factory ECM tuning, in fact he gained about 1-2 m.p.g. over stock.
The mellings MTC-1 cam that is in that truck is almost the same if not the same as the crane 2030 cam. I ran it in my 305 headed 350 before switching to the LT1 cam. It made nearly identical numbers to my friends truck on the stock 1992 van prom and tbi setup.

What gear was the torque dynoed in 2nd? 348 ft/lbs is roughly 425 ft/lbs at the crank!!!! I thought the 295 (360 flywheel tq) out of my friends truck was good.

My 10.3:1 compression 305 HO headed 350 TBI with mellings MTC-1 cam made 225 RWHP @ 3,800 rpm and 315 ft/lbs @ 2,300 which was the lowest the transmission would stay in 3rd gear(with a 6.2 diesel 3,800 rpm governor in it). I wanted to see what the torque was like and had the governor sitting around so, I got my numbers.

I haven't had much time for an update, so here it goes. Last week I added a set of 454 injectors, an open element air cleaner (unshrouded the TBI compared to a factory TBI van air cleaner), a K&N filter, and reworked the chip a little. While I was under the engine cover I found the #6 plug wire wasn't even on the spark plug as it was just dangling. One other thing was I changed the plugs to a set of AC Delco Rapidfires. I took it back to the 1/8 on Friday night. After letting it cool for about 30 minutes, my first run of the night felt real strong and netted a 79 mph trap speed but only a 9.95s with a 2.65s 60'. The next pass was my new best with 9.86 @ 76 with a 2.18s 60'.

Tuesday it was on the Mustang Dyno at school where it kicked out 267 rwhp @ 4,600 rpm and 335 ft/lbs @ 3,200 rpm. That was with a killer 11.6:1 air/fuel mixture due to a bad CTS(need to get a new one and change it). It could have been almost a full point leaner. We were checking emissions before my smog test this month and couldn't resist reprograming the dyno for a HP pull. By the way even without a cat it is very clean for a 1983 (could probably meet 1992 standards with a cat).

As a side note it is time for traction bars if I can only find some that will work with my rear end setup. My springs are over my axles and the only ones I can seem to find are for the springs that go under the axles.

Last week I was into this engine again. Dang valve cover gaskets were leaking. I did a running adjustments on the lifters and eliminated a couple of clicking lifters due to, too loose an adjustment. I also fixed the CTS issue by adding a new connector that actually would stay plugged in. I also changed the weights on the governor for a 4,800 rpm upshift to get me back into my power band. I have also been working on the tuning some more too. I have also added the CFM tech TBI spacer, stuck my powercharger back on it, along with a factory van air cleaner, and my K&N.

Friday night I went to the 1/4 and ran the following into a stiff 20 MPH head wind.

60' = 2.55s
1/8 ET= 9.853
1/8 MPH= 77
1/4 ET= 15.6s
1/4 MPH 87.6

This is the only run I got to do, due to the crowd there.

See the whole thread here

http://thirdgen.org/techbb2/showthread.php?s=&threadid=283217
1983 G20 Van, 350 TPI, Ported 906 Vortecs, Edelbrock 3817 Base, ASM oversize runners. Reed Custom Roller cam, 700r4, 12 bolt with 3.08 gears, Doug Thorley Tri-Y headers, true duals

Farmer Mike
Member
Posts 25
04-26-05 10:14 AM - Post#397033    

Excellent posts! G20, I've been reading about your successes in the 3rd Gen board. You've done a lot with the TBI system and it shows! I think the swirlport heads get a bad rap from the "experts". I kind of wish I kept them on but I might put them on a different project later...

I just got a different chip from Brian and while it's better than my old one, the truck is still far from running like it should. I have the data cable and WinALDL to do some datalogging. A good idea would be to send the results to Brian so he can do more fine tuning. At least until I read and understand basic chip burning concepts. I know why so many rip apart their TBI systems after trying to make their vehicles faster. It's pretty damn frustrating to throw $$$ at your motor and have it run worse than before. I just need to keep the faith and keep at it. I hope the rewards are worth the time/trouble.

Anybody else have some great results they'd like to share?

Mike
MikeJ
Moderator
Posts 4173
MikeJ
04-27-05 03:54 AM - Post#397034    

That information is SUPURB!
Mike


1983G20Van
Super Senior Member
Posts 3223
05-02-05 03:58 AM - Post#397035    

Just got back from a 1,200 mile road trip. With the cruise set at 75 and the A/C on I got 17.59 mpg for the trip. Keep in mind my engine is mild, I have 3.08 gears, and a 700r4. I am going to try highway mode at some point in time and get those numbers even higher.

As much as I like TBI I am probably going to switch to TPI for the increased torque down low where I like it. MAF TPI is the way to go!!! That system is basically self tuning.

