Not all fuel pumps are alike; design, pressure ratings, and application vary. Application also varies due to different engine requirements: mechanical, in-tank electric, and external electric pumps. Most of the older, carbureted engines feature mechanical pumps, which operate at low pressures, normally less than 10 psi. Per contrast, modern fuel-injected engines have electric fuel pumps that run at much higher pressures of 30 to 60 psi, required to keep efficient fuel injection and combustion processes going.
Performance fuel pumps also differ from standard pumps in that they are designed to support high-powered or modified engines, which require greater fuel flow. High-performance pumps deliver up to 255 liters per hour or more, for instance, which is important because turbocharged or supercharged engines need the extra amount of fuel to avoid fuel starvation. A standard pump will lead to such fuel delivery problems and hence a reduction in horsepower and efficiency of such an engine. Yet, performance fuel pumps tend to be pricier: upwards of $300 or more versus regular ones that cost about $50 to $200.
OEM fuel pumps also differ from their aftermarket counterparts. OEM pumps are strictly to the standards set by the manufacturer, usually to specs with that of the vehicle for guaranteed reliability and durability. Aftermarket pumps, though, vary in quality even if at somewhat cheaper prices. Brands such as Bosch and Delphi manufacture their pumps to OEM standards, while the majority of other brands vary in quality. For these reasons, several of the cheaper aftermarket pumps do fail prematurely, raising the frequency and costs for replacements. Data support that over 30% of car owners go for an aftermarket pump in order to cut costs, although the quality from those may be questionable.
The fuel pumps of modern vehicles are mostly in the category of electric in-tank. Electric in-tank provides silent operation, and better cooling takes place since the fuel inside the tank regulates temperature. External electric pumps, like those commonly used on high-performance vehicles or modified vehicles with respect to performance, are easier to access and generally capable of higher pressures but noisier. The correct pump type would depend on the fuel pressure requirement of the engine and the purpose of the vehicle. As Automotive expert John Peterson points out, “Correct selection of the fuel pump is very crucial to performance and durability of the engine.”
Fuel pump specifications such as flow rate, pressure, and compatibility make proper selection imperative in such cases. Poor selection may cause problems in the performance of an engine, mileage, or even pump failure. For learning about fuel pump types and options, refer to the page Fuel Pump.