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Old 11-06-2001, 01:49 AM   #14
ImprezaRS dot com
over boosted again
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Member#: 1458
Join Date: May 2000
Chapter/Region: RMIC
Location: Colorado Springs CO USA
Vehicle:
2017 WRX Limited
15 Forester XT, 21 Ascent

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I would highly recommend calling in an expert to help you finish setting up and tuning the car. REALLY!!!!

The Vortech is a rising rate fuel pressure regulator which works in conjunction with the stock FPR. It is hooked up on the fuel return line to block fuel return as boost rises, so the fuel pressure goes up and forces more fuel through the stock injectors. Make sure you have a 5:1 ratio vortech if you are at sea-level (although we use 4:1 up here at 6,000 feet). If you have a 5:1 rise from an approx baseline pressure of 40 psi, then at 8 psi boost you are at about 80 psi fuel pressure. That 80 psi fuel pressure with the stock injectors makes them flow as much as 330cc injectors which is good for about 240hp. That is the limit of your fuel system. With a MY99 and older turbo kit, it is possible to make the injectors exceed 80% duty cycle to support 260-270hp if the injectors go static (not safe).

The S-AFC is not helpful in a 2000+ turbo because the ECU gets nuts when it sees barometric pressure of 35.7 or too high of a MAP voltage, which is about 2-3 psi boost. The best voltage clamp I know of is the Torque Chip which I sell, which clamps the barometric pressure at 32 inches and avoids the "high abs manifold pressure" CE lights and fuel cuts.

Your stock timing advance is still likely to cause detonation as low as 9-10 psi boost with the low compression pistons. This is due to the agressive timing curve of the stock ECU. Do you have a large enough turbo compressor to keep the intake charge air temps cool enough to minimize detonation as boost rises? Do you have an intercooler? Can you run the Sunoco 94 octane or higher?

Don't know why your tach would quit.

Can't help with the external wastegate.

Manual Boost controllers are fine if the car can be tuned for the higher boost levels.

Larry
www.ImprezaRS.com/mymods.htm#turbo
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