I want to do the TPI swap because I have never seen one in a van. I have heard of one but never seen the pictures.
1983 G20 Van, 350 TPI, Ported 906 Vortecs, Edelbrock 3817 Base, ASM oversize runners. Reed Custom Roller cam, 700r4, 12 bolt with 3.08 gears, Doug Thorley Tri-Y headers, true duals

edothekid
Member
Posts 4
05-06-05 06:26 AM - Post#397036    

Hey guys, I just did a Vortec Head Swap to my 1993 GMC Yukon 5.7 TBI engine.

Everything went pretty smoothly. The Vortec Heads and GMPP TBI/ Vortec Intake bolted right up. We had to plumb the EGR supply tube from the driver's side header to the intake.

Other than the Heads, Intake, Gibson Headers and a TBI spacer and a Flowmaster cat back, the engine in completely stock.

Now, I need some help, Although the truck started fine, idles fine, we do have a problem, which I am not too familiar with. The engine needs some major tuning. I started it up yesterday, accelarated the engine @2,000 rpms for a few minutes and it accelarates very BAD. Not only that, but the headers start to glow. I was told by a few shops and tuning houses that it in running "gross lean". I am too much of a rookie to know what exactly that mean and how I could fix that, but I went ahead and got in contact with Brian at TBI chips. He responded very quickly and told me that I need to adjust the fuel pressure regualtor to 14 psi and run one of his custom chips for my application. He gave me a link on how to make the stock fuel pressure regualtor adjustable. The question that I have is, can I just buy and after market fuel pressure regualtor, install it and adjust it? If so, which would you guys recommend, and how easy is it to install it and adjust it?

Any info on how I could get my truck running, would be greatly appreciated.

Thanks again guys!

Edo.
1983G20Van
Super Senior Member
Posts 3223
05-08-05 11:36 AM - Post#397037    

Take the regulator apart, shim the spring with a washer rougly 1/8" thick and you are at about 14.5 psi on the stock regulator. You might be able to get away without the chip for the time being.

Also make sure that you have your timing set to 0* with the interupter wire disconnected. You could be really retarded on the timing which is adding to the heat and the stumble.

I have done 350 vortec TBI before in a C1500 shorty and all that was needed is 14 psi fuel pressure. The chip would be a nice plus but not mandatory.
1983 G20 Van, 350 TPI, Ported 906 Vortecs, Edelbrock 3817 Base, ASM oversize runners. Reed Custom Roller cam, 700r4, 12 bolt with 3.08 gears, Doug Thorley Tri-Y headers, true duals

edothekid
Member
Posts 4
05-09-05 04:48 AM - Post#397038    

Hey G20, thanks for the info.

I am going to do the pressure regulator mod to make it adjustable. I will let you know how the truck runs after the fuel pressure adjustment to 14 psi. I am going to also go ahead and order the chip from Brian at TBIchips and see how it works out.

The only question I have is about the timing. I did set the timing at 0, but what do you mean by "the interupter wire disconnected"? I am not familiar with this wire.

Thanks again, Edo.
1983G20Van
Super Senior Member
Posts 3223
05-11-05 03:18 PM - Post#397039    

The tan black wire that has the connector inline. You have to take the computer out of the loop or you will end up with -20 or so on the timing.
1983 G20 Van, 350 TPI, Ported 906 Vortecs, Edelbrock 3817 Base, ASM oversize runners. Reed Custom Roller cam, 700r4, 12 bolt with 3.08 gears, Doug Thorley Tri-Y headers, true duals

loudpedal
Super Senior Member
Posts 5010
06-03-05 09:57 AM - Post#397040    

I have just completed a project on a 5.7L TB piece that pushed the envelope to increase hp/tq on a budget without chip modifications and head scratching or kicking and screaming.

I will post below on this forum for those that are interested in seeing specifics.

"5.7L max motor mods with TBI and stock chip."
1983G20Van
Super Senior Member
Posts 3223
06-03-05 01:28 PM - Post#397041    

Well lets see it.

I know alot of you are stuck on the not reprograming part but to get the last chunk of power and to bring the combination togather, it has to be done. After tuning it felt like my engine was 50 hp and 75 ft/lbs stronger than before tuning. Gas mileage also improved remarkeably. It ran OK (got me to school and to work for a week on the stock tune). It ran alot better than a stock 350 TBI even on the stock tune. It would even idle at 500 rpm dead smooth without any hicups. Acceleration was still crisp but not smooth. I had alot of dead, surging, hesitating areas during WOT acceleration. It would make power but it would come and go. It would pull harder then let off a little then pull harder, back and forth. It would also surge for several seconds immediately after startup due to the larger cam. and increased airflow. It was about vortec 350 level performance on the stock tune. After tuning it felt like and would run with the 6.0 vortec. After datalogging and prom tuning it went from OK to K. A.

I just don't want you to be stuck with an engine that is not living up to its full potential. I see one on Ebay almost every week that is a 400 HP engine but the stock TBI EPROM is limiting it to about 320. Give it the proper tuning and it would be at 400 hp with the stock thorttle body and even intake.
1983 G20 Van, 350 TPI, Ported 906 Vortecs, Edelbrock 3817 Base, ASM oversize runners. Reed Custom Roller cam, 700r4, 12 bolt with 3.08 gears, Doug Thorley Tri-Y headers, true duals

loudpedal
Super Senior Member
Posts 5010
06-06-05 09:52 AM - Post#397042    

This is NOT a max efort piece as in high hp #'s BUT a max effort using STOCK TB, STOCK 5.7L injectors, and STOCK chip.


""""""I know alot of you are stuck on the not reprograming part """"""

...not only takes a lot of effort but a huge amount of time (and $$$) IF you use motor hardware that needs more of a fuel curve that can be supplied with stock TB/Chip.


"""""""but to get the last chunk of power and to bring the combination togather, it has to be done""""""

Sure, but you might only need so much power. In my case I calculated 300 flywheel hp would be enough and a TQ curve strong in the 2500-3500 rpm range.

You can max the motor eficiency at the running rpm /horsepower so as to use (and here are the parameters):

*Regular 86/87 R+M gas.
*Torque in the 2500-3500 rpm range (in my case pulling a 6 K # trailer)
*Keeping costs DOWN
*Using stock TB and 5.7L injectors
*Using stock chip
*Passing Calif bi-annual smog on the rollers as well as visual.
*Rataining iron manifolds.


The Pieces:

*A factory Vortec roller cam .420" x .410" exhaust fits in nicely for the torque curve, and at the right price (free) was irresistable. Straight up timing.
*World Products iron heads, equalized chambers and intake runners, 76cc x 1.940"I x 1.600"E
*.013" deck with flat top piston, .039" head gasket for 8.87:1 c.r.
*Adjustable fuel pressure regulator set at 11 1/4 psi.
*The other parts used & not mentioned only contribute to longevity and engine smoothness and not to combustion efficiency nor directly to HP increases. Well ok....the top rings at .018" and .002" piston to wall with low expansion forged pistons.

The tightest this motor will ever see is under 5k rpm...if that. The air requirements OVER that rpm would then necessitate a bigger TB supplying more air and more fuel pressure for the injectors, which then would reqiure chip modification. IF there was no heavy load pulling I feel that the c.r. could be bumped to about 9.6:1 and still use regular fuel and still the stock chip could be used. But I feel this is about the limit using regular fuel.

The motor seems very happy at 2 degrees BTDC and bumping the lead to 4 deg. seems to do nothing , and more lead might not be possible with a load.

The drivability is excellent as it also was with the stock 5.7L previously. The extra HP can be felt, exact numbers are unknown and I have only relative feeling from the flat lifter- stock TB head 1988 5.7L previously installed. Using calibrated seat of the pants it feels like about 50-75 horsepower more which is just what was needed.
1983G20Van
Super Senior Member
Posts 3223
06-09-05 04:39 PM - Post#397043    

You probably have an extra 30 hp over your NEW stock TBI engine. You very well could have 50 hp over your original high mileage engine. I would say you have the potential to get about 75 hp over stock with the correct tuning. The Worlds really aren't that much better than the 193s. Even though they flow marginally more they lack the high swirl properties that make low-speed torque. I have made 240 RWHP with 100% stock 193 heads and a mellings MTC-1 cam. The vortec cam has very simiilar specs to the stock 350 cam with the exception of having a roller cam.

I just don't like the idea of leaving 50 hp that I could have had as well as 3-5 mpg. My 355 with the LT1 cam was down almost 4 mpg on the highway before tuning vs. after. A little research and around $150 and I had the stuff to burn my chips. I did however have a laptop to begin with. I use turnerpro as it is shareware as well as WINALDL
1983 G20 Van, 350 TPI, Ported 906 Vortecs, Edelbrock 3817 Base, ASM oversize runners. Reed Custom Roller cam, 700r4, 12 bolt with 3.08 gears, Doug Thorley Tri-Y headers, true duals

Zoomy
Member
Posts 110
06-12-05 01:52 PM - Post#397044    

Ok;

Now for my 2 cents worth.

From all the posts Iíve read, they seem to be missing the mark on the original post.

My goal is to Max out Torque & MPG with external bolt-onís only.

Iím getting 22 mpg highway with the following mods: A 4x4 to boot
K&N air filter
MSD-6A
MSD Super Conductor Wires
NGK V-Power plugs Gapped @ .050
Jacobs Ultra Coil
Air intake silencer replaces with a 5Ē dryer duct.
Red Line Oil every where.

