What fuel pressure for a 454 BB engine?
Thread Starter
Team Owner
Joined: Nov 2004
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From: Sorrento Italy
What fuel pressure for a 454 BB engine?
my fuel pressure meter shows 7.5 psi but I guess its under what's advisable to have a correct flow, specially at highr revs.
what would be a suitable pressure in PSI?
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From: Sunshine Coast, Queensland, Australia
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Fuel pressure needs are determined by what your feeding.
Looks to be a Holley carb in the background there. Not the best pic, but CLEARLY not EFI. So, Holley carb. 7.5 PSI. A tad on the high side maybe, but should be just fine.
Not clear where your getting your information. Definitely NOT LOW! not for a Holley carburetor.
Now, the EFI in my car, ..... But that's an entirely different kettle of fish!
Looks to be a Holley carb in the background there. Not the best pic, but CLEARLY not EFI. So, Holley carb. 7.5 PSI. A tad on the high side maybe, but should be just fine.
Not clear where your getting your information. Definitely NOT LOW! not for a Holley carburetor.
Now, the EFI in my car, ..... But that's an entirely different kettle of fish!
Thread Starter
Team Owner
Joined: Nov 2004
Posts: 20,703
Likes: 25
From: Sorrento Italy
Fuel pressure needs are determined by what your feeding.
Looks to be a Holley carb in the background there. Not the best pic, but CLEARLY not EFI. So, Holley carb. 7.5 PSI. A tad on the high side maybe, but should be just fine.
Not clear where your getting your information. Definitely NOT LOW! not for a Holley carburetor.
Now, the EFI in my car, ..... But that's an entirely different kettle of fish!
Looks to be a Holley carb in the background there. Not the best pic, but CLEARLY not EFI. So, Holley carb. 7.5 PSI. A tad on the high side maybe, but should be just fine.
Not clear where your getting your information. Definitely NOT LOW! not for a Holley carburetor.
Now, the EFI in my car, ..... But that's an entirely different kettle of fish!
Race Director
Joined: Nov 2006
Posts: 13,143
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From: Sunshine Coast, Queensland, Australia
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Not certain what if any issues you maybe experiencing. But your fuel pressure at idle is certainly not the problem.
Perhaps your pressure above idle is a issue?
Perhaps you could clue us all in as to why your drawing these conclusions.
Perhaps your pressure above idle is a issue?
Perhaps you could clue us all in as to why your drawing these conclusions.
Thread Starter
Team Owner
Joined: Nov 2004
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From: Sorrento Italy
Race Director
Joined: Nov 2006
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From: Sunshine Coast, Queensland, Australia
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As an example. I run 60 PSI of fuel pressure.
I did indeed have some tuning issues awhile back.
I did indeed start a thread on here asking for advice on getting my tuning issues sorted.
It really didn't have anything to do with my fuel pressure. Which is still rock steady at 60 PSI.
So, thinking, maybe. Just explain what your running issues are. Just a thought.
I did indeed have some tuning issues awhile back.
I did indeed start a thread on here asking for advice on getting my tuning issues sorted.
It really didn't have anything to do with my fuel pressure. Which is still rock steady at 60 PSI.
So, thinking, maybe. Just explain what your running issues are. Just a thought.
Race Director
Joined: Nov 2006
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From: Sunshine Coast, Queensland, Australia
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And while I was typing this, you replied with that.
your AFR's at RPM's above 4K?
Just maybe your main jets are too rich?
your AFR's at RPM's above 4K?
Just maybe your main jets are too rich?
Race Director
Joined: Nov 2006
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From: Sunshine Coast, Queensland, Australia
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Wonderful thing about that under hood pressure guage. At the speeds and RPM's you are experiencing issues. Are you able to read this guage?
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Race Director
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From: Sunshine Coast, Queensland, Australia
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Your conclusions seem flawed. Run it hard, wide open, kill the engine and coast over to the side of the road. Pull a few plugs. Rich or lean?
