Need help with FPR setting...
 

Ill start with my setup...I am currently running 720 injectors (primary/secondary) with a Walbro 255 fuel pump and adjustable fuel pressure reg. The motor is extended street ported with a stock turbo on 12-15 psi of boost exhaust etc.

My question is what to set my fuel pressure at? And I read something about having to disconnect the vac when I set it so what PSI should it read with the vac disconnected and what PSI should I see when its connected. Thanks for the help in advance!

bump...can some please lend a hand? thanks...

so out of 100+ members to view this no one can give me the PSI? lol ok thanks anyway guys...

What was it at previously? If you set it different than what the car was previously tuned on, you'll see richer/leaner AFRs across the board.

If this is the first tune, you have some wiggle room here so it's hard to give an exact answer. Stock FC pressure at idle is ~30psi as I recall. Fuel injector flow ratings are generally given at 43.5psi.

EDIT:
http://mazdarx7.iougs.com/fuel.shtml

universal standard is to start at 43.5 psi ( 3 bar ) with no vacuum applied to the reg

depending on the porting and idle speed , the vacuum will change and thus can sometimes be almost 10 psi ( 20 inches Hg ) less during idle ( with vac on the reg )

This is my first tune. Im running a Rtek 1.8 (standalone). Im really not positive what it i set to now because the previous owner was the one that set it. I was wanting to know what to set it at now since im pulling my FD FP out and putting in a Walbro 255 (using the same 720cc injectors). Also wondering if the pump would make a significant difference in pressure and if it would even need to be adjusted after the change...? Thank you very much for your reply by the way!

Ok thanks for the info! I really appreciate your help!

Shouldn't unless you're putting in a pump that will flow more fuel than your return lines can handle (you're not). You should check it and set it anyways.

Also check out this link. You can skip all of the stuff that is Megasquirt related, but there is good general EFI related information in there.
http://www.msextra.com/doc/ms3/fuel.html

Thanks for that link!! alot of info on there! Im putting the 255 to ensure efficiency as well as support up coming mods (bigger turbo etc.)...