what psi do you set your fuel pressure to?

[bdazzgt]

i just put an adjustable fuel pressure regulator on the stang, the paper said stock psi was 44 so i set mine to 48 is this too much pressure? the car seems to run better and idles a whole lot better.i just want to make sure im not going to run pig rich and stuff? thanks guys

 

[Rick 91GT]

36-40 with vac off is normal....48 is way to high

 

[90stang5speed]

I think stock is 39 or 40 psi but, if you dont have a way to tune, the EEC is going to pick up that you are running rich and adjust fuel trims to bring you back to where the tune wants to be. I think it has a window of +- 15% and once you exceed that, you will get a CEL saying you have reached the lean/rich limit. I have a TWEECER Rt & when I hit 95+% injector duty cycle at WOT with my old 19 lb injectors, I cranked up the pressure to 65 psi & told the EEC that I had 24 Lbs injectors. It ran pretty much the same but, because I told the EEC the injectors were bigger, my duty cycle dropped to around 70% at WOT. I guess what I was trying to say is, in my opinion, Yes, you can run a lot more pressure but, if you cant really tune for it, you are just working the pump harder & not getting much of a gain. Im no expert at this stuff so, what worked for me might not be what someone else with more experience would tell ya. My pressure is now set at 40 psi with 42 lb injectors. the 65 psi was a bandaid until I could afford to upgrade.

 

[bdazzgt]

rick is that normal for a modified car?

 

[NIKwoaC]

What are the modifications to the car? Raising the fuel pressure is usually unnecessary.

 

[Rick 91GT]

Whats the exact combo? If thw injectors are properly sized then 36-40 usually is normal, bumping the pressure higher is a bandaid if you need the fuel up top and have too small of an injector.

 

[bdazzgt]

it has trickflow twisted wedge heads, street heat intake, comp 270xe cam, 10:1 compression,24lb injectors, 76mm mass air meter, 190lph fuel pump, 1.6 roller rockers. the reason i replace it is because i thought my old one was bad initially and the car could just just a bit more fuel at idle,
update: i got up this morning to lower the fuel pressure at 36 it seemed like it idled just a bit rough, i moved it to 38 and it runs like a new car, this also fixed my random dying at stoplights and surging idle. i think all is well now to get my starter problem fixed....