Future Mods:
Single Side cat-back exhaust.
See Gibsonís Web-Site, http://www.gibsonperformance.com/products-14297-swept_side_exhaust.html
Shorties.

Iím convinced any cam change will affect MPG for the worst.
I donít think a head swap is in order from the original post.
Would an intake swap be worth the gains?

Want the biggest bang for the buck?
How about a gear change in the order of 25% shorter.
This will greatly increase acceleration/towing with negligible effect on MPG.

Take it for what itís worth.
But, Iíve read some great info and have learned a lot.

Bill
Gibson
'72 Chevelle (3rd & 5th owner)
'74 C/10 Custom Deluxe
'94 Suburban-Given to Mom
'06 Suburban-Wife's Kid Hauler
'84 BMW 325e ... 300,000+ Miles, 32 MPG


1983G20Van
Super Senior Member
Posts 3223
07-03-05 07:50 AM - Post#397045    

Quote:



...not only takes a lot of effort but a huge amount of time (and $$$) IF you use motor hardware that needs more of a fuel curve that can be supplied with stock TB/Chip.






Alot of effort not really. Took maybe 20 hrs including research and the actual tuning to make a chip that was 95% correct. Then my Jimmy took less time than that.

It also does not cost too much. I can burn as many chips as I want now. To get started it cost for what one poorly matched aftermarket chip would. The expensive part is the EPROM burner at $85.00. I can now also chip as many TBI engines as I want for about $45.00 which is the Chip, Adapter, ZIF socket, and shipping. My invoice from Moates to do both my G20 and my Jimmy was $178.81.
1983 G20 Van, 350 TPI, Ported 906 Vortecs, Edelbrock 3817 Base, ASM oversize runners. Reed Custom Roller cam, 700r4, 12 bolt with 3.08 gears, Doug Thorley Tri-Y headers, true duals

mlrailguy
Senior Member
Posts 371
07-16-05 08:05 PM - Post#397046    

I have been watching this post also. I am only concerned about better mpg with my 4x4. Totally stock 92 GMC, 5.7, 700R4, 3.73, short stepside. It has plenty of power for daily driving, and not much problem pulling heavy load over the mountain. [once a year]
Just DUNE it

shotgun
Member
Posts 89
shotgun
07-19-05 04:06 AM - Post#397047    

Several posts mention cam changes. I know the factory cam is horrible, but at the same time my engine runs good and doesn't leak so I don't want to open it up.

What about installing a set of 1.6 roller rockers? That would be like getting a larger cam, plus the rollers would reduce friction and oil temps.

Also, a lot of posts mention the exhaust system. I'm hesitant about this, because I don't want a loud truck. Are there header and muffler combinations that would keep things fairly quiet while adding power?
scrambldcj8
Senior Member
Posts 1672
08-27-05 02:56 AM - Post#397048    

I would like to see more action here. I have a '94 5.7L K Blazer and I am going back and forth on buying a new(er) diesel p/u or just getting a trailer for my occasional towing needs....? I have owned it since day one and it is a northeast truck...only rust so far is on the doors lower edge. I have always rinsed out the door drain holes with my frequent washings.... and they still rust!!! It has since been repaired. I go between a new9er) truck with diesel and modding the '94. Mod options are a 383 with L98 heads (Vortecs you have to change too much for the gain IMO) because they bolt on and offer better breathing. I have also heard the TBI heads can be moddded easily for a sleeper head and actually work well when tweaked. Or, just rebuild the 5.7L, .030, L98's, good intake, good cam (?roller), and add TBI mods. I like the idea of slipping in a few extra cubes (383) though with only some minor fuel tweaking under all the existing components. Is that possible and have a smooth strong runner at the same time?

PS. Another option is to use the Hot Rod "The 350 Chevy Should Have Built" concept....Hmm?
scrambldcj8
Senior Member
Posts 1672
08-29-05 05:17 AM - Post#397049    

Just another thought. How would the TBI/ECM/ and all respond to a 400 short block under all the OEM stuff? Longer stroke and larger bore which helps to unshroud the valves leading better airflow. I would think one would just have to burn a chip and maybe use 9C1 injectors (or use an "Ultimate TBI" throttlebody....think that is what they go by?). Anything else?
ChopStixs
Member
Posts 11
09-10-05 07:35 AM - Post#397050    

Quote:

I have a similiar setup - 3" single exhaust, no cat, Flowmaster DF 40' series, and its too loud for me. Too raspy. Then again, things changed when i added a TBICHIPS.COM chip.

