While fuel pumps can be adjusted, the process applied largely depends on the type of fuel system in place and the design of the pump itself. Most high-performance vehicles have adjustable fuel pumps or external fuel pressure regulators that allow modification of fuel pressure to meet specific demands of the engine. Most common-place fuel pumps deliver a certain range of pressure, typically within a scope of 30-80 psi depending on the model, but for performance modifications, usually custom settings are required to make sure that air-fuel ratio is at an optimum level.
In engines with adjustable fuel pressure regulators, technicians can change the manner of fuel delivery by changing the pressure setting. For instance, a turbocharged engine may require well over 80 psi to maintain fuel flow under high boost conditions, while a naturally aspirated engine may require little more than 40 psi. Adjustments in fuel pressure directly affect the performance of the engine since if the fuel pressure is low, then it may cause a lean condition and maybe with a result of engine knock. Higher pressure ensures sufficient fuel at high RPMs. Correct adjustment can enhance up to 10% of the overall engine efficiency to support a smooth and powerful drive.
Fuel pumps in carbureted engines can be adjusted by modifying the float level in the carburetor. It indirectly meters the quantity of fuel available in the bowl to the engine. This, of course, will have to be carefully tuned, because too much will lead to flooding and a poor idle, while too little can lead to hesitation upon acceleration. Most independent high-performance owners working with carbureted engines use it to fine-tune fuel delivery according to their specific needs.
Changes to fuel pumps in electronically fuel-injected engines normally come through the ECU. Tuning of the ECU will allow the technician to set the performance of the fuel pump to the increased demands of horsepower. It would also ensure smooth and continuous fuel flow at high speeds. Such a setting normally requires specialized software and expertise, since incorrect settings may lead to failure or further damage. These methods are most used by performance tuners who want to ensure the fuel pump will support a higher power output without sacrificing reliability.
As car designer Carroll Shelby once said, "In racing, there's always a next level." That may well involve adjusting a Fuel Pump as part of that journey, looking to optimize performance and efficiency further. Check out Fuel Pump for more about high-quality, adjustable fuel pumps.