Thread: Changing from mechanical fuel pump to electric

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Originally Posted by Yellow72

Just curious why you want to change to an electric pump?
Mechanical pumps will easily support 600-700 carbureted horse power.

Yellow 77. Good question. I was given one as a gift and want to do some changes to the car. Buy the way it's a Holly Red Elec fuel pump.

I have had Stewart Warner electric fuel pumps on my cars for over 12 years and never any problems. They make a 6 volt and a 12 volt pump, no return lines. I have a pressure regulator on the 57 but it probably doesn't need one. No pressure regulator on the 34 Plymouth. Pressure max is about 7 psi, and the regulator on the 57 is set for about 5 psi.

Just to be safe I do carry a spare pump in case one would fail but only because of the age of the pumps, not the quality of the units.

Originally Posted by Jim Standley

Yellow 77. Good question. I was given one as a gift and want to do some changes to the car. Buy the way it's a Holly Red Elec fuel pump.

The red is to small.

To small for street use only ?

From a previous post of mine ............

The Mallory pumps are Gerotor type. The Holley blue, red, and blacks series are rotary vane type pumps. Gerotor pumps are much more rugged than RV pumps and also have superior suction qualities over RV pumps in general. And, surprise surprise, the Gerotor pumps are more expensive. Holley also makes Gerotor pumps and they are slightly less expensive than Mallory pumps according to what I've seen on Summit.

My suggestion for purchasing electric pumps;

1) Buy a Gerotor style pump
2) Use an oil pressure cut off switch with it if possible
3) Don't use too much pump. For gasoline, natural aspiration you need 8-9 GPH (at 4-7 psi) per 100 hp.
4) For max perfromance and cool factor buy a pump with 12-14 psi and use a bypass style regulator with return line. This will make it very hard for you to overheat the pump or experience vapor lock.
5) Use 15-30 mic screen before pump and 10 mic filter after pump.
6) Use minimum 3/8 line suction and supply/return. Avoid 90 degree elbows close to carb, curved tubing or hose better
7) Mount pump using 3/16 rubber pad to frame
8) Use a relay switch with the pump. You may also want to use a hidden toggle for added theft prevention

I think that gets most of it. If you already have a rotary vane pump go ahead and use it.

The Holley red pump supports 425 HP ............

Kitz

I would recommend the Carter P4070,they are not noisy like the Holley & Pro-Comps'.No matter which one you get buy a wiring kit with relay and a good filter to go between the tank and pump.Speedway tells you not to use a paper element filter,Good Advise! I found out the hard way,junk Fram's paper element sucked into inlet and burned up a new Holley pump in less than 2 hours

The Holley Red should be more than enough for up to 650+/- horsepower. The formula for determining flow (in gallons per hour) is as follows:
HP/2 = lb/hr
lb/hr / 6 = GPH
multiply GPH x 1.15 to provide a margin of safety

So 650/2 = 325
325/6 = 54.166
54.166*1.15 = 62.3 GPH