Certain parts of an automobile never get any love. Unlike the TURBOCHARGER, the SUSPENSION, or the HEMI motor (all said with Jeremy Clarkson enthusiasm), some automotive parts—that are essential to the performance of your car—can potentially be overlooked. One of these essential parts—which can control the performance of your vehicle—is the fuel-pump, and more specifically, installing a high-pressure fuel pump to handle the demands of a motor pushing more power than stock.
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The two most common types of fuel pumps are mechanical and electric. If you’re using a carbureted setup for the street, a mechanical fuel pump is usually great for anything under 500 horsepower as they’re reliable, easier to install, and don’t require wiring. Carburetors work best by running a lower PSI, high volume (general consensus is around 7 PSI without the need of a regulator) so you don’t’ overfill the carb with fuel. Mechanical pumps are limited in their ability to pump so it’s usually not a concern.
A simple way to think about the difference between mechanical and electric fuel pumps is high pressure/low volume for mechanical and low pressure/high volume electric setups.
On the other hand, if you’re running a carbureted setup with high-horsepower or a fuel-injected setup (with the exception being a mechanical fuel-injection setup), you’ll most likely have to upgrade to an electric fuel pump.
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(Okay, there are a few more type of pumps, such as belt-driven for extreme performance applications up to 3,000 horsepower, and diesel pumps, but we’ll leave those out for now).
Once you start to make more power, the need to feed your engine with more fuel is inevitable. Electric fuel pumps are able to pump faster with higher flow rates more efficiently than traditional mechanical units.
Electric fuel pumps are “pushers,” which sit either right outside the fuel tank/cell on a frame rail or secure body panel, or they are inside the tank/cell. They work most effectively close to the fuel source, and putting them closer to the motor can actually be prohibitive to producing power and efficiency.
Luckily, companies like Aeromotive, Edelbrock, and others are chock full of detailed information, schmatics, and diagrams to inform you on the other critical components of the fuel system you will need: accumulators, filters, etc.. Be sure to get yourself up to speed with the entire fuel system so you can not only upgrade your HPFP, but the system as a whole as your project progresses.
High-pressure fuel pumps solve the problem of not feeding your motor enough fuel by delivering a tidal wave of gasoline via a higher GPH (gallons per hour) and a faster speed via PSI (pounds per square inch) to your engine than stock. Aftermarket high-pressure fuel pumps can handle much more power and as you upgrade power adders, it’s important to not forget the rest of the system. Fuel pumps may not be as sexy as superchargers, but they’re just as important. *As a side note: be sure to also upgrade your fuel lines if the stock ones can’t handle the upgraded flow.*
So how do you know which fuel pump to get? As a general rule of thumb, always be conservative with your horsepower numbers but err on the side of getting a fuel pump that can handle more horsepower than it needs to.
Some key variables you will need to figure out are: flywheel horsepower, engine fuel efficiency (otherwise known as BSFC (brake specific fuel consumption)), and maximum fuel system pressure and the pump’s flow volume at that voltage.
There’s a simple formula you can use to figure out which pump works best for your application, though we do recommend getting a second opinion from an engine tuner or specialist before you make the leap.
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Depending which type of motor you have—naturally-aspirated, nitrous, or forced induction—the BSFC will usually be .45-.55; .5-.6; and .6-.75; respectively. Using those numbers, you plug them into the following formula based on the standard weight of a gallon of gasoline, which is roughly 6 pounds.
If you have a 700 horsepower turbocharged motor, the formula will be:
700 x .75 BSFC = 525 pounds of gasoline
525 / 6 = 87.5 GPH (gallons per hour)
High-pressure fuel pumps are the key to making your engine sing once you’ve begun to add more and more power. Like exercising heavily without drinking water, you don’t want to starve your motor of the quench it requires. The vascular system of the car, fuel and fuel pumps are akin to getting an adrenaline shot via the throttle. Keep that engine humming with a high-pressure fuel pump and you’ll see increased horsepower, torque, fuel economy and overall performance benefits.
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