FPR Setup???

[chriso]

I just finished installing my new Walbro fuel pump and AFPR in my car. I set the regulator up using the bypass jumpers in the diag box (B+ and Fp) at 38psi. Next I started the car and double checked it with the vacuum line disconnected and plugged. As soon as I connect the vacuum line the pressure drops to around 28psi. I thought the regulator should maintain the pressure at 38 which is where I originally set it. Is this correct? Oh, and btw I still have the stock 440's in place.

I'm just a little concerned since I don't have electronics installed yet to monitor the AFR (the only thing I have right now is an autometer AFR gauge) and don't want to lean out my engine.

 

[dbsupra90]

yes that is correct. when you connect the vac line it should drop 8-10 psi.

 

[chriso]

I checked my TSRM and it says that normal pressure for a stock turbo is 23-30 psi at idle so I guess I'm alright. I just thought it should be higher. Next weekend when I switch in my 550's I wonder if the pressure should be the same or higher?

 

[shaeff]

generally, you'd want a little LOWER pressure with the 550's. check your vf while you're doing all this. (if you raise the fuel pressure with larger injectors, you'll run more rich than you are now)

-shaeff

 

[chriso]

generally, you'd want a little LOWER pressure with the 550's. check your vf while you're doing all this. (if you raise the fuel pressure with larger injectors, you'll run more rich than you are now)

-shaeff

vf ?????

What are you guys running with the 550's and LexAFM's ???

 

[isnms]

 

[shaeff]

vf ?????

What are you guys running with the 550's and LexAFM's ???

lex afm, 550's, walbro 255, aeromotive afpr, and no pulsation dampenr. (though, you could leave it on)

i also have all new fuel lines, except for the super-huge one that runs under the car.

here's another informative link about vf:
http://www.supras.com/06/techcenter/display.php?QID=80

-shaeff

 

[theDon]

shaeff what base FP are you running with or without vac? I have exact same setup and was also noticing stock specs are too rich

 

[chriso]

Good information, thanks shaef !!! +1

 

[shaeff]

you're welcome, chris.

bcg04- i wouldn't recommend using anyone else's numbers for your own setup, but mine are incredibly low even with the vacuum off. mid to low 20's i believe. i can check once i get my heater core back from the shop, and hook it back up. (otherwise it's a coolant shower for my car, and that's not fun.)

-shaeff

 

[theDon]

Thx shaeff, you are right I wouldn't use the numbers but I'd appreciate knowing the ball park you are in. The consensus including what you said above seems to be to use lower FP than stock specs - that alone helps.

So you set your base FP with the vf signal? Is using the vf signal related at all to using a wideband? Thinking vf is what the car "thinks" it is and wideband is actually what it is?

 

[isnms]

VF is derived from the o2 sensor
this is a good read - http://alflash.narod.ru/vf1.htm

 

[shaeff]

and there it is^ i'd rep you again for good info, but i gotta spread the lovin' a bit.

-shaeff

 

[isnms]

Thanks, I appreciate it :biglaugh: