LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

fuel pressure on stock lt1

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Old 01-04-2005, 10:26 PM
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fuel pressure on stock lt1

what is the best fuel psi on a bolt on lt1? i've seen things on how stock is best, and others who have lowered the psi to like 36 and got 13rwhp out of it. need some more info. thanx???
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Old 01-05-2005, 10:51 AM
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Re: fuel pressure on stock lt1

The important number is the A/F. I believe that you might experience a litttle leaner condition (factory is quite rich) when you first reduce the FP; but the OBD11 system compensates for the leaner condition by reducing the injector pulse time. Net result: you are back where you started.

Probably best to leave the FP alone and have your PCM programmed for a leaner mixfture. jmho
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Old 01-06-2005, 12:16 AM
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Re: fuel pressure on stock lt1

Originally Posted by BUBBA
The important number is the A/F. I believe that you might experience a litttle leaner condition (factory is quite rich) when you first reduce the FP; but the OBD11 system compensates for the leaner condition by reducing the injector pulse time. Net result: you are back where you started.

Probably best to leave the FP alone and have your PCM programmed for a leaner mixfture. jmho
Both OBD-I (94/95) and OBD-II (96/97) systems will compensate for the reduced fuel pressure. The pulse widths are INCREASED to make up for the reduced fuel flow through the injectors/lean condition.

Leave the pressure stock, and have the PCM's power enrichment (PE) mode target A/F ratios reprogrammed leaner by one of the mail order tuners..... guaranteed 15HP power increase.
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Old 01-06-2005, 09:32 AM
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Re: fuel pressure on stock lt1

Yah, increased, that's what I meant to say.
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