Need help with FPR setting...
Thread Starter
Mike
Joined: Jun 2010
Posts: 65
Likes: 0
From: Loganville, Ga
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!
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!
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
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:
At idle, the fuel pressure should be about 28.4 psi. When the FPR is vented to the atmosphere, the fuel pressure should be between 34.1 and 34.9 psi. With engine off, ignition key to the on position, and yellow connector jumped, the fuel pressure should be between 64.0 and 85.3 psi.
talking head
Joined: Apr 2008
Posts: 2,775
Likes: 15
From: Perth, WA, OZ
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 )
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 )
Thread Starter
Mike
Joined: Jun 2010
Posts: 65
Likes: 0
From: Loganville, Ga
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
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
Ok thanks for the info! I really appreciate your help!
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
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Thread Starter
Mike
Joined: Jun 2010
Posts: 65
Likes: 0
From: Loganville, Ga
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
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
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