The capacity of the fuel pump is basically the amount of fuel the pump can supply to the engine within a fixed period of time and is normally measured in hours per liter. The common conventional fuel pumps in normal vehicles have their usual capacities within a range of 90 to 120 LPH and will serve standard engines with normal fuel requirements. However, high performance engines require high-flow fuel pumps, where the capacity ranges from 255 to over 400 LPH depending on the type of modification and horsepower.
Capacity is essential in the engine to ensure fuel supply to the engine remains constant for continuous combustion. If the fuel pump capacity can meet the engine’s requirement, the latter can work fine whether the car is in acceleration or driving at a high speed. For instance, if an engine boasts of over 400 horsepower, it needs at least 300 LPH for its pump to prevent starving of fuel in the engine that could lead to knocking or even damage to the engine.
Fuel pump capacity also influences fuel pressure, another very critical factor in fuel injection systems. In most modern applications, the fuel pumps run at about 58 psi, but high-flow fuel pumps may operate at much higher pressures to realize high delivery rates. Capacity, therefore, must match the fuel pressure requirements of the engine so that the fuel injectors can act appropriately. If this required quantity exceeds the capacity of the fuel pump, then low fuel pressure, poor fuel atomization, low power, and poor fuel efficiency will result.
The capacity of fuel pumps is often tested under controlled conditions by many manufacturers and then specified. In reality, however, actual capacity may be affected by such variables as altitude, temperature, and fuel quality. According to specialists, a capacity 10-15% higher than what actually has been theoretically calculated for the given engine demand should provide adequate leeway for any unexpected condition that may be encountered.
What is Fuel Pump Capacity? The Fuel pump capacity could be the capacity of a fuel pump to provide the required amount of fuel to the requirement so that it can support the good performance of an engine. Matching of capacity to the engine demand and consideration of operational condition are helpful for reliability of delivery of fuel, hence fostering optimum power and longevity across all driving scenarios.