{"product_id":"bmw-b58-gen2-auxiliary-split-fuel-system","title":"BMW B58 Gen2 Auxiliary Split Fuel System","description":"\u003ch2\u003eSpool Performance B58 Gen 2 Auxiliary Fuel System\u003c\/h2\u003e\n\u003cp\u003eThe \u003cstrong\u003eSpool Performance B58 Gen 2 Auxiliary Fuel System\u003c\/strong\u003e 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.\u003c\/p\u003e\n\u003cp\u003eFrom 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.\u003c\/p\u003e\n\u003ch3\u003eWhy a Properly Designed DI + PI Fuel System Matters\u003c\/h3\u003e\n\u003cp\u003eAs power levels increase on the B58 Gen 2 platform, fueling challenges typically arise when \u003cstrong\u003edirect injection (DI) and port injection (PI) are supplied from the same fuel feed\u003c\/strong\u003e.\u003c\/p\u003e\n\u003cp\u003eWhen DI and PI share a feed:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003eThe pulsed nature of DI can introduce pressure fluctuations that disrupt fuel flow to the PI injectors\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003ePort injection requires boost-referenced fuel pressure to maintain consistent injector differential under load\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eAt higher boost and airflow, maintaining precise and repeatable fueling becomes more difficult\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eBy separating the DI and PI supply, each system is able to operate independently and exactly as intended. The result is \u003cstrong\u003esmoother fuel delivery, improved consistency, and greater confidence as power increases\u003c\/strong\u003e.\u003c\/p\u003e\n\u003ch3\u003eDesigned to Install Cleanly\u003c\/h3\u003e\n\u003cp\u003eA significant amount of development time went into making this system straightforward to install without unnecessary modifications.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eThe OEM fuel pump top hat is retained using additional precision-machined aluminum fuel fittings that integrate directly into the factory top hat\u003c\/strong\u003e, eliminating the need for repinning or modifying factory wiring\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eA plug-and-play wiring harness is supplied for direct compatibility with the Reflex controller\u003c\/strong\u003e, simplifying installation and control\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eThese design choices keep the install clean, reduce complexity, and maintain a factory-like fit and finish.\u003c\/p\u003e\n\u003ch3\u003eScalable Pump and Control Options\u003c\/h3\u003e\n\u003cp\u003eThe system is built to grow with your setup:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eDual Walbro 450 fuel pumps included standard\u003c\/strong\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eOptional Walbro 525 upgrades\u003c\/strong\u003e available for higher horsepower goals\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eChoice of:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003eStandard relay configuration\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eSolid-state relay option\u003c\/strong\u003e for full PWM pump control available for purchase separately. NOTE: 2 harnesses required per AFS Kit - Link to Harness: https:\/\/spoolperformance.com\/products\/spool-lpfp-pwm-activation-harness-bmw?_pos=1\u0026amp;_sid=2a7c2a7b8\u0026amp;_ss=r\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eThis flexibility allows you to match the fuel system to your current build while leaving room to expand.\u003c\/p\u003e\n\u003ch3\u003eHigh-Quality Fuel Plumbing\u003c\/h3\u003e\n\u003cp\u003eAll fuel lines included in the kit feature \u003cstrong\u003etriple-layer PTFE construction\u003c\/strong\u003e:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003eInner \u003cstrong\u003ePTFE core\u003c\/strong\u003e for full fuel and ethanol compatibility\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eMiddle \u003cstrong\u003estainless steel reinforcement\u003c\/strong\u003e for pressure strength\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eOuter \u003cstrong\u003enylon protective layer\u003c\/strong\u003e for abrasion resistance and durability\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eThis ensures long-term reliability in high-heat, high-vibration environments.\u003c\/p\u003e\n\u003ch3\u003eCompact, Purpose-Built Fuel Pressure Regulation\u003c\/h3\u003e\n\u003cp\u003eThe system includes Radium Engineering's FPR.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003eBoost-referenced for accurate pressure control under load\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eStable regulation at high flow rates\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eCompact design for clean engine bay packaging\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eBuilt to withstand demanding conditions\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eBuilt to Support Serious B58 Gen 2 Builds\u003c\/h3\u003e\n\u003cp\u003eWhether you’re building a strong street car or planning a higher-power setup, the Spool Performance B58 Gen 2 Auxiliary Fuel System delivers the fueling control and capacity needed to push the platform with confidence.\u003c\/p\u003e\n\u003cp\u003eWith properly separated DI and PI supply, OEM-friendly integration using precision aluminum fittings, Reflex compatibility, high-quality plumbing, and scalable pump options, this system is designed to perform reliably as your build evolves.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eIf you’re ready to upgrade your B58 Gen 2 fueling with a system that’s thoughtfully engineered and genuinely easy to live with, this is the solution built to get you there.\u003c\/strong\u003e\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003e\u003cstrong\u003eFitment\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThis auxiliary fuel system is designed for BMW vehicles equipped with the \u003cstrong\u003eB58 Gen 2 engine\u003c\/strong\u003e, including:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan class=\"hover:entity-accent entity-underline inline cursor-pointer align-baseline\"\u003e\u003cspan class=\"whitespace-normal\"\u003eBMW M340i\u003c\/span\u003e\u003c\/span\u003e \/ \u003cspan class=\"hover:entity-accent entity-underline inline cursor-pointer align-baseline\"\u003e\u003cspan class=\"whitespace-normal\"\u003eBMW M340i xDrive\u003c\/span\u003e\u003c\/span\u003e\u003c\/strong\u003e – 2020+\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan class=\"hover:entity-accent entity-underline inline cursor-pointer align-baseline\"\u003e\u003cspan class=\"whitespace-normal\"\u003eBMW M440i\u003c\/span\u003e\u003c\/span\u003e \/ \u003cspan class=\"hover:entity-accent entity-underline inline cursor-pointer align-baseline\"\u003e\u003cspan class=\"whitespace-normal\"\u003eBMW M440i xDrive\u003c\/span\u003e\u003c\/span\u003e\u003c\/strong\u003e – 2021+\u003cstrong\u003e\u003cspan class=\"hover:entity-accent entity-underline inline cursor-pointer align-baseline\"\u003e\u003cspan class=\"whitespace-normal\"\u003e\u003c\/span\u003e\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan class=\"hover:entity-accent entity-underline inline cursor-pointer align-baseline\"\u003e\u003cspan class=\"whitespace-normal\"\u003eBMW X3 M40i\u003c\/span\u003e\u003c\/span\u003e\u003c\/strong\u003e – 2020+\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan class=\"hover:entity-accent entity-underline inline cursor-pointer align-baseline\"\u003e\u003cspan class=\"whitespace-normal\"\u003eBMW X4 M40i\u003c\/span\u003e\u003c\/span\u003e\u003c\/strong\u003e – 2020+\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Spool Performance","offers":[{"title":"Walbro 450 with check valves","offer_id":50416492413185,"sku":"SP-B58G2AUXF450","price":1299.0,"currency_code":"USD","in_stock":true},{"title":"Walbro 525 with check valves","offer_id":50416492445953,"sku":"SP-B58G2AUXF525","price":1599.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0842\/4610\/2273\/files\/1_e38a945a-693e-46c8-bb51-98c91f42313e.png?v=1790644704","url":"https:\/\/fphpro.com\/products\/bmw-b58-gen2-auxiliary-split-fuel-system","provider":"Flako performance house","version":"1.0","type":"link"}