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Username Post: TBI Cam        (Topic#348441)
dbwinburn 
Infrequent Contributer
Posts: 32

Age: 39
Loc: IRMO SC
Reg: 02-04-12
11-28-17 04:50 AM - Post#2716054    

So I’ve got a crate motor to replace the blown 5.7tbi in my blazer. It’s got vortec heads performer intake 46mm tbi headers and dual exhaust. cam is.495/.503 lift 220/224 duration 110* lsa. To me that doesn’t seem wildly aggressive but I’m being told by the programmer that the vacuum will be too low to control the fuel.
Just looking for some expertise here. Is it impossible or just tricky to get the chip burn correct? I don’t want to carburate this and have way more money wrapped up in this truck than it to ever be worth.
So what are my options here?
Thanks guys



 




65_Impala 
Very Senior Member
Posts: 4031

Reg: 12-29-02
11-28-17 05:30 AM - Post#2716056    
    In response to dbwinburn

It should be tunable. More LSA would likely have been better. Which ECM?



 
dbwinburn 
Infrequent Contributer
Posts: 32

Age: 39
Loc: IRMO SC
Reg: 02-04-12
11-28-17 11:56 AM - Post#2716102    
    In response to 65_Impala

It’s a 93 K1500. Delco 2plug ecm? I could get the #s off it if needed. Prom code is BDJY.



 
65_Impala 
Very Senior Member
Posts: 4031

Reg: 12-29-02
11-28-17 03:48 PM - Post#2716139    
    In response to dbwinburn

It's a good PCM to start with. If it was older, I would have suggested upgrading it to a faster more capable PCM but you're already there.





 
Rick_L 
Honored Member
Posts: 27388
Rick_L
Loc: Katy, Tx, USA
Reg: 07-06-00
11-28-17 10:30 PM - Post#2716219    
    In response to 65_Impala

Thing is, you're going to need to tune for it to run right. I think your ecm is one that uses a chip. So to tune you'll need a new chip programmed by someone who does that sort of work. You'll have to get a chip programmed for each tuning iteration. Or replace it with a flash memory chip, and get some software and a cable so you can do it yourself - then it can be tuned many times.

Careful choosing a tuner/chip burner so it's right or close the first time.



 
dbwinburn 
Infrequent Contributer
Posts: 32

Age: 39
Loc: IRMO SC
Reg: 02-04-12
11-29-17 04:51 AM - Post#2716228    
    In response to Rick_L

I think the first guy I talked to didn’t want to deal with multiple burns so he blew me off. I sent my info to Sinister performance to see what they say. I’ve also looked at the flash ecm but the ones I’ve seen don’t run e-trans. I’ve also been looking at Moates for hardware. My main thing is how bad that cam is gonna hurt me



 
65_Impala 
Very Senior Member
Posts: 4031

Reg: 12-29-02
11-29-17 12:09 PM - Post#2716257    
    In response to dbwinburn

Dynamic EFI doesn't make a flash conversion for a PCM. So, no transmission controls from them.

Moates has an emulator that should work with and it is even better than flash because you can tune in real time with the engine running. But, it does require a new chip is burned once the tuning is done.

I wouldn't count on a mail order tune to be very accurate unless the tuner does multiple iterations for you.

There are a few tuners around that will connect through a remote desktop to the computer connected to the emulator and do tuning remotely. Try posting at gearhead-efi and asking if there is a tuner who would help out.

Learn the transmission tuning at the same time, You can really change how a vehicle drives with transmission changes. Stock, GM loves to set tunes to upshift early and require lots of throttle for downshifts. Modifying the shifting to hold-off on the upshifts a bit and to downshift quicker will make a big difference in how the truck will drive.



 
Rick_L 
Honored Member
Posts: 27388
Rick_L
Loc: Katy, Tx, USA
Reg: 07-06-00
11-29-17 12:10 PM - Post#2716258    
    In response to dbwinburn

You didn't say what you had for a transmission. If it' an automatic, you may need a higher stall converter to make it all work right. Even a mild 2000 stall converter would make this deal work a lot better.

