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Old 05-19-2002, 02:29 AM   #1
Eric SS
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Default What is everyones fuel pressure at idle and what pump/FPR are you using?

I have the Walbro pump, Cartech RRFPR, and stock FPR and my idle pressure is reading 44-49psi on my electric autometer guage. I have my RRFPR screws both turned out all the way and it still rises to about 70psi at 3psi boost. When I was running 9psi, it pegged at WAY past 100psi.

What other setups do people have and how is your WOT and idle fuel pressure. anyoen with cartech/walbro setup having problems keeping your fuelpressure in check? IU'm trying to get a baseline of what good WOT and idle pressures should be. Thanks

Eric
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Old 05-19-2002, 02:37 AM   #2
Andrew
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my car likes to run at around 41-44psi idle. its not the happiest at that for idle becuase sometimes it stalls but during wot it allows a couple more PSI of fuel to get delivered and drastically lowers my EGTs (as compared to 36-38psi).

SX FPR
Walboro Fuel pump
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Old 05-19-2002, 02:38 AM   #3
Eric SS
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One more thing, at that idle pressure (44-49psi) the car idles fine (even with the EJ22T) and when I let it idle for a while and check the plugs, they look fine. No sign of fowling or anything.

Eric
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Old 05-19-2002, 11:51 AM   #4
AaronB
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The stock fuel regulator attached to the fuel rail doesn't allow enough fuel to be returned to the tank, since the hi-flow pump is sending so much more fuel that is unused at idle.

You can swap it out for one from an SVX ($100 new or find one at a junk yard) and it will take the idle pressure back down to 33-35ish.

That is what I did and now I run 34 at idle and about 65 at WOT, just running 6 psi for now.

I think 100psi of fuel is a bit much. I wonder what the stock lines are rated at...
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Old 05-19-2002, 04:55 PM   #5
Graham
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I'm using a Walbro High Pressure pump in my car, a crappy (I think) Vortech RRFPR, and the stock fuel regulator. Right now my car idles at 48-52 psi, depending on how long I drive it. It seems the idle goes lower if I drive it for longer (maybe the pump is getting tired?). I don't really like my idle, as it seems to be too high, though I have not had any problems related to it being a high pressure.

On boost, at full around 4 psi, I see anywhere from 4 BAR to 4.5 BAR of fuel pressure. This converts to 58.8 psi and 66.2 psi. This seems to be fine for on boost fuel, as my EGT's rarely go above 800 C (1472* Farenheit). To be honest, I have no idea which pressure plate I have in my Vortech, as they are not listed on the different plates. I just picked one out of the bag of plates I have and put it in. I think its an 8:1 plate, I don't know.


Graham
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Old 05-19-2002, 05:13 PM   #6
8Complex

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Walbro pump, SVX FPR, running about 32-33psi at idle with the normal rise of 1:1.
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Old 05-19-2002, 09:27 PM   #7
Fitz
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Supra TT fuel pump with stock fuel pressure riser (MY00). Idle pressure is around 48psi and about 50-52 psi under cruise. Under boost it rises one psi for every pound of boost. No idle issues as I'm running the 550cc fuel injectors and Tec-2.

Fitz
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Old 05-19-2002, 09:49 PM   #8
Hojai
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i am running Walbro fuel pump, Sard fuel press. regulator and RC 550cc injectors and TecII. I set the idle fuel press. at 32psi right now but forgot what the fuel press. when it's on boost. I used to have 42psi before i have the Sard regulator installed.
So, what is the normal fuel press. i should get when the car is on boost? let say at 8psi of boost?
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Old 05-20-2002, 01:03 AM   #9
adamsrs
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Im running:
-Stock Legacy Turbo Fuel Pump with unknown miles.
-SARD Type R FPR.
-EJ22t block....
And about 35 psi at idle with NO stock FPR (i removed it) And as you know...my car runs GREAT! (NOT!!!!!)
adamsrs
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Old 05-20-2002, 07:22 AM   #10
wac
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Quote:
No idle issues as I'm running the 550cc fuel injectors and Tec-2.
I beg to differ...

Cold start ran like crap in CO, NM, and TX...

-WaC
Wayne
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Old 05-20-2002, 03:54 PM   #11
Eric SS
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Default

Quote:
Originally posted by adamsrs
Im running:
-Stock Legacy Turbo Fuel Pump with unknown miles.
-SARD Type R FPR.
-EJ22t block....
And about 35 psi at idle with NO stock FPR (i removed it) And as you know...my car runs GREAT! (NOT!!!!!)
adamsrs
So it's OK to remove the stock FPR and run just the RRFPR? I'll try that. THanks

Eric
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Old 05-20-2002, 04:38 PM   #12
8Complex

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NO. You CAN NOT run on just an add-on (Cartech, Bell, Vortech, etc) RRFPR. You need to have a FPR that sets a base pressure for those types of RRFPR's to run off of. You can remove the stock FPR only when you put another FPR in it's place that has the ability to run a base fuel pressure. The add-on regulators just add pressure onto what the existing pressure is in the lines.

Say a FPR is set to run 34psi with the return line back to the tank running 1psi (for example). When you put an add-on RRFPR in line, you set it so that it rises at 1psi at whatever rate. What it in effect does is add pressure between the return of the FPR and the RRFPR. The FPR "adjusts" for the pressure difference by rising the rate in the line going past the injectors into the FPR. The more pressure in the line between the FPR and RRFPR, the higher the pressure in the injector section of line is.
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Old 05-20-2002, 05:26 PM   #13
adamsrs
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But my SARD is fine to run without the stock FPR correct? It is adjustable!
adamsrs
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Old 05-20-2002, 05:46 PM   #14
Eric SS
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OK. And an SVX FPR will bolt right on with no modifications and will work right?

Eric
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Old 05-20-2002, 06:27 PM   #15
wac
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The stock FPR on my 1997 Impreza and on Bill Harvey's 1998 2.5RS also seem to have no pressure issues at idle. We can tune the the RRFPR down to 30 psi at idle, and well past 100 psi under boost if needed. Not sure if these will fit the 2000 fuel rail, though, but I presume that since the SVX one does...

-WaC
Wayne
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Old 05-20-2002, 07:40 PM   #16
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FWIW, the Vortech SMFU is advertised to be able to replace the stock FPR and be a RRFPR as well. I haven't gotten it to work this way yet, but there's no reason you couldn't.

Cheers! John
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Old 05-30-2002, 12:02 AM   #17
b00st3d
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which walbro pump? gss340, gss341, or gss342?

methadon
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Old 05-30-2002, 12:22 AM   #18
david2z4
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anyone have the part number for the SVX one?
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Old 05-30-2002, 01:20 AM   #19
adamsrs
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Dave: My friend Justin (dywstric) is selling a BRAND new one in the Private Classifieds.
adamsrs
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Old 05-30-2002, 01:21 AM   #20
skywalker
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34 PSI at idle under vacuum of course. Running a walbro fuel pump (341 or 342 will work, one of them you have to bend the fuel line a little to fit), 440cc injectors and a Link Plus. I have it tuned pretty well now so that it will start right up like a stock RS and idle just as smooth as a stock RS.
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Old 05-30-2002, 02:32 AM   #21
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one more question to add to this, for any of you running larger injectors....what sizes and do you throw a P0172(Fuel Metering too Rich) code???

jeremy
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