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Username Post: Selecting a stock-ish in-tank pump        (Topic#351425)
cloudmaster 
Senior Member
Posts: 1008
cloudmaster
Loc: Arrowsmith, IL
Reg: 01-30-02
06-04-18 11:58 AM - Post#2735905    

So, I have a factory '87 Chevy truck sender in an '87 tank feeding the (TBI Holley HP EFI) 454 in my '85 C20. When I set this up the first time a couple of years ago, a faulty valve spring broke during idle tuning, leading to catastrophic failure. I just got the engine back together and installed, but then yesterday when I went to start it for the "second first time", the fuel pump has died.

Thinking about it, that Spectre "stock TBI 350" pump probably isn't enough to feed a 550-ish HP big block anyway. When looking at more appropriate replacement pumps, though, everyone either suggests a "Walboro 255" or maybe an "Aeromotive 340". But there are half a dozen 255Lph Walboro pumps - some of which aren't even in-tank models, and Aeromotive must have used a time machine to find the web developer responsible for their web site. :D

I assume the Walboro everyone is talking about is the GSS342, but it doesn't sound like it's super reliable. I'm guessing Aeromotive is either the 11540 or 11541, but again, not positive (though I do have better feelings about Aeromotive overall). I really just want something that will fit the stock hanger without me having to fabricate much beyond the electrical connector, and one that might actually last. Can someone point me in the right direction?

'71 Malibu: 350/200-4R/3.73 Eaton posi
'75 Elky: 350HO/TH350/3.42 peg leg
'85 C20: EFI454/TH400/3.73 locker
'95 Caprice Wagon: LT1/4L60E/3.42 posi
'04 Grand Marquis: 2V4.6/3" pipes/SCT flash


 




Rick_L 
Honored Member
Posts: 27644
Rick_L
Loc: Katy, Tx, USA
Reg: 07-06-00
06-04-18 02:45 PM - Post#2735918    
    In response to cloudmaster

The Walbro GSS340, GSS341, and GSS342 are rated at 255 lph. Claim they will support 500 hp, don't know where that leaves you with 550 hp - whether there's enough reserve there.

The difference between the 340, 341, and 342 is the location/orientation of the fuel pickup. What you want is one to match the inlet style that your truck used.

Aeromotive has 3 similar pumps but they are rated a little higher. You may need to change the wiring for the pump to a bigger gauge because of that. (Might be true for Walbro too, since your stock pump is low pressure.)

Curiously I've heard the Aeromotive pumps are less reliable than Walbro.



 
cloudmaster 
Senior Member
Posts: 1008
cloudmaster
Loc: Arrowsmith, IL
Reg: 01-30-02
06-05-18 05:07 PM - Post#2736073    
    In response to Rick_L

Looks like around 11 amps tops for the Walboro, and I assume similar for the Aeromotive (since it's supposed to be a "stealth stock replacement"). At 14.4 volts, that means surprisingly tiny little 20 gauge would just barely be able to maintain 12 volts at the pump ten feet away - though you'd justifiably get some sideways glances if you did that. I ran 14 gauge off an individually-fused relay when I rewired everything (technically just "wired", since there was no pump there stock), so that part should be ok.

'71 Malibu: 350/200-4R/3.73 Eaton posi
'75 Elky: 350HO/TH350/3.42 peg leg
'85 C20: EFI454/TH400/3.73 locker
'95 Caprice Wagon: LT1/4L60E/3.42 posi
'04 Grand Marquis: 2V4.6/3" pipes/SCT flash


 
grumpyvette 
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 17382
grumpyvette
Age: 71
Loc: FLORIDA USA
Reg: 03-16-01
06-15-18 11:44 AM - Post#2737051    
    In response to cloudmaster

http://garage.grumpysperformance.com/index.php?thr...

IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!


 
cloudmaster 
Senior Member
Posts: 1008
cloudmaster
Loc: Arrowsmith, IL
Reg: 01-30-02
04-19-19 09:43 AM - Post#2764581    
    In response to cloudmaster

Sorry to pull this post back from the dead, but I thought for the sake of anyone searching...

I ended up getting the Aeromotive 340 pump. Specifically, the Aeromotive 11569. I reused the Spectra hanger (1 and 2), and spliced the pump's weatherpack-ish connector into the sender/hanger's passthrough wiring. So it looks all "stock" outside, and fit inside really nicely (though I did have to trim the bottom isolator a little). It actually worked out really well, and I've been super happy with it. It's just barely loud enough that I can tell it's working when it's quiet out, and easily feeds this engine.

Of note, though, the pressure exceeds the capability of the dual fuel tank switcher on this'85 truck, so when you kick on the pump, it overrides the switch's pressure bypass and starts blowing fuel out of the switch onto the ground.

So, I've been using just a single tank for the time being, but I'm working on an Arduino-based solution to watch the sender level in both tanks. When the "main" tank gets to about 1/2 (because the gauge is most sensitive in the center of the sender's travel), it'll periodically trigger the electric pump in the second tank to kick on and transfer fuel over through the unused evap canister fitting, maintaining the main tank at roughly "half" until the secondary tank goes below about 1/4. When the main tank starts going much below half, I know that it's time to fill both up. I still need to figure out how I want to trigger an "emergency" mode that will transfer over that last 1/4 tank (maybe a "dump the spare tank" switch? Maybe automatic if main goes below 1/4?), and also figure out if it's worth the time to implement a "gas station" mode where the secondary pump runs constantly (or until main reads "full", I guess) while I fill the secondary tank to also partially fill the main tank. But there's always a new project. :D

'71 Malibu: 350/200-4R/3.73 Eaton posi
'75 Elky: 350HO/TH350/3.42 peg leg
'85 C20: EFI454/TH400/3.73 locker
'95 Caprice Wagon: LT1/4L60E/3.42 posi
'04 Grand Marquis: 2V4.6/3" pipes/SCT flash


 
65_Impala 
Very Senior Member
Posts: 4241

Reg: 12-29-02
04-26-19 09:53 AM - Post#2765083    
    In response to cloudmaster

C5 and C6 Corvettes use a siphon or jet pump to transfer the secondary tank to the main tank. Basically, the return line passed through the secondary tank when it goes through an orifice or jet pump which picks up some of the fuel from that tank. It then continues on to the main tank resulting in the return line bringing back more fuel than what the pump sent out. The Vette tanks are linked by a common filler tube at the top so once the jet pump has filled the primary tank any excess fuel being brought over just runs back to the secondary tank through the filler pipe. Also, nothing has to be done when the secondary tank runs empty, the jet pump just sucks air.

It's more complicated plumbing wise but still maybe you could build something similar. It's quite a simple system which just works without any intervention or electronics or electric pumps involved.



 




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