The fuel pressure of your engine depends on the type of fuel application that the engine uses and, overall, the power output that it is supposed to produce. With most current fuel-injected engines, you would want to run in the range of 40 to 60 PSI for efficiency. This pressure ensures fuel is delivered at the right rate to ensure optimal combustion, especially when one is trying to accelerate or when the engine is under load. High-performance and modified engines require higher fuel pressures to support elevated horsepower and fuel requirements.
For example, a normally aspirated engine would call for around 43 PSI, while the turbocharged or supercharged ones would need upwards of 60 PSI to maintain required fuel flow. The greater the pressure applied, the more fuel is supplied in one cycle of the injector-something very important for engines producing upwards of 400 horsepower. Therefore, in so many instances, performance enthusiasts doing upgrades on their engines find an increase in fuel pressure that can be advantageous to unlocking power.
In 2018, General Motors began production on a line of high-pressure fuel pumps for their direct-injection systems, which were capable of delivering fuel in excess of 2,000 PSI. Fuel atomization is greatly improved with these high-pressure systems, allowing more efficient combustion and increased power. This extreme level of pressure will not be needed or required by the average car engine with just a standard fuel injection system.
Another thing worth mentioning here is that the fuel pressure should complement the flow rate of the Fuel Pump. For instance, a high-flow Fuel Pump, such as a Walbro 450 LPH, can easily support 700 horsepower provided it has a properly tuned fuel pressure regulator to maintain the correct PSI. If the pressure is too low, then the engine could run lean, which may result in knocking and overheating of the engine. Vice versa, excessive pressure can cause the running of the engine rich – reducing efficiency and probably leading to fuel flooding.
As David Vizard, a very highly respected engine builder, once said, “Getting fuel pressure right is critical to engine performance—it’s all about balancing flow and pressure.” The bottom line: having your fuel pressure within the correct range for the power output of your engine will result in superior performance, better fuel economy, and longer engine life.
For more detailed information on how to setup your Fuel Pump and fuel pressure regulator, please go to Fuel Pump.