Would headers reduce the raspy "ba - ba - ba" upon acceleration? 350 TBI 5spd




Any cracking or "sparkler in a tin can" sound? Could be detonation.
scrambldcj8
Senior Member
Posts 1672
10-07-05 03:41 PM - Post#397051    

Just another option for "crate" motors:

http://blueprintengines.com/news/index.html?topic=details&news_id=31

5.7 Liter GM Stroker 383cid TBI
Cast iron heads, SCAT crank, Hypereutectic Keith Black pistons, Custom hydraulic flat tappet cam, Edelbrock Performer TBI intake and performance computer chip.
BP38301CT 280HP and 380 ft/lbs $3299
BP38302CT 315HP and 415 ft/lbs $3999
ArkansasDon
Member
Posts 5
ArkansasDon
11-26-05 03:00 PM - Post#397052    

I just replaced the old 5.7 to a 383 Stroker. I had it built at a machine shop and nothin rad, just a good strong 383 370 hp with a good strong 700R4 behind it. I'm still ironing a few bugs. I had comp Cams build a good mild cam with a chip to match, 9to1 flat tops,great heads with killer magnum roller rocker, ported & polish, JTI Shortie headers, Edelbrock Performer Intake with Holley EFI Throttle Body,Custom tuned Dual exhaust with 2 maga-flo cats and 2 full bore turbos 2 1/2" from the headers to the cats to the turbo mufflers to 3" turned down next to the spare tire. I'm happy with the changes I have made, tons of power and torque. Fuel problem now and thats resolved by a few after market parts fuel regulator and a larger fuel pump. Do your homework Superman 311, I have a great daily driver and the wife can still drive it without bein affraid of it. She calls it "The Problem Child" There is so many different ways ya can get more horses , someone suggested a chip, good call, nice exhaust, intake, Holley EFI, Shortie headers and still maintain your emissions. Money is a factor too, what ya want to spend and how to go about it.
Good luck to ya

heres a pic of my new motor, it only has about 150 miles on it

1990 GMC Z-71 383 Stroker Edelbrock Performer Intake Holley 650cfm Throttle Body JBA Headers Magna Flo Convertors Full Boar Turbo Mufflers

1983G20Van
Super Senior Member
Posts 3223
08-10-06 04:15 PM - Post#397053    

just had a nearly stock TBI engine dyno'd today. 177 HP @ 4,200 and 261 ft/lbs @ 3,600, the lowest speed tested. This engine has pulled over 320 RWTQ down around 2,300 rpm on a different dyno and in cooler weather. Keep in mind that the IAT readings were around 120-130* and the shop was 106* inside. The coolant was even above 200*. This is on E10 gasoline and in fully street legal form.

Stock 350 HD Shortblock (8.5:1 compression)
810 Swirl ports with light port cleanup
Stock Peanut 305 Roller cam with 1.6:1 roller rockers
1.5" x 3" flowtech cheapy headers
2.5-3" Y-pipe, Single 3" cat, 3" single in, Dual 2 1/2" out turbo muffler, dual 2 1/2" pipes
Edelbrock 3704 Intake
1" open center TBI spacer
Stock sized TBI unit with ultimate TBI mods
RBob's EBL with custom tuning
61 lb/hr injectors @ 17 PSI

This engine does everything that I need it to, including getting 15-17 MPG CITY!



1983 G20 Van, 350 TPI, Ported 906 Vortecs, Edelbrock 3817 Base, ASM oversize runners. Reed Custom Roller cam, 700r4, 12 bolt with 3.08 gears, Doug Thorley Tri-Y headers, true duals

Bishop
Frequent Contributor
Posts 1488
Bishop
01-28-07 10:33 AM - Post#1082020    

So from this whole post I am reading that you need a cam, intake, tbi pod, injectors, heads, headers, and a tanny kit to get good numbers to the wheels. I'm going to start work on my 5.7tbi this summer as soon as i get back home form school. The engine is out of a 1989 30 series van as well as the transmisson. I'm gonna list the parts below if you think you have a better match for me then let me know! or if you seem a problem with what I am going with also let me know I want to get this done right the first time so when I drop the engine in the truck all I have to do is make minor adjustments and go (although i doubt that will be the case). I have almost any tool I will need, I have a mandril pipe bender to do my own pipe work, and I have all the tools needed for ports and polishes.

Cam: Melling MTC-1 cam kit from Autozone
Intake: Edelbrock Performer TBI bored to 2"
Pod & Injectors: 454 TBI pod with injectors
Heads: Iron L-98 heads port & polish
Exhaust Manifold / Headers: ? any ideas?
Exhaust Pipes: 2.25" dual with H pipe
Mufflers: no clues here Dyna Flow? any suggestions are welcome, I want a nice deep sound that is loud but not to loud.
Transmission: I dont know what kind of transmission I have, how do I find out and once i do what mods should I do to it?


