Fuel Pressure Tech. Question

[Kisorperformance]

OK, I know i need an adjustable FPR..... it runs about 43psi on vacume and 50 off...... and i'm getting one here after christmas but since i first got this engine, oh yeah its an RB20DET, when looking at the fuel system this thing runs, i can't figure out what the other "regulator" on the firewall end of the fuel rail does.

while looking at pictures in the "show your RB engine pics" thread i'm noticing that only some of the RB's have this device on the feed side before the rail.

my fuel comes in at the front, goes into a hard line back under the upper intake, into a rubber hose and then to this regulator-like valve on the rear of the fuel rail. the actual regulator is on the front of the rail like normal engines are setup....... the vacume line from this thing at the back goes to a tee on the IAC piping.

anyone know it's function? does this restrict anything when boost surge is different between the piping and intake??

main thing i'm concerned about is when i get my adj. fpr and start doing upgrades, is this thing gonna kcuf me... is it removable? do i need to look at a different fuel rail? or just ignore it.....

i'll try to get pics up tommorrow but it's snowing like tihs out

Thanks'Brad

[Joe]

its a damper to absorb pulses in the fuel delivery

not needed.

[Kisorperformance]

ok it appears to have an o-ring style fitting and it bolts on.... best scenerio for removal??

[Joe]

run a new rubber line from the hardline return under the intake to the hardline on your chassis.

[Kisorperformance]

did you read my previous post?

it bolts onto the rail.... can't just run a hose..... it's not on the return side......

[DriftingisLame]

I'm curious as to why this is as well. I have 2 rb20's, one had what looked to be a fuel pressure regulator on the front and rear. My new RB20 has a fuel pressure regulator (nismo), on the front, and then a hardline coming off the back of the fuel rail, going back to the tank ( I think).

Not sure which one I should use.

[Bwana]

First of all, the line that comes out of the FPR is ALWAYS the return line to the tank.

The regulator regulates the fuel pressure by adjusting how much it releases from the rail, not how much it allows in.

Just wanted to clarify...

[Kisorperformance]

not sure if that was an answer for me or not but, correct.....

it looks like this thing would reduce pressure if there were boost in the intercooler side and the throttle plate were closed. the line from the top of it goes to a tee on the iac / thermal valve tubing...... i just can't see what benefit it had for operation.... i found a retrofit assy. for removing the fpr and using an external style, i think they refered to a type 2 nismo fpr...... anyway as long as i don't see any restriction from this device i'm not going to worry about it....

thanks for the info guy's

Brad