I have a couple questions and figured id turn to the pros.

I plan on buying subject Suburban this weekend. Its a 95 TBI injected 454 K2500 Suburban with a whipple charger.

1. What kind of HP can i expect assuming this setup is using the stock (90 lb/hr stock?) injectors.

2. What is the potential of this setup? I have to imagine the TBI injection will be easily overpowered by a supercharger at even low boost levels?

3. If my assumptions are correct (not enough fuel for big horsepower) what can be done to achieve 400 hp fuel system-wise assuming i want to keep the factory TBI style system?


My reading on this site tought me that this truck will have the prefered PCM for editing so that's a plus. I just dont think i'm giong to be able to pull the most HP out of this setup with only 2 injectors that are probably at most 90 lb/hr each??!?!! Am i mistaken?


thoughts?

 

21 views and no one?

 

i think its because this a camaro firebird third gen forum

 

basically. I have no information to tell ya. I know a lot of people come here because this site has some of the best technical advice on the web about anything TBI related.

 

Exactly... many many people on this board are NOT 3rd gen owners... this board has a ton of TBI info though which is why many come.

 

The stock injectors are 46 #/hr at 13 psi. With GM running them at 30 psi for a flow of 75#/hr per injector.

For the HP that can be had, take the stock HP rating and multiply it by the boost divided by 14.7 . Then add the result to the stock HP rating. Note that this method doesn't take into account inefficiencies in the system.

It is just a ball park number.

From that calculate the amount of fuel required for that HP level. I would use .55 BSFC as it is a boosted engine (and most likely under 12 psi of boost).

I take it the truck is an auto, not a stick?

RBob.

 

Awesome this is a great start... I have bought the truck and yes it is an auto 4l80e. Current boost is only ~4psi.

Truck has a zeitronix wideband. It is running quite lean at throttle tip in (15, 16, 17:1...very bad) until the pcm decides it ought to add fuel...at that point AFRs come back down to the 11-12:1 range under boost.

Is there a way to bypass the stock fpr that's attached to the TBI unit? Id like to bypass it completely and run a aeromotive 1:1 rising rate adjustable unit.


thanks

 

I did just that. I used the base to cut a gasket from material I purchased from an auto parts store. I used same base to scribe a alum plate from stock. cut to shape with a dremel. That went in place of stock FPR. Then plumbed in the Aero unit downstream of TB.

Does not whipple use a Fuel Management Unit(FMU) to avoid tuning?

You may need to determine what fuel pump in in truck and possibly upgrade.

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Thats exactly what i want to do.... how did you plumb your inlet/outlet lines? Which FPR did you use?

 

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All lines Aeroquip push fit and same on adapters.

Aeromotive 13301(??) VAFPR (supports boost)using low pressure spring (1-20) provided set to 20 lbs currently but may need to swap in high pressure(20-60) also provided and move FP to 25 lbs to support N20 install done late last tuning season.

 

Hard to see your plumbing.... so im guessing fuel supply from pump/tank goes to inlet of TBI unit... outlet/return line from TBI unit goes to inlet of FPR.... return from FPR goes to tank return?

Is this how you did it?

 

YES. sounds right.

This is a 84 Corvette. Right next to AC compressor we cut both feed and return lines. Aeroquip sells a NPT compression fitting with female end. That is important! Note then an Aero NPT to AN female. Then the push fit barb straight to AN male. That you can see. Other side I believe to be same. Bottom of Aeromotive FPR is the return to tank. Fortunately for me is a Aeroquip distributor nearby. I bought excess fittings not knowing how it would shake down and returned to them unused ones.

This summer I used an unused port on FPR and added the feed from N20 solenoid. That worked well.