LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Fuel pressure

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Old 07-21-2006, 02:07 AM
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JUICED96Z
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Default Fuel pressure

Anyone know what the optimal (best performance) fuel pressure is for an LT1 with bolt ons, tune, good ignition, Racetronix fuel pump, gears?

Been thinking my stock regulator has been a tad bad for a while now. Throws a rich code with a new pump, filter, and clean injectors. Picked up an Aeromotive peice for $95.

I know they say if you are no on a dyno to do a "seat of your pants test" but I am just trying to figure out what I sould shoot for with it being a tuned bolt on car. Going to spray it in the near future also, 150 shot.
Old 07-21-2006, 02:30 AM
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I would say set it for around 42-46# and then test it and see how it feels and runs...
Old 07-21-2006, 06:28 AM
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Set it for STOCK pressure do not use an adjustable regulator as a tuning tool use it as a part of the fuel system. If you vary it from the 43.5 or so psi the tuner was figuring on you will just throw off the whole tune. Try and "tune" for power and combine with the tune you run a serious risk of going lean on the bottle.

It can not be said enougn times.

THE REGULATOR IS A FUEL SYSTEM PART NOT A TUNING TOOL! Use the regulator to control fuel sypply and the computer to decide what to do with that fuel.
Old 07-21-2006, 01:02 PM
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Originally Posted by 96capricemgr
Set it for STOCK pressure do not use an adjustable regulator as a tuning tool use it as a part of the fuel system. If you vary it from the 43.5 or so psi the tuner was figuring on you will just throw off the whole tune. Try and "tune" for power and combine with the tune you run a serious risk of going lean on the bottle.

It can not be said enougn times.

THE REGULATOR IS A FUEL SYSTEM PART NOT A TUNING TOOL! Use the regulator to control fuel sypply and the computer to decide what to do with that fuel.
Hence the reason for not wanting to set it low. Might e-mail Ion and see what he says since he tuned it. I was going to put it on the low side untill I got my H/C so the car and it will need a new tune then regardless.
Old 07-21-2006, 05:53 PM
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Originally Posted by 96capricemgr
Set it for STOCK pressure do not use an adjustable regulator as a tuning tool use it as a part of the fuel system. If you vary it from the 43.5 or so psi the tuner was figuring on you will just throw off the whole tune. Try and "tune" for power and combine with the tune you run a serious risk of going lean on the bottle.

It can not be said enougn times.

THE REGULATOR IS A FUEL SYSTEM PART NOT A TUNING TOOL! Use the regulator to control fuel sypply and the computer to decide what to do with that fuel.


Correct. There is no real good reason to change pressure unless your trying to slightly cheat volume for a slightly lower injector output then you need. Otherwise, pressure should remain the same as stock.
Old 07-21-2006, 10:00 PM
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Whats a good fuel pressure for my set up?

100-150 shot Wet kit
Old 07-21-2006, 10:02 PM
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Originally Posted by edlt1
Whats a good fuel pressure for my set up?

100-150 shot Wet kit

STOCK unless the pcm was tuned for something else and then that pressure should be used.
Old 07-21-2006, 11:03 PM
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Pressure depends on the tune as much as any thing else. We run some cars at 50Psi for better idle patterns
Old 07-22-2006, 09:44 PM
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Originally Posted by TwoFast4Lv
Pressure depends on the tune as much as any thing else. We run some cars at 50Psi for better idle patterns
Yes but you understand what you are doing.
Wouldn't you agree that most folks trying to "tune" with one will do more harm than good?
Old 07-22-2006, 10:04 PM
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Originally Posted by 96capricemgr
Yes but you understand what you are doing.
Wouldn't you agree that most folks trying to "tune" with one will do more harm than good?

I can't speak for everyone else Just us
Old 07-22-2006, 11:49 PM
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you really want to blow someones mind? Try to explain to them that lowering stock fuel pressure on a stock tune will actually net them a HP gain. I'll bet you get the typical "Oh Noes!!, thats unpossible. You need to raise the pressure yo".
Old 07-23-2006, 08:56 AM
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It can get yopu a temporary power gain but once the pcm learns the part throttle fuel trims and is adding fuel it will do so at WOT as well making an already rich factory tune run worse. So again I say a AFPR is not a tuning tool but a part of the fuel system. They do have uses but if you have to ask generally you are not yet experianced enough to competently use one.

You can however use them like Ellis said, or to make marginally sized injectors flow more, have heard higher system pressure can help if you spray A LOT and are having pressure drop at activation problems ETC. but every one of these circumstances requires you to change other things with the pressure changes, and you still have to go into the pcm to get fueling right across the board.




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