Spool Auxiliary Split Fuel System - Gen 2 B58 BMW

Spool Performance B58 Gen 2 Auxiliary Fuel System The Spool Performance B58 Gen 2 Auxiliary Fuel System is designed for B58 Gen 2 owners pushing beyond the limits of the factory fuel system who want a solution that’s properly engineered, easy to install, and built for long-term reliability. From the start, our focus was on correct fuel architecture and real-world usability. Every component and layout choice was made to deliver stable, predictable fueling at higher power levels while keeping installation clean and OEM-friendly. Why a Properly Designed DI + PI Fuel System Matters As power levels increase on the B58 Gen 2 platform, fueling challenges typically arise when direct injection (DI) and port injection (PI) are supplied from the same fuel feed .

Fits: Gen 2 B58 BMW G-series: M340i (G20), M440i (G22), M240i (G42), Z4 M40i (G29), 540i, 740i and X3 M40i (2020+)

Brand: Spool Performance

• Ships from the brand or distributor, usually in 3–7 business days.
• Shipping is charged at the carrier's rate, shown at checkout. Orders over 70 lb ship by freight for a flat $99.
• Unused parts can be returned within 30 days. Some items are marked no-refund in their description.

Full details are on our shipping and returns page.