{"product_id":"bmw-s58-auxiliary-split-fuel-system","title":"Spool Performance Auxiliary Split Fuel System BMW S58","description":"\u003cp data-end=\"446\" data-start=\"213\"\u003eThe \u003cstrong data-end=\"264\" data-start=\"217\"\u003eSpool Performance S58 Auxiliary Fuel System\u003c\/strong\u003e is designed for S58 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 data-end=\"688\" data-start=\"448\"\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 data-end=\"742\" data-start=\"690\"\u003eWhy a Properly Split DI + PI Fuel System Matters\u003c\/h3\u003e\n\u003cp data-end=\"913\" data-start=\"744\"\u003eAs power levels increase on the S58 platform, fueling challenges typically come from \u003cstrong data-end=\"912\" data-start=\"829\"\u003esupplying direct injection (DI) and port injection (PI) from the same fuel feed\u003c\/strong\u003e.\u003c\/p\u003e\n\u003cp data-end=\"943\" data-start=\"915\"\u003eWhen DI and PI share a feed:\u003c\/p\u003e\n\u003cul data-end=\"1265\" data-start=\"945\"\u003e\n\u003cli data-end=\"1051\" data-start=\"945\"\u003e\n\u003cp data-end=\"1051\" data-start=\"947\"\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 data-end=\"1166\" data-start=\"1052\"\u003e\n\u003cp data-end=\"1166\" data-start=\"1054\"\u003ePort injection requires boost-referenced fuel pressure to maintain consistent injector differential under load\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-end=\"1265\" data-start=\"1167\"\u003e\n\u003cp data-end=\"1265\" data-start=\"1169\"\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 data-end=\"1469\" data-start=\"1267\"\u003eBy separating the DI and PI supply, each system operates independently and exactly as intended. The result is \u003cstrong data-end=\"1468\" data-start=\"1377\"\u003esmoother fuel delivery, improved consistency, and greater confidence as power increases\u003c\/strong\u003e.\u003c\/p\u003e\n\u003ch3 data-end=\"1502\" data-start=\"1471\"\u003eDesigned to Install Cleanly\u003c\/h3\u003e\n\u003cp data-end=\"1635\" data-start=\"1504\"\u003eA significant amount of development time went into making this system straightforward to install without unnecessary modifications.\u003c\/p\u003e\n\u003cul data-end=\"2079\" data-start=\"1637\"\u003e\n\u003cli data-end=\"1854\" data-start=\"1637\"\u003e\n\u003cp data-end=\"1854\" data-start=\"1639\"\u003e\u003cstrong data-end=\"1788\" data-start=\"1639\"\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 data-end=\"1938\" data-start=\"1855\"\u003e\n\u003cp data-end=\"1938\" data-start=\"1857\"\u003e\u003cstrong data-end=\"1910\" data-start=\"1857\"\u003eOptional billet top hats are available separately\u003c\/strong\u003e for those who prefer them\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-end=\"2079\" data-start=\"1939\"\u003e\n\u003cp data-end=\"2079\" data-start=\"1941\"\u003e\u003cstrong data-end=\"2039\" data-start=\"1941\"\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 data-end=\"2188\" data-start=\"2081\"\u003eThese design choices keep the install clean, reduce complexity, and maintain a factory-like fit and finish.