Fuel Pressure / Speed Density
 

Hey all,

I just pulled off my Holley FPR last night, because I couldn't get my car to run like it did with the stock FPR. The stocker reads 31 at idle, and 40 at WOT. (no vac) I tried everything from 30 / 39 to 38 / 47 on the Holley and the car just wouldn't run like it did before. (and now)

What would you recommend for fuel pressure & timing with the following mods?

'98 Explorer SB
GT40P heads (shaved)
Cobra upper
Ported Cobra lower
Cobra roller 1.7's
Stock SSV cam
Pullies
Flows
CAI

Car ran 13.11 @ 106 with my old, chipped up Pirelli P600's, with 1.9 60's.

It'll be well into the 12's with the new Nitto 555 drag radials that were slipped on the pony's last night.

What do I stand to gain if I can get it tuned with the adj FPR?

Thanks in advance...

I would start at about 41psi and 16 degrees of initial timing.

Every car is different but thats where my car likes it.

Oops- I forgot and you reminded me.

I was also at 16* initial timing, and tried 14 and 15* also.

The car just didn't seem to have what it did before. Last night, I wento out with the Nitto's (since I had to try them) and with the Holley, at 44 / 37 I could chirp 2nd powershifting. With the stocker back on, they lit up for about 18." I guess I had too much fuel going to it.

I'm taking it to the track tonight with the tools to swap the regulator, and I'll try both, just to see.

Thanks, Dark- I'll try your readings and see how it works. How much difference in performance did you get from stock to 41 psi?

I honestly couldnt tell you how much difference I got from changing fuel pressure other than If I bump it up to 45psi I get a better mph and a worse ET:confused:

stock fuwel pressure is 39 psi. do you have any mods besides the regulator. i would leave around 42-45 psi if not, but it all depends.

Put the stock one on and leave it alone.

Thanks, Workcar. That's what I did last night.

I was waiting for your post... :D

Thanks again, all.

No matter what I do my works best at 38-39psi.