What should my fuel pressure be?
Thread Starter
Burning Brakes
Joined: Sep 2005
Posts: 1,078
Likes: 0
From: Santee CA
What should my fuel pressure be?
This is probably one of those subjective questions again, but...
In doing our engine rebuild, one of the things that has come up is whether or not we should purchase a new fuel pump for the car. We're getting a fuel pressure gauge that will be connected in line in the engine bay, but the question that we're not sure of is, What's an acceptable fuel pressure at idle, and what's not? When do we need to have a higher lph/gph fuel pump than stock?
In doing our engine rebuild, one of the things that has come up is whether or not we should purchase a new fuel pump for the car. We're getting a fuel pressure gauge that will be connected in line in the engine bay, but the question that we're not sure of is, What's an acceptable fuel pressure at idle, and what's not? When do we need to have a higher lph/gph fuel pump than stock?
Instructor
Joined: Sep 2005
Posts: 241
Likes: 0
From: St Louis Missouri
If you have the Q-jet I think the pressure is supposed to be around 6psi. If you have an aftermarket carb check the carb documentation. I think that mechanical fuel pumps have their highest pressure output at idle, but I don’t remember. As far as how many gph, get all that you can, that will help to keep a consistent level in the bowl.
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
Carbed chevy's need 4 to 7 psi.
Just go get a brand new, name brand OE replacement mechanical fuel pump as it'll provide all the fuel a rebuilt chevy V8's ever likely to require on street/weekend drags ... and don't look back. And forget the hotrod mechanical or electric pumps ... they'll need a regulator & more fittings, hoses .. leaks ... aggravation.
Just go get a brand new, name brand OE replacement mechanical fuel pump as it'll provide all the fuel a rebuilt chevy V8's ever likely to require on street/weekend drags ... and don't look back. And forget the hotrod mechanical or electric pumps ... they'll need a regulator & more fittings, hoses .. leaks ... aggravation.
Thread Starter
Burning Brakes
Joined: Sep 2005
Posts: 1,078
Likes: 0
From: Santee CA
Originally Posted by jackson
Carbed chevy's need 4 to 7 psi.
Just go get a brand new, name brand OE replacement mechanical fuel pump as it'll provide all the fuel a rebuilt chevy V8's ever likely to require on street/weekend drags ... and don't look back. And forget the hotrod mechanical or electric pumps ... they'll need a regulator & more fittings, hoses .. leaks ... aggravation.
Just go get a brand new, name brand OE replacement mechanical fuel pump as it'll provide all the fuel a rebuilt chevy V8's ever likely to require on street/weekend drags ... and don't look back. And forget the hotrod mechanical or electric pumps ... they'll need a regulator & more fittings, hoses .. leaks ... aggravation.
Ok...So fuel pressure shouldn't see higher than 15 lbs for standard street use, and a standard fuel pump should work just fine. Got it.
Thanks all!
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
Originally Posted by Sprzout
...I can get a mech. pump for about $80 tops,
Melting Slicks
Joined: Mar 2006
Posts: 3,342
Likes: 7
From: Connecticut
Does the size/depth of the pump matter?
I have a deep one on my 73'.... maybe 3" deep bowl/sump... or whatever you wish to call it
I also have a brand new leftover from some job or another which is the shallow type ...maybe 1 1/2" deep
Are these both ok to use with a street engine?
Thanks
I have a deep one on my 73'.... maybe 3" deep bowl/sump... or whatever you wish to call it
I also have a brand new leftover from some job or another which is the shallow type ...maybe 1 1/2" deep
Are these both ok to use with a street engine?
Thanks
Last edited by Bob Onit; Aug 24, 2006 at 03:07 AM.
Le Mans Master
Joined: Jan 2004
Posts: 8,295
Likes: 30
From: one night in Bangkok you are never lonely
I run a Holley fuel pump that is neat looking but really too much so I did install a regulator and gage that keeps the constant pressure at 6 lbs.
My 600 cfm carb runs just fine.
My 600 cfm carb runs just fine.
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
Originally Posted by Bob Onit
Does the size/depth of the pump matter?
I have a deep one on my 73'.... maybe 3" deep bowl/sump... or whatever you wish to call it
I also have a brand new leftover from some job or another which is the shallow type ...maybe 1 1/2" deep Are these both ok to use with a street engine? Thanks
I have a deep one on my 73'.... maybe 3" deep bowl/sump... or whatever you wish to call it
I also have a brand new leftover from some job or another which is the shallow type ...maybe 1 1/2" deep Are these both ok to use with a street engine? Thanks
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Le Mans Master
Joined: Apr 2004
Posts: 7,106
Likes: 38
From: Newark DE
Originally Posted by jackson
Carbed chevy's need 4 to 7 psi.
Just go get a brand new, name brand OE replacement mechanical fuel pump as it'll provide all the fuel a rebuilt chevy V8's ever likely to require on street/weekend drags ... and don't look back. And forget the hotrod mechanical or electric pumps ... they'll need a regulator & more fittings, hoses .. leaks ... aggravation.
Just go get a brand new, name brand OE replacement mechanical fuel pump as it'll provide all the fuel a rebuilt chevy V8's ever likely to require on street/weekend drags ... and don't look back. And forget the hotrod mechanical or electric pumps ... they'll need a regulator & more fittings, hoses .. leaks ... aggravation.