\u003c\/p\u003e\n\u003ch3 data-end=\"2227\" data-start=\"2190\"\u003eScalable Pump and Control Options\u003c\/h3\u003e\n\u003cp data-end=\"2273\" data-start=\"2229\"\u003eThe system is built to grow with your setup:\u003c\/p\u003e\n\u003cul data-end=\"2507\" data-start=\"2275\"\u003e\n\u003cli data-end=\"2325\" data-start=\"2275\"\u003e\n\u003cp data-end=\"2325\" data-start=\"2277\"\u003e\u003cstrong data-end=\"2325\" data-start=\"2277\"\u003eDual Walbro 450 fuel pumps included standard\u003c\/strong\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-end=\"2398\" data-start=\"2326\"\u003e\n\u003cp data-end=\"2398\" data-start=\"2328\"\u003e\u003cstrong data-end=\"2360\" data-start=\"2328\"\u003eOptional Walbro 525 upgrades\u003c\/strong\u003e available for higher horsepower goals\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-end=\"2507\" data-start=\"2399\"\u003e\n\u003cp data-end=\"2411\" data-start=\"2401\"\u003eChoice of:\u003c\/p\u003e\n\u003cul data-end=\"2507\" data-start=\"2414\"\u003e\n\u003cli data-end=\"2446\" data-start=\"2414\"\u003e\n\u003cp data-end=\"2446\" data-start=\"2416\"\u003eStandard relay configuration\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-end=\"2507\" data-start=\"2449\"\u003e\n\u003cp data-end=\"2507\" data-start=\"2451\"\u003e\u003cstrong data-end=\"2479\" data-start=\"2451\"\u003eSolid-state relay option\u003c\/strong\u003e for full PWM pump control \u003cmeta charset=\"utf-8\"\u003eavailable for purchase separately. NOTE: 2 harnesses required per AFS Kit - Link to Harness: https:\/\/spoolperformance.com\/products\/untitled-may18_19-53-33?_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 data-end=\"2613\" data-start=\"2509\"\u003eThis flexibility allows you to match the fuel system to your current build while leaving room to expand.\u003c\/p\u003e\n\u003ch3 data-end=\"2645\" data-start=\"2615\"\u003eHigh-Quality Fuel Plumbing\u003c\/h3\u003e\n\u003cp data-end=\"2725\" data-start=\"2647\"\u003eAll fuel lines included in the kit feature \u003cstrong data-end=\"2724\" data-start=\"2690\"\u003etriple-layer PTFE construction\u003c\/strong\u003e:\u003c\/p\u003e\n\u003cul data-end=\"2933\" data-start=\"2727\"\u003e\n\u003cli data-end=\"2790\" data-start=\"2727\"\u003e\n\u003cp data-end=\"2790\" data-start=\"2729\"\u003eInner \u003cstrong data-end=\"2748\" data-start=\"2735\"\u003ePTFE core\u003c\/strong\u003e for full fuel and ethanol compatibility\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-end=\"2857\" data-start=\"2791\"\u003e\n\u003cp data-end=\"2857\" data-start=\"2793\"\u003eMiddle \u003cstrong data-end=\"2833\" data-start=\"2800\"\u003estainless steel reinforcement\u003c\/strong\u003e for pressure strength\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-end=\"2933\" data-start=\"2858\"\u003e\n\u003cp data-end=\"2933\" data-start=\"2860\"\u003eOuter \u003cstrong data-end=\"2892\" data-start=\"2866\"\u003enylon protective layer\u003c\/strong\u003e for abrasion resistance and durability\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp data-end=\"3012\" data-start=\"2935\"\u003eThis ensures long-term reliability in high-heat, high-vibration environments.\u003c\/p\u003e\n\u003ch3 data-end=\"3065\" data-start=\"3014\"\u003eCompact, Purpose-Built Fuel Pressure Regulation\u003c\/h3\u003e\n\u003cp data-end=\"3217\" data-start=\"3067\"\u003eThe system includes Spool Performance’s \u003cstrong data-end=\"3160\" data-start=\"3107\"\u003ein-house designed compact fuel pressure regulator\u003c\/strong\u003e, developed specifically for auxiliary fuel applications:\u003c\/p\u003e\n\u003cul data-end=\"3415\" data-start=\"3219\"\u003e\n\u003cli data-end=\"3280\" data-start=\"3219\"\u003e\n\u003cp data-end=\"3280\" data-start=\"3221\"\u003eBoost-referenced for accurate pressure control under load\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-end=\"3321\" data-start=\"3281\"\u003e\n\u003cp data-end=\"3321\" data-start=\"3283\"\u003eStable regulation at high flow rates\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-end=\"3371\" data-start=\"3322\"\u003e\n\u003cp