fuel pressure question with vortech supercharger

97blackgt

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my buddy that goes to college with me has a 99 cobra engine in his 96 gt. He got a good deal on ebay for a vortech supercharger, so he bought it..everything is installed now except it isnt tuned. The problem he has is tat when hes driving and if he pressies in the clutch, the car will stall...bu tthen it starts right back up. When u put a fuel pressure guage on it at idle hes only got 9PSI

my question is what should he be running for FP, at both WOT and at idle?
 

TRUUBLE

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Mine always ran between 35 and 40 . . . up to near 50 at wot
 
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97blackgt

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any ideas why his stumples when the FP is at 20 PSI could that be because its untuned? it runs fine at 9 PSI
 

TRUUBLE

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It's getting enough fuel to idle . . but not to run.

He needs a tune AND a pump.
 
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97blackgt

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hmmm i think ur right...thats kind of what me and my friends were thinking

thanks for the help trubble O0 :drunk:
 
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scarface

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is he on the stock pump ??? fuel is easy. 42lb injectors, 255 pump, AFR. THats all he needs for decent power...


One thing, to know he isnt getting fuel at WOT, that means some has gone to WOT on an UNTUNED blown 4.6.....

It o nly takes a second of detonation to make it go bye bye.
 

Thomas_W

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hes going to need.

Walbro 255LPH HI PRESSURE! fuel pump.. make sure u get this pump for a FI setup.
42# injectors
Adjustable fuel pressure regulator.


at idle w/ vacuum applied i see 38psi. w/o vacuum applied i see 48psi.
 
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97blackgt

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not sue what his fuel pump is but i know for sure he has 42# injectors and AFR

when he turns up fuel pressure hes ok, until he reconnects the caccum line, which the car then stalls within 10 secinds, almost likes its running too rich
 
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scarface

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HE needs a tune. When you buy a SC kit, it comes with a base tune. did he get the chip with the sale?
 

WyoTechMSA

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Idle should be around 35-40, and WOT near 50. If he is still running the stock GT pump that is almost definitely a source of trouble. Also like David said it really needs a tune as well. I drove my buddies Vortech'd 99 around most of this past week and that car was a blast but damn you have to spend alot of money to make that kinda power.
 

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