Fuel pressure at boost

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Jul 5, 2010 | 01:07 AM

matt75

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From: the woodlands tx

Fuel pressure at boost

I have an a&a kit (v3 si-trim) and was wondering at about 10lbs boost, what's an acceptable drop in fuel pressure?

Jul 5, 2010 | 06:19 AM

breecher_7

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From: Your Sister's Bedroom

DROP???????!!!!!!! There should be no drop at all.... Fuel pressure should be boost referenced to INCREASE on a 1:1 ratio.

Jul 6, 2010 | 12:56 PM

BLOWNBLUEZ06

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From: Forney Texas

Quote:

Originally Posted by breecher_7

DROP???????!!!!!!! There should be no drop at all.... Fuel pressure should be boost referenced to INCREASE on a 1:1 ratio.

Only if you're using an aftermarket regulator.

If you just have the stock fuel system, I wouldn't want to see less than 50psi.

Jul 6, 2010 | 02:57 PM

tail_lights

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From: SE TEX

With the stock system I have heard that low 50s is acceptable. Now it can be tuned around if there is a further drop, however it is not recommended.

Jul 6, 2010 | 04:32 PM

zeevette

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From: Pasco WA

Quote:

Originally Posted by BLOWNBLUEZ06

Only if you're using an aftermarket regulator.

If you just have the stock fuel system, I wouldn't want to see less than 50psi.

The system comes with a Lingenfelter FP, so it's not exactly stock.

Jul 6, 2010 | 05:45 PM

BLOWNBLUEZ06

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From: Forney Texas

Quote:

Originally Posted by zeevette

The system comes with a Lingenfelter FP, so it's not exactly stock.

I am really just talking about the fuel pressure regulation side of the system.

I also need to mention that the 50psi cutoff isn't a flat number, meaning if you go up in boost, you decrease your yield and the higher the cutoff point should be. 50psi fuel pressure and 10psi boost yields only 40psi. Change that to 15psi boost and now your yield is only 35psi. That's way unacceptable IMO.

Last edited by BLOWNBLUEZ06; Jul 6, 2010 at 05:47 PM.

Jul 10, 2010 | 09:01 AM

z06sicz

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Quote:

Originally Posted by zeevette

The system comes with a Lingenfelter FP, so it's not exactly stock.

I seen a drop to the low 50's with that pump and the V3 A&A kit injectors. My tuner kept throwing fuel at it, but I think we were at the limits of the pump and or rails. Made 618 to the wheels

Avg AFR was approx 11 from 3-6K and dipped toward 13 from 6-6600.

Jul 24, 2010 | 06:58 AM

rclinton

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Joined: Feb 2006

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From: Jacksonville , NC

Quote:

Originally Posted by z06sicz

I seen a drop to the low 50's with that pump and the V3 A&A kit injectors. My tuner kept throwing fuel at it, but I think we were at the limits of the pump and or rails. Made 618 to the wheels

Avg AFR was approx 11 from 3-6K and dipped toward 13 from 6-6600.

I think the limiting factor at least in my 2002 is the fuel regulator. I saw 57 psi with the stock pump before the A&A install and still see 57 psi solid after the install with LPE pump and larger fuel injectors. Obviously the LPE pump is pushing more GPH but is regulated to 57 psi by the regulator. Im running a V-2 kit though with 6-7 boost.