What are u guys setting your fuel pressure at NA? I was told to set it at 58-60psi. Stock was 53 psi and vac referenced to 60 psi correct?

I was told to not run vacuum ref on na setup. But I done some reading tonight and it said adjust psi to your WOT A/F ratio. And let ECM relearn the drivability part. Is this correct?

 

No, you want to remove the vac source, set it to 58 psi. Then reattach the vac hose. Fuel pressure will then drop to about 45 depending how much vac you see. And go to 58 when at wot

 

Ok that helps. I thought u only used the vac source for boost only?

 

No, it is important to use a vac source regulator on all setups. When the engine is seeing vacuum, it literally sucks the fuel out of the injector. That is why it lowers the pressure at the rails to keep fuel flow linear. Just the opposite in boost. Boost pushes on the injector so the fuel pressure is raised at a 1:1 ratio to get the fuel injected properly into the runner.

 

ok ill hook it up today. Thanks guys!

 

Hooked it up and idle psi was around 53. Now its Running rich at WOT around 11 somethin A/F ratio. Gonna try resetting computer and try again.

 

Should be pulling more vacuum than that. How did you set the pressure?

 

i have a aermomotive pressure gauge before one of the rails. It shows 53psi at idle and drops to around 45ish at around 2000rpm. Jumps to 58psi at WOT. I think its working. Only thing is the rich WOT a/f ratio. I think it was around 11.8 today. Was around 13.1 without vaccum. Should i just back the WOT pressure down some at regulator?

 

Do you have a tune? What else under the hood is not stock besides the fuel pressure regulator?

 

i have a tbss intake with fast billet rails installed on it. -6 an feed and return with 255 walbro. I run a Nelson Tune currently.