My other concern would be the small throttle body. Your cam is taking away low speed performance, and the small TB would take away from high speed performance. A stock TBI runs out of beans at 4500 rpm or so, part of this is the TB, the rest is the small cam the stock engine uses.



 
1983G20Van 
Super Senior Member
Posts: 3700
1983G20Van
Loc: Bedford, Texas, USA
Reg: 11-13-02
12-13-17 03:24 PM - Post#2717829    
    In response to Rick_L

  • Rick_L Said:
You didn't say what you had for a transmission. If it' an automatic, you may need a higher stall converter to make it all work right. Even a mild 2000 stall converter would make this deal work a lot better.

My other concern would be the small throttle body. Your cam is taking away low speed performance, and the small TB would take away from high speed performance. A stock TBI runs out of beans at 4500 rpm or so, part of this is the TB, the rest is the small cam the stock engine uses.



46mm TBI unit is good for something in the 330-350 HP range before it becomes a restriction. It flows better than a 500 CFM Holley 2-barrel and I have seen more than one car run down the track in the mid-low 13 second range with a 500 cfm 2-bbl.

That being said the cam in that engine is completely tuneable. It was probably TBICHIPS.COM that told the OP it would not work! I have run the Blue/Red TBI PCMs with Multipoint injection and 232/240 @ .050 on a 110* LSA with near factory driveability. That cam is not really enough to take away much if any low-speed torque. Once you get above about 224 @ .050 on the intake is when you really start to notice low-end going away. I have a L30 305 Vortec in a 1999 Tahoe that has a Lunati 218/218 @ .050 cam cut on a 110* LSA and even when it had the stock 1,600 rpm stall torque converter in it, the thing came alive and pulled strong even from a dead stop.


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


Edited by 1983G20Van on 12-13-17 03:26 PM. Reason for edit: No reason given.

 
dbwinburn 
Infrequent Contributer
Posts: 32

Age: 39
Loc: IRMO SC
Reg: 02-04-12
12-19-17 11:17 AM - Post#2718436    
    In response to 1983G20Van

Thanks. That is who told me but I think I’ve got sorted out. Now all about stall. Tires 33.8”. Gears are 456. The chart I have shows about 2100rpm in 4th gear @65 mph
Engine calls for 18-2200 stall. I know weight (6100 gvw) and gears play a part in actual stall and I don’t want to end up slipping at cruising speeds so what would you say the ideal converter would be?



 
dbwinburn 
Infrequent Contributer
Posts: 32

Age: 39
Loc: IRMO SC
Reg: 02-04-12
12-19-17 11:29 AM - Post#2718437    
    In response to dbwinburn

And thank you guys for sharing your time and knowledge



 
raycow 
Honored Member
Posts: 27574
raycow
Loc: San Francisco, CA
Reg: 11-26-02
12-19-17 09:54 PM - Post#2718500    
    In response to dbwinburn

  • dbwinburn Said:
.....I know weight (6100 gvw) and gears play a part in actual stall and I don’t want to end up slipping at cruising speeds so what would you say the ideal converter would be?


Any converter that doesn't have a lockup clutch will slip "some" at cruising speed, so the ideal converter would have a clutch. A lot of people refuse to believe this until they see it on a tach. Unfortunately, you didn't say what kind of trans you have, so I don't know if it will support a lockup.

Ray

Those who choose an automatic transmission want transportation. Those who choose a manual transmission want to drive.


 
dbwinburn 
Infrequent Contributer
Posts: 32

Age: 39
Loc: IRMO SC
Reg: 02-04-12
12-20-17 08:44 AM - Post#2718548    
    In response to raycow

Sorry thought it was in original post but it’s a 4l60e. Freshly rebuilt



Edited by dbwinburn on 12-20-17 08:50 AM. Reason for edit: No reason given.

 
raycow 
Honored Member
Posts: 27574
raycow
Loc: San Francisco, CA
Reg: 11-26-02
12-20-17 10:01 AM - Post#2718557    
    In response to dbwinburn

Then you are good to go with a lockup. Slip at cruise will be a non-issue.

Ray

Those who choose an automatic transmission want transportation. Those who choose a manual transmission want to drive.


 




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