Stage 3 Low Pressure Fuel Pump

The Spool Performance Stage 3 Low Pressure Fuel Pump is a direct-fit, twin-pump in-tank upgrade for the S55 engine, designed to address fueling limitations in high-horsepower builds. The factory low-pressure pump can become a bottleneck, especially when using fuels like E85 or under high boost conditions, leading to a drop in rail pressure. This Stage 3 LPFP system introduces a secondary pump that activates only under boost, significantly increasing fuel flow while maintaining quiet operation during normal cruising. This kit is engineered to provide approximately double the flow of a stock pump and is capable of supporting over 1200 wheel horsepower, ensuring adequate fuel supply for aggressive engine calibrations. It is a complete drop-in replacement, requiring no additional assembly or core returns. The design ensures that the high-pressure fuel pump (HPFP) is never starved, which is critical for maintaining consistent fuel pressure required by high-output tunes. Specifically designed for the S55 engine, this fuel pump is compatible with the F80 M3, F82/F83 M4, and F87 M2 Competition chassis. It functions as the low-pressure side of the fuel system and is intended to be paired with an upgraded high-pressure (Direct Injection) pump to create a comprehensive fueling solution. The product is noted as being "Assembled" and is available for purchase directly from Spool Performance or through authorized dealers. While the product page does not explicitly mention tuning requirements, high-performance fuel system upgrades typically necessitate engine recalibration by a professional tuner to optimize performance and ensure safety.