Thanks for all the help in advance, with everything that I am doing I know it's gonna cost a pretty penny but I want to keep my costs down as much as possible.
Not only so, but we also rejoice in our sufferings, because we know that suffering produces perseverance
Romans 5:3

scrambldcj8
Senior Member
Posts 1672
02-02-07 07:05 AM - Post#1085839    

From my discussions with 1983G20 I would ditch the 454 TB and keep the 350 TB and run either higher fuel press. or slighty bigger injectors....or both if needed but I doubt that'll be the case. The 350 TB will flow enough air and per 1983G20 these motors are generally fuel limited and not airflow limited. Also, the 454 TB takes some changes to hook it up besides the boring of the intake.

EDIT: The tranny from that 89 should be a TH700R4.....AKA a 4L60 (without the "E" as it is not electronic).
1983G20Van
Super Senior Member
Posts 3223
02-10-07 06:24 PM - Post#1093062    

Good advice overall

The 1989 1 ton van transmission is more likely a TH400.
1983 G20 Van, 350 TPI, Ported 906 Vortecs, Edelbrock 3817 Base, ASM oversize runners. Reed Custom Roller cam, 700r4, 12 bolt with 3.08 gears, Doug Thorley Tri-Y headers, true duals

Bishop
Frequent Contributor
Posts 1488
Bishop
02-10-07 06:38 PM - Post#1093079    

i dont think is a th400, th400's have 3 forward gears, this one has overdrive, so i think it's a th700R4
Not only so, but we also rejoice in our sufferings, because we know that suffering produces perseverance
Romans 5:3

scrambldcj8
Senior Member
Posts 1672
02-12-07 09:00 AM - Post#1094275    

1983G20, glad to see you're still around. I am also glad this post hasn't died.....I am still tossing around that notion of sliding a 400sbc under my 5.7L TBI components and keeping things on the mild low rpm TQ side.
1983G20Van
Super Senior Member
Posts 3223
02-12-07 10:06 AM - Post#1094334    

Yeah, I am still around, just troll here more than anything. I post ALOT on Fullsizechevy.com and Thirdgen.org, just stay too busy to post much on here.

I have done some work to my TBI setup, including running it on a late model GM Mass Air Flow sensor. Runs awesome. Ported 305 TPI heads, ZZ4 roller cam, 46mm TBI unit, 1 3/4 primary headers, 2 1/2" duals, 2,600 rpm converter, etc. Picks my 5,300lbs Van up to 80-90 effortlessly.

Ported 081 TPI 305 heads, Ebay sourced ZZ4 cam, Edelbrock 3704 intake, 1" open center TBI spacer, 46mm bored TBI unit, 350 injectors at 36 PSI, TPI pump in the tank, Long-tube headers with 1 3/4" primaries, Dual 2 1/2" exhaust, Late model TBI PCM installed with an 85mm GM MAF sensor from a 5.3 truck, 700r4 built up with a 2,600 rpm Yank converter, 3.07 gears, P295/50/R17s on 17 Impala SS rims.










Just so we know that this is NO BS.

Keep in mind that I have 3.07 gears and the speedometer gears are for the 3.73s that I recently destroyed. That means the speedo is 10-15 mph slow at all points. 5,000 rpm in 2nd gear with 3.07 gears and 29" tall tires is roughly 100 mph, that is with no converter slippage, with converter slippage figured in, I got up to about 90 or so.

This run was 2/3-3/4 pedaled from the start all the way until it downshifted 3-2 again at speed. Keep in mind that it may look slow, but the traffic is moving an easy 80 mph on this stretch of ramp. Notice the 2nd highway sign go by. WOT in 2nd took me up to about 80-85 mph, crested 90 once I got moved over into the next lane. 75 showing on the speed = 90 in reality

http://www.youtube.com/watch?v=GeyY5UZ0V6I

WOT to about 60 in 1st

http://youtube.com/watch?v=koWaPeAu3hg

A little part throttle run

http://www.youtube.com/watch?v=c6qV9T7ZCOI

A top-end run on a day with very light traffic. Top end was roughly 110 before I ran out of road and had to slow down.

http://www.youtube.com/watch?v=e3bfNJYT1I4

The rattle in the back, is the tools in my small toolbox in the back.

http://www.youtube.com/watch?v=e3bfNJYT1I4

Cold Idle

http://www.youtube.com/watch?v=wRehD8He18E

Cold Start, Idle, light rev, audio sync is way out courtesy of YouTube.

http://www.youtube.com/watch?v=FmS1m3zlqHo

1983 G20 Van, 350 TPI, Ported 906 Vortecs, Edelbrock 3817 Base, ASM oversize runners. Reed Custom Roller cam, 700r4, 12 bolt with 3.08 gears, Doug Thorley Tri-Y headers, true duals

