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What do you run your fuel pressure at?

Posted By: 70satelliteguy

What do you run your fuel pressure at? - 04/29/10 12:20 AM

What is ideal? Does it depend at all on HPlevels or if you run a small or large motor? I know too much car flood the carb at low rpm but can it also cause a high speed miss? I am running 7-1/2 lbs. but someone told me that is too much!
Thanks Mike
Posted By: rickstershemi

Re: What do you run your fuel pressure at? - 04/29/10 12:23 AM

Thats what i ran in the roadster 565" 15-1, 900+hp, 7500rpm, 1250 APD Dominator.....ran like watch

Rickster
Posted By: Dabee

Re: What do you run your fuel pressure at? - 04/29/10 12:27 AM

5.5 on 511 in my street car running a Quik fuel 1050. 6.5 on the 493 in the RED running a Dominator.
Posted By: dusturbd340W5

Re: What do you run your fuel pressure at? - 04/29/10 12:27 AM

mine is set at 8 1/2 lbs
Posted By: Hemiruss

Re: What do you run your fuel pressure at? - 04/29/10 12:44 AM

Sorry to break in Rickster...M/T your inbox
Posted By: dartman366

Re: What do you run your fuel pressure at? - 04/29/10 12:52 AM

8.25 here,,no problem's, but I run a bypass system.
Posted By: MR_P_BODY

Re: What do you run your fuel pressure at? - 04/29/10 12:53 AM

7 1/2 to 8 psi is about all the needle and seat can
hold on a calibrated gauge... most people never check
their gauge accuracy so they believe the number they
see to be correct.... maybe it is, maybe it isnt...
but from flowing fuel pumps for Chrysler for a few
years thats the spec to shoot for
Posted By: '72CudaRacer

Re: What do you run your fuel pressure at? - 04/29/10 12:56 AM

7.5 lbs is not too much as long as your floats and needle & seats are good. Mine is set at 8 lbs 440 w/ 1050 dominator.
I found out a long time ago that just because someone tells you something won't work, don't mean it's so. Might not work for them, until you try it for your self, you won't know if it will work for you or not.
Lots of folks kept telling me a 4.56 gear was not enough gear to get my heavy car moving...

Brian Dunnigan

Attached picture 5952752-PinksAllOutCharlotte42009037.JPG
Posted By: VernMotor

Re: What do you run your fuel pressure at? - 04/29/10 01:18 AM

My gage says 8 1/2
Posted By: dusturbd340W5

Re: What do you run your fuel pressure at? - 04/29/10 01:20 AM

Quote:

mine is set at 8 1/2 lbs


this is also a bypass system
Posted By: dennismopar73

Re: What do you run your fuel pressure at? - 04/29/10 03:56 AM

set pressure at the point of blowing needle seat/ then back off 1/4 turn
no need no gauge
Posted By: dave571

Re: What do you run your fuel pressure at? - 04/29/10 04:07 AM

As long as you have fuel pressure in the supply line, when you are riding it hard, you've got enough.

The fuel in the carb, isn't under any pressure when it's delivered to the engine(other than atmospheric)

The fuel pump only keeps the bowls full. A steady 5 psi, is all you need. THAT said, more doesn't hurt, or gain you anything as long as the needle and seat can contain it.

As long as the pressure stays up, you have enough fuel delivery for the carb.

FWIW, I run 5 psi with a dead head style regulator. 1/2" supply line with a holley blue pump.
Posted By: moparacer

Re: What do you run your fuel pressure at? - 04/29/10 04:16 AM

6 psi deadhead Mallory Comp 250 pump and regulator.