data-end=\"3371\" data-start=\"3324\"\u003eCompact design for clean engine bay packaging\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-end=\"3415\" data-start=\"3372\"\u003e\n\u003cp data-end=\"3415\" data-start=\"3374\"\u003eBuilt to withstand demanding conditions\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3 data-end=\"3456\" data-start=\"3417\"\u003eBuilt to Support Serious S58 Builds\u003c\/h3\u003e\n\u003cp data-end=\"3674\" data-start=\"3458\"\u003eWhether you’re building a strong street car or planning a higher-power setup, the Spool Performance S58 Auxiliary Fuel System delivers the fueling control and capacity needed to push the S58 platform with confidence.\u003c\/p\u003e\n\u003cp data-end=\"3916\" data-start=\"3676\"\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 data-end=\"4088\" data-start=\"3918\"\u003e\u003cstrong data-end=\"4088\" data-start=\"3918\"\u003eIf you’re ready to upgrade your S58 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\u003cp data-end=\"4088\" data-start=\"3918\"\u003e \u003c\/p\u003e\n\u003ch3 data-end=\"4130\" data-start=\"4115\"\u003e\u003cstrong data-end=\"4130\" data-start=\"4119\"\u003eFitment\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp data-end=\"4232\" data-start=\"4132\"\u003eThis auxiliary fuel system is designed for BMW vehicles equipped with the \u003cstrong data-end=\"4220\" data-start=\"4206\"\u003eS58 engine\u003c\/strong\u003e, including:\u003c\/p\u003e\n\u003cul data-end=\"4433\" data-start=\"4234\"\u003e\n\u003cli data-end=\"4262\" data-start=\"4234\"\u003e\n\u003cp data-end=\"4262\" data-start=\"4236\"\u003e\u003cstrong data-end=\"4252\" data-start=\"4236\"\u003eBMW M3 (G80)\u003c\/strong\u003e – 2021+\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-end=\"4299\" data-start=\"4263\"\u003e\n\u003cp data-end=\"4299\" data-start=\"4265\"\u003e\u003cstrong data-end=\"4289\" data-start=\"4265\"\u003eBMW M3 Touring (G81)\u003c\/strong\u003e – 2023+\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-end=\"4334\" data-start=\"4300\"\u003e\n\u003cp data-end=\"4334\" data-start=\"4302\"\u003e\u003cstrong data-end=\"4324\" data-start=\"4302\"\u003eBMW M4 (G82 \/ G83)\u003c\/strong\u003e – 2021+\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-end=\"4363\" data-start=\"4335\"\u003e\n\u003cp data-end=\"4363\" data-start=\"4337\"\u003e\u003cstrong data-end=\"4353\" data-start=\"4337\"\u003eBMW M2 (G87)\u003c\/strong\u003e – 2023+\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-end=\"4398\" data-start=\"4364\"\u003e\n\u003cp data-end=\"4398\" data-start=\"4366\"\u003e\u003cstrong data-end=\"4384\" data-start=\"4366\"\u003eBMW X3 M (F97)\u003c\/strong\u003e – 2020–2024\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-end=\"4433\" data-start=\"4399\"\u003e\n\u003cp data-end=\"4433\" data-start=\"4401\"\u003e\u003cstrong data-end=\"4419\" data-start=\"4401\"\u003eBMW X4 M (F98)\u003c\/strong\u003e – 2020–2024\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Spool Performance","offers":[{"title":"Walbro 450 with check valves","offer_id":53519896379708,"sku":"SP-S58AUXF450","price":1299.0,"currency_code":"USD","in_stock":true},{"title":"Walbro 525 with check valves","offer_id":53519896412476,"sku":"SP-S58AUXF525","price":1599.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0714\/3070\/1372\/files\/1_ebebb647-772f-41ae-a53d-304a5c741f8c.png?v=1784239678","url":"https:\/\/trucranemotorsports.com\/products\/bmw-s58-auxiliary-split-fuel-system","provider":"TruCrane Motorsports","version":"1.0","type":"link"}