Bishop
Frequent Contributor
Posts 1488
Bishop
02-12-07 10:56 AM - Post#1094373    

nice van, can you give me some advice for the 350 i'm putting in my truck? I want to do intake, cam, heads, exhaust, computer. what do you recommend for all of those and what little things can i do the exsisting parts to get the most out of them? the 350 is on an engine stand right and i have a TH700R4 to go along with it, are there any moderatly priced mods i can do to the tranny make it stiffer and alot more efficent. I want an engine that pulls like a truck should but i aloso want it to have some speed as well, the engine and tranny are both from a 30 series 1989 chevy van.
Not only so, but we also rejoice in our sufferings, because we know that suffering produces perseverance
Romans 5:3

chevy355s10
Frequent Contributor
Posts 1126
chevy355s10
01-14-09 09:12 PM - Post#1607274    

is axelrod ever gonna tell us what it dyno'ed at?
David B.

clark31
Forum Newbie
Posts 80
04-23-09 12:04 AM - Post#1683002    

OnAllFours I was wondering if you ever got that audio file of your exhaust?? I want to hear it


Axelrod did you do that dyno and whats the results?
1989 Chevy Suburban 2wd r1500 with 5.7L 350sb tbi and 700r4 (mods) are 'Headman' long tube headers,3" y-pipe, magnaflo high flow cat and super 44 flowmaster
2005 GMC Yukon Denali XL

evot123
Contributor
Posts 210
04-24-09 06:26 PM - Post#1684399    

on my 90 z71 i rebuilt a 97 vortec short block, light weight vortec pistons .030 over, stock vortec roller cam. used my factory tbi heads and installed a hypertec chip, true dual exhaust and mine has plenty of power......mike
dont give up, help is on the way

someotherguy
Moderator
Posts 25471
someotherguy
09-19-10 08:30 AM - Post#1978048    

This thread has been dead a while, probably all the bases have been covered but someone reading it recently seemed to feel that a lot of the mods were for extreme power and not just everyday driver improvements. With that in mind I rattled off a quick list that IMO sums up easy and fairly inexpensive mods for the TBI engines:

Mind you the post says "big block" but the original thread was about swapping a big block in for more power; it derailed into making more power with the existing small block without going crazy.

http://www.chevytalk.org/fusionbb/showpost.php?pos...

Post contents:

Eh; there's some hardcore info in there, but the main purpose of the thread (at least in the beginning) are mild mods for regularly driven trucks.

Here's what I can come up with just off the top of my head, for fairly tame mods that can improve power, without breaking the bank or making your truck unreliable for daily driving:

I recall a mild cam grind (MTC-1?) that offers a little more performance but won't affect the computer.

Headers are worth some power but not really necessary for low end.

A GM "369" ignition module offers a better ignition curve than the "048" module. Even better would be the Performance Distributors "Dyna-Mod" module. *

Advance base timing to around 4 degrees; you might try a little more but be VERY careful to listen for pinging. If it pings at all under load, back off the timing a bit. *

Swapping heads out is pretty expensive so I'd leave that alone unless you're really going for a substantial gain.

Pull out the somewhat restrictive portion of the air intake ductwork that sits inside your passenger fender on the 88-93 models. This piece runs horizontally inside the fender, over the wheel opening. Has a single 7mm screw near the side of the battery, and a clip fastener inside the opening where you remove the flex tube to the air cleaner and its plastic adapter to the fender. You'll have to snatch the ductwork out with pliers, it's in there good but it's semi-flexible. You'll still have the factory cold-air induction for what it's worth, it will just be less restricted. *

If you don't have emissions checkups, pull the heat riser flap assembly out of the air cleaner housing and fashion a patch to cover the opening. When the wax pellet in these fail from age, the flap can stick or suck closed, causing restriction. *

Replace air intake silencer box with a full straight flex tube from a base model V6. *

Modifying the TBI unit's internal fuel pressure regulator to increase pressure may show some gains, may not.

Replacing the injectors with higher pound-per-hour units from a Caprice TBI 5.7 engine complements the adjustable fuel pressure mod. If you can get the injectors used in good shape, you're winning - if you buy them new, expensive.

High-flow catalytic converters are a little bit pricey but something to consider if yours is original and needs replacing. Of course gutting the cat is highly illegal, but some people do it anyway. *

A good muffler can help too; some argue that Flowmasters don't flow really well but I believe it's marketing hype from other brands. Some people like Magnaflows. I personally love the loud tone of a Flowmaster 40. *

If you haven't made other significant improvements, I'd leave out the expensive Edelbrock Performer TBI manifold, and the Holley replacement TBI unit. $$$$

Working with a chip provider and letting him know exactly what you changed goes a long way to realizing the performance gains.