Thread Starter
Team Owner
Joined: Nov 2004
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From: Sorrento Italy
Burning Brakes
Joined: Apr 2020
Posts: 781
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From: Western NY
For a lot of carbs including Holley you do not want pressure any higher that 7-8 psi. I would strongly suggest if you can afford it to get a fuel pressure gauge you can mount in the cockpit then you will know what your fuel pressure is all the time not just when parked with the hood open
Pat
Pat
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From: FL
If you are running out of fuel at 4k, the problem is flow, not pressure. You can only get so much fuel through the stock fuel lines.
I actually went from 58psi through the stock lines to 42 psi and a full AN-8 (1/2") line from the tank to the rails for my EFI. Runs much better.
I actually went from 58psi through the stock lines to 42 psi and a full AN-8 (1/2") line from the tank to the rails for my EFI. Runs much better.
Thread Starter
Team Owner
Joined: Nov 2004
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From: Sorrento Italy
If you are running out of fuel at 4k, the problem is flow, not pressure. You can only get so much fuel through the stock fuel lines.
I actually went from 58psi through the stock lines to 42 psi and a full AN-8 (1/2") line from the tank to the rails for my EFI. Runs much better.
I actually went from 58psi through the stock lines to 42 psi and a full AN-8 (1/2") line from the tank to the rails for my EFI. Runs much better.
Race Director
Joined: Mar 2016
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From: Napa Valley California
OP,
You haven’t given enough information about the engine, and your use of the car for anyone to help you solve your problem.
What are the engine specs and what components are you running?
You state it seems to starve for fuel at 4000 rpm.
How long are you running at 4000 rpm.
Are you racing the car, just driving on the streets or just being a street cruiser with an occasional blast?
In your picture, it looks like you are running a -6 feed line to your carburetor.
Unless you are running a 700 hp monster with an 1150 dominator Holley you are probably fine on your feed line.
You also stated you changed fuel pumps.
What did you replace the “racing” fuel pump with?
Mechanical fuel pumps are rated for “gallons per minute” and a pre set psi.
What were the specs of the new fuel pump?
Are you running a fuel regulator?
With anything other than a stock fuel system, you need one.
If you have one, what type, where is it mounted in the system and what do you have it set to?
You haven’t given enough information about the engine, and your use of the car for anyone to help you solve your problem.
What are the engine specs and what components are you running?
You state it seems to starve for fuel at 4000 rpm.
How long are you running at 4000 rpm.
Are you racing the car, just driving on the streets or just being a street cruiser with an occasional blast?
In your picture, it looks like you are running a -6 feed line to your carburetor.
Unless you are running a 700 hp monster with an 1150 dominator Holley you are probably fine on your feed line.
You also stated you changed fuel pumps.
What did you replace the “racing” fuel pump with?
Mechanical fuel pumps are rated for “gallons per minute” and a pre set psi.
What were the specs of the new fuel pump?
Are you running a fuel regulator?
With anything other than a stock fuel system, you need one.
If you have one, what type, where is it mounted in the system and what do you have it set to?
Race Director
Joined: Mar 2016
Posts: 14,282
Likes: 8,087
From: Napa Valley California
Another thing to consider is where is your timing set at?
How is the distributor set up?
Are you running vacuum advance?
Many people will chase a fuel problem but actually find their timing is set incorrectly or their distributor is not set up correctly.
How is the distributor set up?
Are you running vacuum advance?
Many people will chase a fuel problem but actually find their timing is set incorrectly or their distributor is not set up correctly.
Thread Starter
Team Owner
Joined: Nov 2004
Posts: 20,703
Likes: 25
From: Sorrento Italy
the e-curve dizzy is a nightmere to set properly on my opinion anyway.
Thread Starter
Team Owner
Joined: Nov 2004
Posts: 20,703
Likes: 25
From: Sorrento Italy
OP,
You haven’t given enough information about the engine, and your use of the car for anyone to help you solve your problem.
