is this true fuel regulator myth

Texstang9682

New Member

Oct 8, 2006

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Austin, Texas

Dec 17, 2006

#1

• Dec 17, 2006

• #1

I heard from a friend that if you buy an adjustable fuel regulator that you can acually get 21#'s out of the stock 19# injectors. True or BS? Also what is the point of an AFPR for and NA car, will it help you gain power? It seems like a decently cheap mod. Or are they just for forced induction? Just curious.

 

SaleenGT2001

Well-Known Member

Jul 18, 2005

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Four Oaks NC

Dec 17, 2006

#2

• Dec 17, 2006

• #2

why do you need more fuel?

 

S

Saleen4971

New Member

Mar 26, 2003

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Setauket, LI

Dec 17, 2006

#3

• Dec 17, 2006

• #3

you can. the 19# is rated at a certian pressure (probly 39psi fuel pressure). my jeep runs at 49psi - so for instance, FMS 24's woudl run aroudn 27#. there is a formula to it.

since injecotrs are obviously only of EFI cars w/ O2 sensors, it wont do anything. itll run rich at first, then the PCM will lean it back out to stoich

 

Texstang9682

New Member

Oct 8, 2006

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Austin, Texas

Dec 17, 2006

#4

• Dec 17, 2006

• #4

SaleenGT2001 said:

why do you need more fuel?

Click to expand...

I dont really need more fuel, I was just wanting to know if its true. And what the point of the AFPR is for.

 

Stan Weiss

Member

Dec 8, 2006

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Philadelphia, PA

Dec 17, 2006

#5

• Dec 17, 2006

• #5

Yes it is true. I have a calculator on my web site which will let you see the change in flow as you change fuel pressure..http://users.erols.com/srweiss/index.html#jcalc

 

M

MatthewP

Founding Member

Dec 7, 2001

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Calgary, Alberta

Dec 17, 2006

#6

• Dec 17, 2006

• #6

You can make small Air/Fuel ratio changes with an adjustable fuel pressure regulator which may help you to optimize the car on a dyno without an electronic calibration. At WOT, the O2 sensors are ignored, so the AFR change introduced by a change in fuel pressure will not be "learned away" by the adaptive control system at WOT.

In most cases, the stock fuel pressure will work just fine.

BTW: If you run a late model returnless fuel system, it uses an electronic pressure transducer, not a regulator, and it works a little differently.

-Matthew

 

T

thomas91169

I'd donkey punch my sister.

Aug 19, 2005

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0

Modesto, CA

Dec 17, 2006

#7

• Dec 17, 2006

• #7

yes. its because the fuel rail will hold a higher pressure, so when the injector opens, more fuel will be pushed through at the same injector pulsewidth. back in the days where efi tuning was hit and miss, upping the fuel pressure was the number one way to tune. now that you can slap in a new set of readily available injectors and tune it within minutes, its not used as much.

 

triggz

Founding Member

May 15, 2002

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Gadsden, AL

Dec 17, 2006

#8

• Dec 17, 2006

• #8

If you're NA, there is no gain to be had by increasing your fuel pressure. I dont think any of the 4.6L mustangs even have fuel pressure regulators (96-98 may, I cant recall for sure).

 

Mike97gt

it doe snot

Founding Member

Jan 26, 1999

10,633

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the people's republic of massachusetts

Dec 17, 2006

#9

• Dec 17, 2006

• #9

MatthewP said:

You can make small Air/Fuel ratio changes with an adjustable fuel pressure regulator which may help you to optimize the car on a dyno without an electronic calibration. At WOT, the O2 sensors are ignored, so the AFR change introduced by a change in fuel pressure will not be "learned away" by the adaptive control system at WOT.

In most cases, the stock fuel pressure will work just fine.

BTW: If you run a late model returnless fuel system, it uses an electronic pressure transducer, not a regulator, and it works a little differently.

-Matthew

Click to expand...

EEC V adaptive strategy modifies OL and wide open throttle from CL readings over time, you will be able to make small adjustments with a fuel presure reg. but after you drive it for a little while it will unlearn it even at WOT.