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Old 07-17-2002, 08:49 PM   #1
PunKidd
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Default Fuel pressure and injectors

Ok, I'm running 4.5 pounds on my Ludespeed kit and my injectors are hitting 80% duty cycle when I'm really on it. I would prefer not to go abouve 85% on the injectors and I woul like to run more boost, so my question is do I have to get bigger injectors or can I just get an adjustable FPR and crank up the fuel pressure?
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Old 07-17-2002, 08:56 PM   #2
8Complex

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You could crank up your fuel pressure a bit, but I wouldn't suggest going too high on the stock injectors. What is the current high pressure that you are seeing at full boost?
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Old 07-17-2002, 09:09 PM   #3
PunKidd
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I don't know. I don't have a fuel pressure gauge just yet.
Any idea what a high, but safe pressure is for the stock injectors.
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Old 07-17-2002, 10:52 PM   #4
skywalker
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Get bigger injectors, raising the fuel pressure is not the greatest solution. Since then you will be really overworking the injectors, that were based on lower pressure settings.
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Old 07-18-2002, 03:00 AM   #5
ImprezaRS dot com
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I am told that the stock ECU for 2000-2002 can't handle bigger than 25% over stock on the new injectors if you wanna meet emmisions in closed loop and idle.

I am also told pushing the fuel pressure over 70-75 psi will sometimes make the stock injectors stick open.

Your best bet is to add extra injectors like I did at www.SubaruPlanet.com/sdsefi.htm or to get a programable ECU with bigger injectors if you can afford it.

Otherwise, get a fuel pressure gauge and push about 70-73 psi fuel pressure with a 4:1 or 5:1 RRFPR at 6 psi for 250hp and be happy.
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Old 07-18-2002, 11:53 AM   #6
Graham
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Quote:
Get bigger injectors, raising the fuel pressure is not the greatest solution. Since then you will be really overworking the injectors, that were based on lower pressure settings.

Yah, but there aren't any injectors that are direct replacements for MY 2000/2001 RS's are there? From my knowledge that RC's have to be modified, though Imprezha here on the board is testing out a prototype set for us RS guys, so maybe soon.


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Old 07-18-2002, 12:07 PM   #7
PunKidd
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OK I will avoid running higher pressure beings my main concern was overworking the stock injectors in the first place.
I am already running the Link, so I'll just have to come up w/ the cash to get bigger injectors.
The WRX injectors will work on the EJ25 you just have to add a spacer under the fule rail beings they are taller and you have to chance the o-rings so that they will fit. Andrew at AMR has already been down that road. The same thing goes for the RC injectors, they are not "direct" replacments, but it doesn't take much to make them fit.
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Old 07-18-2002, 12:29 PM   #8
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Quote:
Originally posted by Graham



Yah, but there aren't any injectors that are direct replacements for MY 2000/2001 RS's are there? From my knowledge that RC's have to be modified, though Imprezha here on the board is testing out a prototype set for us RS guys, so maybe soon.


Graham
the DSM injectors will fit in you just need to add some resistors and a few other things to make them work right. shouldn't cost a whole lot more to get them to work.

Brad
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Old 07-19-2002, 01:53 AM   #9
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My rc440cc injectors are not in yet. Tom said it should be in anyday. I'll let you guys know how it works out.

Imprezha
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