What are the engine specs and what components are you running?
You state it seems to starve for fuel at 4000 rpm.
How long are you running at 4000 rpm.
Are you racing the car, just driving on the streets or just being a street cruiser with an occasional blast?
In your picture, it looks like you are running a -6 feed line to your carburetor.
Unless you are running a 700 hp monster with an 1150 dominator Holley you are probably fine on your feed line.
You also stated you changed fuel pumps.
What did you replace the “racing” fuel pump with?
Mechanical fuel pumps are rated for “gallons per minute” and a pre set psi.
What were the specs of the new fuel pump?
Are you running a fuel regulator?
With anything other than a stock fuel system, you need one.
If you have one, what type, where is it mounted in the system and what do you have it set to?
You haven’t given enough information about the engine, and your use of the car for anyone to help you solve your problem.
What are the engine specs and what components are you running?
You state it seems to starve for fuel at 4000 rpm.
How long are you running at 4000 rpm.
Are you racing the car, just driving on the streets or just being a street cruiser with an occasional blast?
In your picture, it looks like you are running a -6 feed line to your carburetor.
Unless you are running a 700 hp monster with an 1150 dominator Holley you are probably fine on your feed line.
You also stated you changed fuel pumps.
What did you replace the “racing” fuel pump with?
Mechanical fuel pumps are rated for “gallons per minute” and a pre set psi.
What were the specs of the new fuel pump?
Are you running a fuel regulator?
With anything other than a stock fuel system, you need one.
If you have one, what type, where is it mounted in the system and what do you have it set to?
the car is a bit of a garage king, used just during weekends, as astreet cruiser with occasional blasts.
Race Director
Joined: Mar 2016
Posts: 14,282
Likes: 8,087
From: Napa Valley California
I’m not familiar with an e-curve distributor so I can’t help you there.
Maybe someone else has experience with them.
Unless you got timing help from forum member Lars, it’s unknown if that is good advise or not.
Not running vacuum advance on a street car can be an issue unless you really know what you are doing setting up the distributor and setting the timing correctly.
Maybe someone else has experience with them.
Unless you got timing help from forum member Lars, it’s unknown if that is good advise or not.
Not running vacuum advance on a street car can be an issue unless you really know what you are doing setting up the distributor and setting the timing correctly.
Drifting
Joined: Oct 2005
Posts: 1,527
Likes: 148
From: East London/SW Essex UK
I'm running a 950 DP generic Holley carb feeding a high 500 hp 489 cu in 4 speed - TBH stock fuel pump coped with everything the original stock 427 demanded and then with the new engine.....I entered a Hill Climb and giving the Vette full gas up a 1 in 5 short hill caused fuel starvation - the engine effectively ran out of fuel.
I put it down to the effects of ethanol content in the gas. It seemed to have degraded the diaphragm of the fuel pump (and its effectiveness) - replaced with aftermarket high volume (definately not high pressure) new fuel pump (a Holley if I recall) and problem was solved.
I put it down to the effects of ethanol content in the gas. It seemed to have degraded the diaphragm of the fuel pump (and its effectiveness) - replaced with aftermarket high volume (definately not high pressure) new fuel pump (a Holley if I recall) and problem was solved.
Race Director
Joined: Mar 2016
Posts: 14,282
Likes: 8,087
From: Napa Valley California
There should be a 4 digit number cast into the carb, like 4150 or something similar.
Find that number and then go to Holley’s website and try to match your carb up to one of Holley’s.
give us at least some better pictures of the engine with the air cleaner off so people can at least see what you have.
Find that number and then go to Holley’s website and try to match your carb up to one of Holley’s.
give us at least some better pictures of the engine with the air cleaner off so people can at least see what you have.
Last edited by OldCarBum; Oct 12, 2024 at 11:01 PM.