There's some suggestions for daily-driver mods you can do, just off the top of my head. Most of them are low-cost and some even free.

Of course, be sure the complete engine is in the best state of tune you can get it, using quality parts. *

* Stuff I have actually done to my truck. I'll also perform the other mods as time/money allow, and maybe a step further.

Richard
94 C2500LD / 94 C1500 / 06 300C SRT8
Check out my truck shop projects

hillrod420
Forum Newbie
Posts 5
09-19-10 11:21 AM - Post#1978107    

I'm new to this site, seen a lot of good info & some conflicting views of reality, nice thread overall. I also have a '93 K15, ext cab & 350 that started off back in 2000 when I got the truck from my dad who babied it till 115K, Let the games begin!!!
I started off with the exhaust that was about to fall off, cut off the 50# cat & installed a flowmaster 3" in & dual2.5" out & then got ahold of a used Hypertech chip that made it shift better but much of a noticeable power increase, (it is a 5000# beast though). I did however notice the mileage drop about 2 MPG & had to run premium fuel, oh well. As already mentioned in a previous post the underdrive pulleys gave a little power from not turning the heavy fan but did burn out alternators left & right cause it turned too slow & wouldn't charge so I took them off!!!
I them acquired an Edelbrock Performer TBI intake & 1.6 ratio rockers & noticed a little power in the passing gear area & it revved out to the 5000 rpm rev limiter MUCH quicker. Fuel mileage seemed to stay the same 15 MPG.
The exhaust has rusted out & falling off again now in 2008 so I put in ceramic coated mid length headers, had to extend O2 wire to reach, 2.5" true duals with some Summit version Flowmasters, ($30 compared to $80). That gave it a little bit more power, maybe 20 HP,(already had the Flow muffler to start with)
I then found a Performer RPM intake for $50, made an adapter for the 2" 750 cfm TBI & adjustable fuel pressure regulator to bolt onto the carb intake, as a 2" spacer. It had a little more low end torque but Holy Hesus did it come to life from 2500 ON UP!!! That gave it a good 50 HP!!! If you can get that intake & adapter for a good price snag it up. I also noticed the mileage come up to 17 MPG now at 250K miles, stock cam, heads, & short block, will beat vortec trucks, AWESOME!!!
I should have stopped there, got greedy, found a good deal on a 383, ported camel back heads, balanced short block just needed freshened up. Cam was too big had to switch to a carb for a while, that was one long year & a half with a carb!!! My good deal 383 piston came apart & I'm putting together a 400, 6" rods, flat top Keith Black Hypereutectics, the same camel back heads with a comp cams 262-270 with .464"-.470" lift, recommended by TBI chips .com for a usable vacuum range for a tbi chip. If this 400 don't pan out I'm gonna cut my losses & go back to the old 350, port them swirl heads with the same cam & long rods for more torque!!
I need to put the bigger fuel pump in the tank & fix that gas leak at the same time before throwing that new tbi motor in the truck. I also need to find the equipment to burn my own chip since I'm most likely NOT gonna leave it alone forever. Found one place that wants about $300 for their "kit", any info on were to find one at a reasonable price let me know, I'm look'n.
Hopefully we can hear back from Axlerod on his dyno project. Happy wrench'n ya'll!!
Axelrod
Senior Member
Posts 876
08-12-11 09:30 AM - Post#2124857    

I never followed up with another dyno run because I ended up staying 'stock' until a complete rebuild at approx 140k. I ended up going the stroker route with a .40 overbore (385c.i.) and bumped the compression up to 9.25:1. I had a set of iron L98 TPI heads that had already been freshened up, (including porting, polishing and cc'ing), along with a Speed Pro 'RV' cam, and an Edelbrock TBI intake that I purchased but never installed. I haven't fired it up yet, so I can't comment on how well it runs, as I am still in the midst of paint and final assembly. I do plan to do another dyno run and will post the results here afterwards. It won't be in the next couple of months tho' at the rate it's going.


dirtgod1
Contributor
Posts 223
dirtgod1
08-12-11 11:03 PM - Post#2125055    

Hurry up with this build!! That engine/frame alone is making me jealous haha
'92 K1500, favorite car I've ever owned
'63 Jeep j100 with all Chevy guts
'93 Mazda b2200 ( piece of s#%@!)

king_alcohol
Contributor
Posts 372
king_alcohol
01-12-12 12:55 PM - Post#2178598    

What an awesome thread!
bump
1966 C10 short fleet Custom, 402ci, 700r4, 3.73, dropped, bagged, factory air
1992 Suburban 1500, 4wd, 350ci tbi, 228,000 miles and counting
1959 Biscayne 2door, not running, but rolls nice
1964 C10 carryall, project

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