Spool BMW S58 Auxiliary Split Fuel System for Port Injection

Complete auxiliary fuel system that separates the S58 direct-injection and port-injection fuel supplies for more stable, boost-referenced fueling at higher power levels.

• Independent direct-injection and port-injection fuel feeds
• Retains the OEM fuel-pump top hat using precision-machined adapter fittings
• Plug-and-play harness compatibility with the MOTIV ReFlex controller
• Dual Walbro 450 pumps supplied as standard
• Optional dual Walbro 525 configuration for higher fuel demand
• Triple-layer PTFE fuel plumbing with stainless reinforcement and nylon protection
• Compact boost-referenced fuel-pressure regulator
• OEM-friendly engine-bay and fuel-tank packaging

Important: Solid-state PWM relay harnesses are separate options. Confirm pump choice, port-injection controller, injector size and base fuel pressure with the tuner before installation.

Confirmed catalogue fitment

• Engine families: S58
• BMW chassis: F97, F98, G80, G81, G82, G83, G87
• Vehicle models: M2, M3, M3 Touring, M4, X3 M, X4 M
• Production years: 2020-2024, 2020-2025, 2021-2026, 2023-2026
• Drivetrain: AWD, RWD

Fuel-system selection and installation

Fuel-system parts must be selected around the complete combination of engine generation, fuel type, target output, existing pump and injector configuration, and the calibration strategy. A component appearing for an engine family does not mean it replaces every factory or upgraded fuel-system arrangement used on that engine.

Professional installation and calibration are recommended where the product changes fuel pressure, pump control, injector flow, ethanol-content input or port-injection operation. Confirm wiring, plumbing, electrical load, controller requirements and compatible supporting hardware before ordering.

Before ordering

Select your exact BMW through MLAB My Garage and review the product options, included parts and installation requirements. Where a vehicle has been modified from its original engine, transmission or fuel-system specification, contact MLAB with the VIN and current hardware list so the combination can be checked before supply.

MLAB support

MLAB by Boost and Tune can assist with product selection, workshop installation and dyno calibration for supported BMW applications in Melbourne. Product availability and lead time should be confirmed when ordering supplier-built or special-order components.