Just curious. I bumped my preassure to about 50 psi vacuum disconnected and the car really responded quite well to it. Its pulling real strong. I knoe TPI is rich from the factory. Is this to much and am I gonna screw the pump. But the car eally likes it. And so do I

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1987 T/A GTA 5.7L, Bored .020 and ported for .202 valves, edelbrock headers, flowmaster exhaust, JET STAGE II chip, Comp CAM, Adjustable fuel pressure, Airfoil, K&N filter, B&M stage 2 shift kit, and a home depot ram air(Hey it looks good and it works)

 

50 with the line off and blocked should be giving you upper 30s to low 40s with it on.

Pressure drops about 1 psi for each 2 inches of vacuum the engine pulls.

Factory pressures changed over the years, with GM raising the pressure as new model years hit the showroom.

Unless you spend a lot of time at WOT, hence low vacuum and high fuel pressure, your pump won't be working that hard. I don't believe your setting will have any detrimental effect on pump life.

Now that big Oak tree directly in front of you as you blast down the roadway, well that's another story altogether. They've been known to dramatically shorten all kinds of 'life'.

Jake

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1986 Corvette Coupe, 415 CID, Edelbrock 6073s, ZZ9

 

i think stock is about 46 PSI, with 50 being a good HIGH setting.

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- David
88' GTA 5.7L TPI MODS---> air foil, K&N, Shift Kit, 180* therm, TB bypass, Gutted CAT, Flowmaster 80 Series

 

Mine Was 44.5 on a stock 90 IROC 350. I bumped mine up from stock to around 48. I thought it ran better but when I dropped it back I found what I had lost. The stock chips are on the rich side.

You should really try some timed runs to see what is best.



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90 IROC
SuperRamed 406
Trickflow 23* heads

 

Rail pressure should be 37PSIG +/- 3PSIG at idle with vacuum connected, 44PSIG +/- 3PSIG with no vacuum.

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Later,
Vader
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"Click - Click - BOOM!"
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