i have 30# injectors and cant lower fuel pressure below 20ish.... im planning on putting in 400cc soon, but im concerned i wont be able to get it to idle right.... i have a stock 95 return line and sfmu... i was wondering how many people have gotten the 95 system pressure lower than 20... i just want to see if i should install a larger return line or if i have a problem somewhere else...thanks
doug

its more likely he SFMU limiting you, not the return line.

20psi idle on 30# injectors is pretty low, fuel mixture wise.

And actually, I'd be more worried about the atomization at that pressure, rather than the SFMU or return line restrictions. My car would sputter and die under ~18psi idle on my Ford 42lb'rs (and RC 440's).

I have ford/bosch 440's and it idles fine, even at 12psi. Sometimes I see 12psi, usually between 15-18. You'll probably idle fine at 20psi, but I'd be willing to bet you will be able to get lower pressures when you install the 400s.

I can lower my fuel pressure to 10 psi (and the car idle fine) on my stock 95 lines w/ sfmu. Did you change the inlet fitting to the sfmu? did you shave off the taper on it if you did?

no, ive never heard of shaving it off? im not sure what youre talking about either... so the stock return line is fine, its got to be something before that limiting me correct?...thanks
doug

injectors? i believe bigger injectors dump more of the pressure.

Originally posted by lickscissors
no, ive never heard of shaving it off? im not sure what youre talking about either... so the stock return line is fine, its got to be something before that limiting me correct?...thanks doug

If you didn't change the inlet fitting don't worry about it. If you ever take it off you'll see what am talking about. They seal using a o-ring, not the AN flare (which would restrict flow in it's design).

Originally posted by sike
injectors? i believe bigger injectors dump more of the pressure.

Originally posted by WickedESi
If you didn't change the inlet fitting don't worry about it. If you ever take it off you'll see what am talking about. They seal using a o-ring, not the AN flare (which would restrict flow in it's design).

That's interesting... I did replace my inlet fitting (sfmu from ebay) and I'm not sure if it was o-ringed or flared now that I think about it. So that may be why i was limited to 18psi minimum at idle.

It might just be the spring and disk combination you have chosen that is limiting your minimum fuel pressure. When messing around with different disks and springs, I noticed that I was limited on my max and min idle fuel pressures depending on what combination I chose.

Corbin

'95 ESI-T
Now with more power and fewer leaks



Gimme fuel...Gimme fire...Gimme that which I desire

Originally posted by thedawg

Originally posted by WickedESi If you didn't change the inlet fitting don't worry about it. If you ever take it off you'll see what am talking about. They seal using a o-ring, not the AN flare (which would restrict flow in it's design).

That's interesting... I did replace my inlet fitting (sfmu from ebay) and I'm not sure if it was o-ringed or flared now that I think about it. So that may be why i was limited to 18psi minimum at idle.

For further detail, the fitting that comes with the sfmu is a -6 male FLARED fitting, with the flare CUT OFF. It seals using a nitrile oring placed over the fitting. It is a definate restriction if you don't cut the flare off before screwing it into the SFMU.

I thought they were just -6 to 1/4" NPT straight thread fittings with an O-ring.

Originally posted by WickedESi

Originally posted by thedawg

Originally posted by WickedESi If you didn't change the inlet fitting don't worry about it. If you ever take it off you'll see what am talking about. They seal using a o-ring, not the AN flare (which would restrict flow in it's design).

That's interesting... I did replace my inlet fitting (sfmu from ebay) and I'm not sure if it was o-ringed or flared now that I think about it. So that may be why i was limited to 18psi minimum at idle.

For further detail, the fitting that comes with the sfmu is a -6 male FLARED fitting, with the flare CUT OFF. It seals using a nitrile oring placed over the fitting. It is a definate restriction if you don't cut the flare off before screwing it into the SFMU.

Clarification:
It could only be a restriction on the return line.
Its a -6AN port fitting. Thats what I use. With the rubber o-ring.