When you’re looking to make more horsepower, we know we need more air and fuel into our engine. That can be accomplished many ways such as upgrading your fuel injectors, exhaust system, air intake system, and big carburetors. The list goes on, but none of those parts can do their job unless they’re supplied with enough fuel. To help ensure the proper fuel volume and pressure you have to start at the source, the fuel pump.
How does a fuel pump work?
A fuel pump transfers fuel throughout your system to the necessary components so your vehicle can run. Your pump draws fuel out of the tank through a pipe to the carburetor, & this is done with a vacuum suction. From there it sends the fuel to the fuel line and into the fuel rail where it can be injected into the cylinder. A fuel pump also has other components such as a filter, and a float. A float helps read what level your fuel is at.
Performance Fuel Pumps
Performance fuel pumps generally flow more fuel, and tolerate higher pressures than stock fuel pumps. It’s important to pay attention to the specs when upgrading your fuel pump to ensure your vehicle will receive the proper amount of fuel. Performance fuel pumps are flow rated in Gallons Per Hour (GPH) or Liters Per Hour (LPH). A naturally aspirated engine needs about 0.5 lbs. of fuel per horsepower per hour. A forced induction engine, or an engine with nitrous needs about 0.75 lbs. of fuel per horsepower per hour. If you know you’re engine’s approximate horsepower, this can be easily calculated to help you determine which pump you need. You would multiply the horsepower by either 0.5 or 0.75, then divide the result figure by 6.2, which is the weight in lbs. of a gallon of gasoline. We have provided two examples for you based on this formula.
This formula determines this vehicle will need a pump that flows a minimum of 97 GPH.
Mechanical vs. Electric Fuel Pump
When searching for a new fuel pump you will come across two different types. There are Mechanical Fuel Pumps and Electric Fuel Pumps.
Mechanical fuel pumps are more commonly found on older vehicles. They are still widely used in the automotive industry due to their convenience and cost. Mechanical pumps are quiet, and require minimal effort to install. Additionally, you have no wiring to worry about. For most carbureted fuel systems most performance mechanical fuel pumps will handle an engine rated under 450 HP just fine. There are several mechanical pumps that flow as much as 130 GPH, with larger inlet and outlet ports to handle the volume. Lower GPH mechanical pumps typically deliver fuel at the low pressure that is ideally suited for a carburetor, about 6 psi, but larger GPH pumps may have to be used with a regulator to reduce fuel pressure.
If your vehicle is turbocharged, running nitrous, or you have a higher horsepower you will most likely need an electric fuel pump. An electric fuel pump is a computer system that is used to regulate the rate flow and how high the pressure is. Electric pumps offer a larger variety of flow rates and pressure outputs vs. a mechanical pump. The most common electric pump requires a 12-volt circuit with the use of a relay that gives you multiple shut off options. Additionally, there are in-tank and external electric fuel pumps. Many external electric pumps are gravity fed and are simply designed to push fuel. With this specific type of pump, it’s important that they are mounted properly. They should be placed below and close to the gas tank.
Common Questions & Answers
Q: Can I purchase a fuel pump with a higher GPH then my vehicle currently needs?
A: It’s okay to install a fuel pump that flows more than what your engine needs. If the difference between the required volume and pump output is too great, the excess can be returned to the tank via a pressure regulator.
Q: Can I purchase a pump with a lower GPH then my vehicle currently needs?
A: It’s important to never use a pump with less GPH then your vehicle needs. That will cause fuel starvation. Not only will fuel starvation cause poor performance, but potential engine damage from running too lean.
Q: Can I convert from a mechanical to an electric fuel pump?
A: Absolutely! Plates are available for most popular applications which will seal off the engine block’s mechanical pump opening.
Q: How can I monitor my fuel pressure and Air Fuel Ratio?
A: If you’re concerned about the fuel pressure and Air Fuel Ratio (AFR) then you can install gauges into your vehicle that can monitor these levels.
Q: Do I need a special fuel pump to run E-85?
A: Most fuel pumps are designed for use with gasoline, but some are ethanol compatible. Other fuel pumps can be used with alcohol and gasoline racing fuels. It’s important to read the specs of the fuel pump your looking into to ensure it will work properly with your fuel.
Now that you know all about fuel pumps and their differences, we will leave you off with a few reputable companies that manufacture performance fuel pumps.