How to Choose an Electric Fuel Pump
When it comes to choosing an electric fuel pump for your engine, the choices are absolutely endless. Where do you start? Which pump is the right one for you? Watch this and find out!
One of the first things you'll need to determine is what operating pressure you need for your particular setup. Do you run a carburetor? Electronic fuel injection? Carburetors typically operate with pressures from 2 to 9 psi, modern EFI systems generally run best from 40 to 60 psi, and the actual pump design itself often dictates both performance and cost.
The most common pump designs are diaphragm pumps, vane pumps, G-rotor pumps, and screw pumps. Fuel pump manufacturers advertise their free-flow rate in unrestricted gallons per hour or pounds per hour. To make the right choice, you'll need to consider fuel pressure and its relationship to fuel volume. They're inversely proportional – as the fuel pressure increases, the flow rate drops. An EFI engine will require a higher-capacity pump than the same engine would if it was carbureted – even though both are using the same amount of fuel. Another design option to consider is whether you use an in-tank or inline-style setup. In-tank pumps benefit from the cooling effects of the pump being in the tank; inline pumps are easier to replace and usually less expensive.
Numerous factors determine which is the best pump for you – horsepower, brake-specific fuel consumption, fuel type, system-pressure requirements, filtration, and supply voltage. To select the right pump for your application, first determine your engine's maximum horsepower, either by dyno-testing or by using your manufacturer's advertised horsepower rating. To be safe, stay on the high side.
Next, consider your brake-specific fuel consumption, which is the amount of fuel consumed per unit of power produced. Most naturally aspirated gas-burning engines operate at 0.4-.0.5 pounds per horsepower per hour. Nitrous engines are slightly higher, about 0.5-0.6, and forced-induction (supercharged or turbocharged) engines are the highest, about 0.6-0.75. Fuel type is another factor – ethanol engines use 30-35% more fuel than gas-burning engines, and methanol (alcohol) engines as much as 100-200% more. You'll also want to keep in mind the weight of your fuel. (A gallon of pump gas weighs about 6 pounds.)
Some fuel pumps – typically those used with lower-pressure applications – regulate the pressure themselves. Higher-pressure systems usually need an external pressure regulator to maintain the proper operating pressure for your setup.
Most EFI systems work best with a return-style setup. It allows the pump to constantly circulate fuel, which helps eliminate air pockets and cools the pump as the fuel flows through it. Just be sure to run the dip tube below the fuel line to prevent aeration of the fuel in the tank. "Deadheading" can cause pressure oscillation and can create excessive heat at the pump due to the forces acting against it as it tries to deliver the fuel. Filtration is another important component of any fuel system. A 100-micron high-flow pre-filter, such as Holley's HydraMat, are the standard of the industry. For post-filters, a 10-micron filter is usually adequate for EFI setups and a 40-micron setup for carbureted applications.
So whatever your engine manufacturer, your preferred fuel, your fuel-system type, or your choice of pump style, this informative video will be eight minutes well-spent and a great place to start!
Find details on the complete line of Holley fuel pumps, regulator, filters, and components here.
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