SPOOL F-Series S55 High Performance Fuel Pump - Stage 3 & Stage 4 - 900WHP+

The Spool Performance F-Series S55 High-Performance Fuel Pump Kits are designed to provide the increased fuel supply required by high-powered BMW S55 builds. Available in Stage 3 and Stage 4 configurations, these fuel pump systems are designed to support applications ranging from upgraded pump-gas setups to high-ethanol and full E85 builds.

Each system integrates an OEM brushless fuel pump into the factory-style fuel pump bucket along with an auxiliary pump installed inside the bucket. This configuration provides increased fuel delivery while maintaining a clean, factory-style installation.

The kits include the OEM fuel pump bucket assembly, fuel level sending unit, plug-and-play wiring, and auxiliary pump activation hardware. The auxiliary pump can be activated using the included 10 psi Hobbs switch, or customers can choose a ReFlex ground activation harness where applicable. The plug-and-play design eliminates the need for cutting, splicing, or crimping factory wiring.

Stage 3 – Up to 900 WHP

The Stage 3 fuel pump system is designed for S55 applications requiring additional fuel delivery for increased boost and higher ethanol content. This configuration combines the OEM brushless pump with an in-bucket DW420 auxiliary pump, providing an easy-install solution without an external pump bracket.

Stage 3 Power Support

• Up to 900 WHP
• Up to 850 WHP on full E85

Stage 3 Includes

• Genuine OEM fuel pump bucket assembly
• OEM brushless fuel pump
• DW420 auxiliary pump installed inside the bucket
• Fuel level sending unit
• Plug-and-play boost activation harness
• 10 psi Hobbs switch
• ReFlex activation option available upon request

Stage 4 – Return-Style Fuel System / AFS – Up to 1,000 WHP

The Stage 4 system expands on the high-flow dual-pump configuration with upgraded fuel plumbing and a regulated return-style fuel system. It combines the OEM brushless pump with an in-bucket DW420 auxiliary pump, along with upgraded fuel lines, filtration, and fuel pressure regulation.

Stage 4 Power Support

• Up to 1,000 WHP
• Up to 950 WHP on full E85

Stage 4 Includes

• Genuine OEM fuel pump bucket assembly
• OEM brushless fuel pump
• DW420 auxiliary pump installed inside the bucket
• Fuel level sending unit
• Upgraded -6 AN fuel feed and return lines
• Genuine Radium Engineering 1:1 compact fuel pressure regulator
• New inline fuel filter
• ReFlex activation harness

Key Features

• Designed for BMW S55 high-performance applications
• Stage 3 and Stage 4 configurations available
• OEM brushless pump with in-bucket auxiliary pump
• DW420 auxiliary pump
• Supports high-power pump-gas and ethanol applications
• E85-compatible components
• Plug-and-play wiring
• No cutting, splicing, or crimping required
• Factory-style fuel pump bucket integration
• Fuel level sending unit included
• No core charge
• Stage 4 includes return-style fuel system and upgraded -6 AN plumbing

Important: Power ratings are estimates and can vary depending on fuel blend, operating fuel pressure, electrical supply, tuning, and the rest of the vehicle's fuel system.