Aeromotive ReturnX Return-Type Pulse Width Modulation Controller for 3-4 Fuel Pumps - Supercharged

High-horsepower fuel pumps generate significant heat, and when combined with engine heat returned to the tank in a return-style system, the fuel tank can become a genuine thermal battery — hot enough on a warm day that it's uncomfortable to touch. The hotter the fuel gets, the more prone it becomes to vapor lock, a condition where fuel boils somewhere in the system (anywhere from the pump inlet to the rails or carb bowl) and delivery effectively stops.

High-output pumps like TI Automotive's 450lph ("Hellcat") and 525lph ("Demon") pumps can draw over 22 amps at full power, so Mopar controls them using Pulse Width Modulation (PWM) — rapidly cycling the pump on and off thousands of times per second, with pulse length determining pump speed. That speed is adjusted using feedback like engine RPM, MAP, or TPS, giving the system a way to throttle pump output based on actual demand rather than running full-blast constantly, similar to how an engine doesn't need to run at redline just because it's capable of it. The FourX system consists of a primary and secondary PWM controller output. Under normal idle/cruise driving, the #1 and #2 pumps are on the primary side and running fast enough to provide sufficient fuel pressure. Even with both pumps running a near 30% reduction in power vs. a single full-speed pump is achieved. The #3 and #4 pumps are attached to the PWM secondary output but follow at a much lower duty cycle than the primary side. As the primary side increases in output power, so does the secondary side in a leader-follower arrangement. Since all pumps are connected through the PWM controller, they will ramp together in a smooth manner without the need for relays, Hobb’s switches, and other similar
devices.

The MAP sensor provided is a 2.5bar LSA/LS9 type. This sensor has shown to have more than adequate range for all supercharged applications. Aeromotive offers EFI pressure regulators, filters, and hoses with sufficient flowrate and pressure capacity to work well with any system. Be sure to size your fuel lines accordingly. AN8 minimum for up to 1200hp. AN10 for 1200hp. It is recommended that for supercharged applications that manifold referenced fuel pressure be used with the fuel pressure set to approximately 43psi at idle. This will reduce the load on the fuel pump(s) and the vehicle electrical system.

Note: A return/bypass-style fuel pressure regulator is required for this setup