Fuel Pressure
 

Looking for feedback on fuel pressure settings with a 327 and a Quadrajet for stock and what differences you may have seen running a higher number for et and mph.

Re: Fuel Pressure
 

I have a super stock car with that combo. I run 6 lbs of fuel pressure. 8600 rpm in the lights at 130 mph. Volume is more important than pressure. You need at least a gallon of fuel in 30 seconds or less at the carb.

Re: Fuel Pressure
 

Agreed. Unfortunately, a Q-Jet has only one needle and seat.

Re: Fuel Pressure
 

Mark, I run that exact combination...no difference from 5 1/2 to 7 lbs. Mine will vary about half a pound depending on the fuel. Adequate volume is the key. A bypass regulator or a pump that can bypass can help stabilize the fuel pressure and keeps the fuel cooler. -Al

Re: Fuel Pressure
 

thanks to all who replied, I use a BG 280 with #12 line from the fuel cell to the pump #10 line to the regulator and #8 line from the regulator to the carb. My question was, does fuel pressure say set at 6 , 6 1/2 or 7 psi have any effect. And how much fuel pressure can the needle and seat withstand.

Re: Fuel Pressure
 

The higher the pressure goes the more strain on the needles and seats to do their job! I run 6 1/2 lbs. on my Quads and Thermo.
I have run 8 lbs. without a noticeable difference in performance if jetting is in the ballpark.......
But it triples my needle and seat issues!

Re: Fuel Pressure
 

Many years ago when I was racing,I found thru GM parts a needle and
seat that was used for motorhomes. We put that on a tow vehicle and
it cured some issues for us. Don't know if that is still available but it
would be something to think about.

Re: Fuel Pressure
 

Dean Oliver may respond on his own (if he sees this string), but he helped me overcome a problem I had with richness and smoke at idle and low speeds (e.g. driving around the pits). I checked and rechecked everything with my Q-Jet 305, including even fiddling around with various fuel pressure settings, and the problem would not go away. I called Dean and almost the first question he asked was "Which needle and seat is in the carb"? I told him it's the extra-super-big one that Edelbrock sells, and he told me to remove it and go to the next size smaller. His explanation was that there is so much fuel flow through the big Edelbrock needle and seat that the incoming fuel actually partially overcomes the ability of the needle to close completely, which functionally raises the float level and causes flooding. He also said that with any "normal" racing fuel pressure, the fuel enters the bowl so violently that it keeps the fuel in the bowl all "stirred-up". I changed to the smaller needle and seat and the condition is gone.