Fuel Pressuer

[rightonjoe]

iS THERE A OPTIMAL FUEL PRESSURE

 

[bobc455]

No.

Rough guidelines, depending on application:

Carb- 5.5 PSI
TBI- 15 PSI
NA Port FI- 45 PSI
Boosted FI- 45 PSI + 1 PSI per PSI of boost

 

[rightonjoe]

Bobc455 thanks. I have the FAST system on the way.With this system I will not have to change fuel pressure for tunning . Right now its at 55psi with no vaccumn. I have heard many different pressure setting to use and thought I would try a post and get other veiws thanks

 

[bobc455]

I assume you're running a Turbo 6. Unless you're making other changes right now also (changing turbos or something), I don't think you will have to have to change the fuel pressure, you should be able to tune based on your current FP settings.

Do you run 55 PSI at idle (and all conditions)? That sounds a bit high to me, but maybe other guys can confirm. Nonetheless, the FAST will give you a great idle (and great WOT!!!).

-Bob Cunningham
bobc@gnttype.org

 

[rightonjoe]

Bobc455 I have a 406 SB with a mini ram and 36# injectors

 

[bobc455]

Well I picked up about 1/2 a second when I switched to the Speedpro (predecessor of FAST) compared to my old FI system. I don't know what you were using, but it is possible that you'll be picking up a few ponies. Leave your FP alone for now, but keep an eye on it after you make a 1/4 mile run- if your injector duty cycle (DC%) exceeds 90%, then you might have to do something to increase fuel delivery. That might be to increase fuel pressure, but it might also be that you're running out of fuel pump and it simply can't generate enough pressure at full flow rate (in which case you'll have to replace the pump with a bigger one).

Of course you may want to check with whoever makes your injectors and make sure that 55 PSI isn't going to exceed some sort of design limitation (doubt it, but it's possible). I think that most injectors are designed to run around 45 PSI- is there a reason you're at 55 PSI now?

-Bob Cunningham
bobc@gnttype.org

 

[rightonjoe]

Yes I was not getting enyought fuel and the chip re-grogrammer wasen't helping ( Fastprom)and finally decided to go with the fast / fel pro system