Spool BMW B58 Gen 1 Auxiliary Split Fuel System

Spool BMW B58 Gen 1 Auxiliary Split Fuel System separates the direct-injection and port-injection fuel feeds for more stable, boost-referenced fueling on higher-output BMW B58 builds.

• Dual Walbro 450 pumps supplied as the base configuration
• Optional dual Walbro 525 configuration for higher fuel demand
• OEM fuel-pump top-hat integration using precision-machined fittings
• Plug-and-play ReFlex controller compatibility
• Triple-layer PTFE fuel plumbing with stainless reinforcement
• Compact boost-referenced Spool fuel-pressure regulator

Fitment: BMW B58 Gen 1: F22/F23 M240i, F30/F31/F34 340i and F32/F33/F36 440i applications listed by Spool.

Important: Spool's solid-state PWM relay harness is a separate option. Confirm pump choice, port-injection controller, injector size and base pressure with the tuner.

Dispatch: Special order — allow 3–4 weeks.

Confirmed catalogue fitment

• Engine families: B58
• BMW chassis: F22, F23, F30, F31, F34, F32, F33, F36
• Vehicle models: M240i, 340i, 440i

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.