gkull

I only run my Demon carb at 6 psi with a mechanical pump with a return line system. I got into a discussion with a friend about the correct pressure to use. He claims 10 psi is the best. I couldn't find an article to prove it one way or the other. I just thought that 6-8 psi is plenty and much easier on the needle and seats.

Twin_Turbo

10 psi sounds way too high, that's what tbi systems run at. I'd say 4-6 psi is plenty.

Red73

George, I run the same as you, 6 psi with return. Rod

rainman69

6-8 psi is what I've heard. IIRC, the stock '70 LT-1 fuel pump put out 7+ psi and good to 6500 RPM.

ram82fire

Six psi is more than enough . flow is the name of the game when it comes to carbs . You are right on target GK .

gman :crazy:

ED DINAPOLI

Holley spec on their carbs is not to exceed 9psi or you will force fuel past the seat. Q-jet will only hold 7 psi. I dont know what Demon offers as a spec. 6 psi is a good rule of thumb.
Ed

Tominator

This is from the Edelbrock web page:

Fuel Pumps and Pressure
Avoid extremes in fuel pressure. At IDLE, there should not be any more than 6.0 psi; if the vehicle has an adjustable fuel-pressure regulator, set it to 5.5 psi. With most fuel pumps the minimum fuel pressure is encountered at high rpm and WOT. Fuel pressure should not drop below 2.0 psi. If it does, a fuel pump with more capacity may be required. Note that some later model vehicles (the 5.0L Ford is one example) have mechanical pumps that will give more than 6.0 psi at idle. The vehicle will perform well, but may be prone to stalls on quick turns and stops with the clutch disengaged. If this problem occurs, check the fuel pressure. If it is more than 6.0 psi at IDLE, it should be reduced through the use of a regulator, such as Edelbrock #8190, or by creating a restricted by-pass bleed to the fuel return line. Edelbrock Street Fuel Pumps are highly recommended for all Edelbrock Performer Series carburetor installations.

honaker

"Holley spec on their carbs is not to exceed 9psi or you will force fuel past the seat. Q-jet will only hold 7 psi. I dont know what Demon offers as a spec. 6 psi is a good rule of thumb."

:iagree: