ok so what exactly does an FPR do and how does it increase fuel pressure if they are on the return line. i could understand if they are on the supply line but my understanding is that all FPR go on the return line.
i am tryin to figure fuel systems out, so when i install my trubo i have a better understanding.
later
"Z"

Doesn't allow as much fuel to escape through return line and so the fuel gets backed up and injected. This is how I've understood it but there may be a different answer.

yep thats basically it. You will have a high flowing, high pressure fuel pump that will pump fuel into the fuel rail of the engine. At one point in the fuel system, usually close to the fuel rail, there will be a "return" line that takes fuel from the fuel rail back to the fuel tank. This is what the FPR does. Its basically a fuel bleeder valve. Since we have high fuel pressure coming from the pump, when we need high fuel pressure, the FPR will close off more fuel from being sent back to the tank, causeing higher fuel pressure. When we need lower fuel pressure, the FPR will open up more, and allow more fuel to be sent back to the tank, causing lower fuel pressure and flow.

so then if I have a return line coming from a 95 rail, it has a stock FPR attached to it not like 96+ rails, to another FPR, nothin bad will be happen, will I still get the same fuel pressure, than if i cut the stock one off and turn up the pressure on the aftermarket FPR.
get it?
later
"Z"

http://www.2gnt.com/www/corbin/fpr.html

Here's a cutaway of a standard FPR if that helps you visualize things:


Corbin

'95 ESI-T
HRC+FMIC+ETC...



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

sweet now i know what an FPR does, hmm i now how can i use this information to my advantage.:wary
later
"Z"