Jack, I'm most likely going to come see you and ARE in Feb or so for a new fuel pump.

2hrs is a deal to do the work.

THanks for the heads up on the labour time.

 

After having recently performed a FP replacement on my truck (which is much easier than an F-body!) and reading Jack's post about the Racetronic's walbro pump and kit, I would tend to agree that their kit would be better. I like their flexible hose

94bird, having an AFPR enables one to better dial in the appropriate amount of fuel PSI and a higher flow FP on a modified engine. This doesn't imply that ECM/PCM programming changes aren't necessary or important.

 

there is lots reasons to do and not do it
the link to the guide is in this post:

http://web.camaross.com/forums/showt...ss+panel+guide


lots of good info there.
jesse

 

Thanks for the heads up

 

why do you need FPR if the computer would just compensate for it and change the pulswidth of the injectors?

 

The pcm's range is not unlimited.

 

I guess I would disagree. I would tune the computer instead of adjusting fuel pressure. It's just the better overall solution.

 

if you have the right injector.

which would be better:
1. 24# injectors, fuel pressure at 58psi, injector constant programmed at 30#
2.30# injectors, fuel pressure at 40psi, injector constant
programmed at 30#

the same amount of fuel would be delivered right?

jesse

 

The 30# injectors at 43.5psi... as they were flowed and rated at that pressure.

Adjusting pressure is obviously one way to make the injectors flow more fuel, and yes I'm aware of the general rule of thumb regarding pressure and flow rates... but if you go with an AFPR, make sure you either a) get the injectors flowed and b) program the injector constant to compensate (as you mentioned).

The reason many avoid the AFPR is the somewhat "unreliable" reputation the cheaper units out there have built.

Personally I feel safer with a GM unit designed to be at 1 specific differential, instead of one that can change it's calibration. Done right, either is fine... but eventually the AFPR won't be able to compensate (assuming future hp gains), so you might be further ahead just to get larger injectors now and shoot for a low 0.75 to 0.8 duty cycle to give you head room.

Kind of personal preference though. (I'd hate to see an LS1 engine notched up though... they already operate at 58psi... I'm not sure they could handle much more than 70 without messing with fuel flow or spray patterns).

 

By fudging injector flow #'s you are defeating all the good mathematical algorithms GM put in your ECM/PCM to properly manage fuel delivery. Use the tools provided and try to stay on coarse in order to make tuning easier and fuel delivery more consistant.

Charged Air Systems makes a good regulator which is much better than Aeromotive's.

 

Agreed, and that's precisely my point. To say nothing of the fact that with increased fuel pressure to the injectors your pump will be put under greater strain and will not have the same peak HP fuel flow capability.