88v8 Ivor Duarte Gloucestershire UK (1041 posts) Registered: 02/11/2010 04:29AM Main British Car: 1974 Land Rover Lightweight V8 |
Fuel pressure now and then.
A Holley carburettor reconditioner ... we had a brief exchange about fuel pressures.
My shop manual of 1963 specifies a min pressure of 4 psi. I saw video of him running an engine at 3 psi. He said ' It has to do with the leaded fuel weight and properties vs Ethanol or alcohol based fuel of today'. First I heard of this. Have been unable to find other references to lowering the window of acceptable fuel pressure. I am setting up a Filter King to ensure I have the correct pressure. Could ask Holley, but our here in the real world what do we think? Ivor |
MGBV8 Carl Floyd Kingsport, TN (4514 posts) Registered: 10/23/2007 11:32PM Main British Car: 1979 MGB Buick 215 |
Re: Fuel pressure now and then.
Are you running 100% methanol or E85? If running E10 pump gas, IMO it is not an issue. I run 7psi in my Holley double pumper (Camaro).
This article mentions a vacuum-referenced pressure regulator for use in racing with alcohol. Quote: |
88v8 Ivor Duarte Gloucestershire UK (1041 posts) Registered: 02/11/2010 04:29AM Main British Car: 1974 Land Rover Lightweight V8 |
Re: Fuel pressure now and then.
Just running pump gas. The ethanol content is not disclosed to us poor customers, but between zero in some Super brands, and 5%.in cooking gas.
We do have E10 in some filling stations but I don't use it. Ivor |
joe_padavano Joseph Padavano Northern Virginia (157 posts) Registered: 02/15/2010 03:49PM Main British Car: 1962 F-85 Deluxe wagon 215 Olds |
Re: Fuel pressure now and then.
The only issue would be the specific gravity of the fuel as it related to buoyancy of the float in the carb. Of course, I'd reset the float level instead of changing the fuel pressure, but the result would be the same. You need to be sure the needle closes with the correct level in the bowl. Of course, with a Holley, you can just adjust the float level with the engine running, so why even mess with the fuel pressure?
|
BlownMGB-V8 Jim Blackwood 9406 Gunpowder Rd., Florence, KY 41042 (6470 posts) Registered: 10/23/2007 12:59PM Main British Car: 1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS |
Re: Fuel pressure now and then.
Rate of delivery can be a factor. At 6 psi fuel can flow into the carb twice as fast as it can at 3 psi.
Jim |