1050 Dominator.
Posted By: rebel

Re: What do you run your fuel pressure at? - 04/29/10 05:20 AM

guage says 9 & so does the logger but it drops to 7 on WOT. dead head reg with bypass on the pump.
Posted By: The Shocker

Re: What do you run your fuel pressure at? - 04/29/10 10:47 AM

I have mine set at 7 1/2 psi by the gauge.I double checked my gauge with air pressure against a regulated shop air gauge .Mine is either dead on or its exactly off the same as the air gauge was.I turned mine up to 8 psi once and it tried to over power the needle and seats in the Demon ...
Posted By: MR_P_BODY

Re: What do you run your fuel pressure at? - 04/29/10 01:43 PM

Quote:

guage says 9 & so does the logger but it drops to 7 on WOT. dead head reg with bypass on the pump.



And when was the last time you had the transducer
calibrated ... when I was working I had to cal the
transducers every time we put them on a car... a
transducer goes out more than a gauge.... the problem
I have now is I dont have access to the cal equipment
anymore so I have to take what I have.... the gauges
are real close but I cant say about my transducers
Posted By: rebel

Re: What do you run your fuel pressure at? - 04/29/10 06:51 PM

[quote
And when was the last time you had the transducer
calibrated ...


i thought a transducer was a thing that turned someone into stone like on the "Rocky Horror Picture Show" movie. the only calibration is checking the logger reading against the guage & since both read the same at idle & WOT we use that info. i'm on my second fuel press guage & it seems to read the same as the first. the sensor itself is military spec so i doubt it's going to vary it's readings by a great amount & it never comes off the car even when pulling the engine so not much of a chance it's going to get knocked about.
Posted By: 540DUSTER

Re: What do you run your fuel pressure at? - 04/29/10 07:09 PM

if you increace the pressure at the reg. you decrease the volummn of fuel that will flow thru it.The pressure before the regulator is the place you want high pressure.NObody seems to care what happens before the regulator in a dead head system.
Posted By: MR_P_BODY

Re: What do you run your fuel pressure at? - 04/29/10 08:13 PM

Quote:

if you increace the pressure at the reg. you decrease the volummn of fuel that will flow thru it.The pressure before the regulator is the place you want high pressure.NObody seems to care what happens before the regulator in a dead head system.



True... pressure is a by product of flow VS restriction
Posted By: rickstershemi

Re: What do you run your fuel pressure at? - 04/29/10 09:18 PM

Quote:

if you increace the pressure at the reg. you decrease the volummn of fuel that will flow thru it.The pressure before the regulator is the place you want high pressure.NObody seems to care what happens before the regulator in a dead head system.



I run 22# at the pump and 7.5# at the reg

Rickster
Posted By: Quicktree

Re: What do you run your fuel pressure at? - 04/29/10 09:23 PM

mine is at 9 or a little more. anything less and it ran out of fuel in the 1/4. no problem with the needle and seat
Posted By: fury413rb

Re: What do you run your fuel pressure at? - 04/29/10 09:38 PM

8.5 with a bypass on a Holley Black with a Jegs billet return reg
Posted By: dc426

Re: What do you run your fuel pressure at? - 04/29/10 09:40 PM

7 dead head on mine.
Posted By: MR_P_BODY

Re: What do you run your fuel pressure at? - 04/29/10 10:22 PM

Quote:

8.5 with a bypass on a Holley Black with a Jegs billet return reg



A by pass doesnt have anything to do with it... pressure
is pressure BUT a by pass (return style) keeps a
more constant pressure (and cooler fuel)
Posted By: fury413rb

Re: What do you run your fuel pressure at? - 04/29/10 11:34 PM

Quote:

Quote:

8.5 with a bypass on a Holley Black with a Jegs billet return reg



A by pass doesnt have anything to do with it... pressure
is pressure BUT a by pass (return style) keeps a
more constant pressure (and cooler fuel)




easier on the pump too
Posted By: Cab_Burge

Re: What do you run your fuel pressure at? - 04/30/10 03:25 AM

I use to run 9.5 lbs with my Magnafuel 300 pump, I let it down to 5.5 lbs after talking to the Magnafuel techs and the car runs the same My message is some systems don't need as much pressures as others. I have seen systems like Brads that made the car go faster(not running out of gas)by turning up the pressure on the regulators to 9 or 10 lbs, especaiily the small original early Holley regs
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