What's your Fuel Pressure set to?

[desant78]

I see so many people have these fancy AFPR, but I was wondering if anyone sets them higher than 37-38psi at atmposhere? I have a e3 16g with a keydriver stg3 chip and 560's runinng 18-20 psi. Im at stock levels and don't like how high my AFR's are. I gave my exhaust to a local shop to tidy up, but they didn't do such a great job.

Bottom line, I have a small leak inbetween my o2 housing and downpipe. Which is after my stock 02 sensor but before my AEM wideband. I read nothing at idle, but at WOT I see brifely 11.9 then it climbs to 13. Mostly sits at 12.8ish and slowly floats up. I figured at WOT, that there would be enough exhaust present to give an accurate reading, and at idle just not enough flow to full immerse the sensor in exhaust gas.

Anyway at night I keep thinking since I added boost, and have small injectors, I should add a bit of fuel. Might be a band-aid covering a real problem.

Opinions, suggestions, etc are appreciated it.

thanks in advance!

 

[nemovr4]

I am and have been running mine at 46...so far so good, but it is supposed to be temporary because I have some other problems I can't fix right now. I would leave it right around 37-38 though.

As you said though I am using it as a band-aid...

 

[DynastyLCD]

Sal! i've got a simliar setup in my GVR4 now, except a 14b right now.

in my 1g, i tuned it for low 11 AFR's. with the Evo 3 16g, Evo 8 injectors and Evo 8 MAF, it was an awesome combo. it ran like a raped ape - but with a 3" exhaust, the boost would creep up to 27 almost every time. i set my boost to 21-22 psi, which helped with the creep a little. i also upped my AFPR from the 37-38 mark to either 42 or 43. i get perfect low 11 AFR's through the rev range, and even when it creeps up to 27, it might goto 11.6 or 11.8 at most.

try it, buddy! it will help you out!

 

[mikus]

Lots of AFPR's out there leaking air @ adjusting screw, lots of inaccurate fuel pressure gauges.

I did raise FP slightly on my last car but it's a baseline adjustment, not a final tuning bit.

 

[kama1]

Ran 43 with a bosch reg,560cc,wally 255 and evo 3 16g at 18psi.

 

[prove_it]

I'm using 43psi since my FIC 850's are tested at that. Better off running the pressure that matches the rated test of your injectors. At 37psi my 850's won't flow 850, it's less.

That's always my recommendation. Run the FP same as the injector test rating. Remember as you add boost, fuel pressure rises 1:1.

I would look into why your showing so lean. You didn't mention what wideband your using. My LC-1 gets a little inaccurate after 6k miles, once I do a free air calibration it shows spot on to the tune.

Correct me if I'm wrong, but in a low back pressure exhaust won't a small leak actually pull air in due to high gas velocity? Which would then read a lean condition even though it's rich?

 

[desant78]

Quoting DynastyLCD:
Sal! i've got a simliar setup in my GVR4 now, except a 14b right now.

in my 1g, i tuned it for low 11 AFR's. with the Evo 3 16g, Evo 8 injectors and Evo 8 MAF, it was an awesome combo. it ran like a raped ape - but with a 3" exhaust, the boost would creep up to 27 almost every time. i set my boost to 21-22 psi, which helped with the creep a little. i also upped my AFPR from the 37-38 mark to either 42 or 43. i get perfect low 11 AFR's through the rev range, and even when it creeps up to 27, it might goto 11.6 or 11.8 at most.

try it, buddy! it will help you out!



after yesterday of testing at work (here we have a small runway used back in WWII) I settled with 42ish. I've got the same set up as you phil! evo8 inj and evo8 maf. Now when the boost comes in, the car lunges forward in a way more aggressive manner. Also, I almost hit my rev limit a few times, so it's def reving faster.

thanks for the input everyone! Im going to check my plugs by the weekend to verify I'm not running to rich.