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Pressure Drop ?

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Old Nov 3, 2006 | 09:16 PM
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Default Pressure Drop ?

On the dyno my pressure stayed 60psi untill just before redline (6000) rpm then dropped to 40 psi in a blink and stayed at 40 till we let off, then pressure returned right to 60. If the injectors hit 100 d/c would that cause the pressure to drop like this? Should 42 lbs SVO and a255 LPH pump not run out at 425hp at 6psi ?
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Old Nov 3, 2006 | 10:58 PM
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No, you ran out of pump.
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Old Nov 4, 2006 | 05:55 AM
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I had a single pump in the tank of my Z28 at 540 rwhp, which was extemely borderline, but it worked. You certainly have a fuel related problem, and I would look at the pump and make sure you have a new fuel filter. Bob
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Old Nov 5, 2006 | 11:42 AM
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when I did the Racetronix pump I put on a new Autozone fuel filter cause the car had 38,000 miles on it. I thought that a new AC Delco fuel filter would be the cheapest guess at a solution. Since then I've done a few WOT runs in 3rd and 4th gear and have not seen a pressure drop, but I never did any runs on the street with my pressure guage before changing the filter. Could it have been as simple as a cheap fuel filter? The dynopak dyno puts a real load on the car, could it be more load than a 4th gear run to redline on the street? (i mean highway)
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Old Nov 5, 2006 | 06:58 PM
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Originally Posted by 2002ws-6
when I did the Racetronix pump I put on a new Autozone fuel filter cause the car had 38,000 miles on it. I thought that a new AC Delco fuel filter would be the cheapest guess at a solution. Since then I've done a few WOT runs in 3rd and 4th gear and have not seen a pressure drop, but I never did any runs on the street with my pressure guage before changing the filter. Could it have been as simple as a cheap fuel filter? The dynopak dyno puts a real load on the car, could it be more load than a 4th gear run to redline on the street? (i mean highway)
The Dyno should simulate actual road conditions, so I don't think the dyno was a problem. I'd say it was the filter since all is well now. Bob
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