Need a new fuel pump. How many GPH do I need

69 Mach I · #1 (**permalink**) 03-07-2005, 11:10 PM

I have a 351W putting down about 450 hp at the fly. Carb is a Holley 650 CFM. I am looking at a mechanical Holley and have a choice between 110, 130, and 170 GPH. All are priced about the same. What is the best application for my car

Ron61 · #2 (**permalink**) 03-08-2005, 06:12 AM

Assuming the fuel pump puts out the correct pressure and you won't need a regulator between it and the carb, I don't see why you would need more than the 110 unless you plan to race it wide open all the time. Figure out how much fuel you would use by doing a mile per gallon calculation. I use an electric Holly Blue Race pump that flows less than that and have never had a problem and I drive my car fast. But I do have to run a regulator as this pump puts out 14 pounds of pressure and the Holly carbs like from 7 to 10 pounds. I have mine set at 8 pounds.

Ron

69 Mach I · #3 (**permalink**) 03-08-2005, 06:24 AM

Quote:

Originally posted by Ron61

Assuming the fuel pump puts out the correct pressure and you won't need a regulator between it and the carb, I don't see why you would need more than the 110 unless you plan to race it wide open all the time.

Ron

I do like to get to the Autobahn from time to time. I know that with respect to cards, too much of a good thing just bogs you down. Is the same true with respect to pumps?

Ron61 · #4 (**permalink**) 03-08-2005, 07:00 AM

Pretty much. Check and see what pressure your fuel pump puts out. My Holly Blue Pump has a 110 free flow rating and as stated I have the pressure set around 8 pounds. At WOT it remains around 7 pounds. If you have to much pressure you will cause problemsin the carb. so make sure what the pressure is. I really doubt if you engine will burn 110 galon per hour. What kind of pump do you have on it now and is it working to your satisfaction?I run a built out 850 double pumper on mine. If you do run out of fuel at top end, it could be a carb setting or size as well as lack of fuel.

Ron

69 Mach I · #5 (**permalink**) 03-08-2005, 07:07 AM

Quote:

Originally posted by Ron61

What kind of pump do you have on it now and is it working to your satisfaction?I run a built out 850 double pumper on mine. If you do run out of fuel at top end, it could be a carb setting or size as well as lack of fuel.

Ron

Ron. Thanks for the input so far. I have a Scott Drake on there now and feel like at top end, I am not getting as much fuel as I require. I will go for the 110. The next question is whether the Edelbrock performer fuel pump is a better pump than the holley.

Ron61 · #6 (**permalink**) 03-08-2005, 07:24 AM

Now you will get arguments both ways. Some people like Holly and others like the Edelbrock. I have found them both to be good but prefer the Holly myself. And if you are running out of fuel at high speed, have the carb checked and be sure it is jetted and set correctly. They have all kinds of math formulas for figuring out carb sizes, but I go by my engine builders recommendations, and it seems they always go to larger carbs than the formulas say. If you could find a 700 or 750 Carb just to bolt on and try, that might give you an idea if it is the pump or carb.
I am guessing that you have already checked the float levels in your carb. and maybe also tried changing to larger jets. Also check your fuel filter and be sure it isn't getting a little dirty.

Ron