{"product_id":"bmw-s58-auxiliary-split-fuel-system","title":"BMW S58 Auxiliary Split Fuel System","description":"\u003cp data-start=\"213\" data-end=\"446\"\u003eThe \u003cstrong data-start=\"217\" data-end=\"264\"\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-start=\"448\" data-end=\"688\"\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-start=\"690\" data-end=\"742\"\u003eWhy a Properly Split DI + PI Fuel System Matters\u003c\/h3\u003e\n\u003cp data-start=\"744\" data-end=\"913\"\u003eAs power levels increase on the S58 platform, fueling challenges typically come from \u003cstrong data-start=\"829\" data-end=\"912\"\u003esupplying direct injection (DI) and port injection (PI) from the same fuel feed\u003c\/strong\u003e.\u003c\/p\u003e\n\u003cp data-start=\"915\" data-end=\"943\"\u003eWhen DI and PI share a feed:\u003c\/p\u003e\n\u003cul data-start=\"945\" data-end=\"1265\"\u003e\n\u003cli data-start=\"945\" data-end=\"1051\"\u003e\n\u003cp data-start=\"947\" data-end=\"1051\"\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-start=\"1052\" data-end=\"1166\"\u003e\n\u003cp data-start=\"1054\" data-end=\"1166\"\u003ePort injection requires boost-referenced fuel pressure to maintain consistent injector differential under load\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"1167\" data-end=\"1265\"\u003e\n\u003cp data-start=\"1169\" data-end=\"1265\"\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-start=\"1267\" data-end=\"1469\"\u003eBy separating the DI and PI supply, each system operates independently and exactly as intended. The result is \u003cstrong data-start=\"1377\" data-end=\"1468\"\u003esmoother fuel delivery, improved consistency, and greater confidence as power increases\u003c\/strong\u003e.\u003c\/p\u003e\n\u003ch3 data-start=\"1471\" data-end=\"1502\"\u003eDesigned to Install Cleanly\u003c\/h3\u003e\n\u003cp data-start=\"1504\" data-end=\"1635\"\u003eA significant amount of development time went into making this system straightforward to install without unnecessary modifications.\u003c\/p\u003e\n\u003cul data-start=\"1637\" data-end=\"2079\"\u003e\n\u003cli data-start=\"1637\" data-end=\"1854\"\u003e\n\u003cp data-start=\"1639\" data-end=\"1854\"\u003e\u003cstrong data-start=\"1639\" data-end=\"1788\"\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-start=\"1855\" data-end=\"1938\"\u003e\n\u003cp data-start=\"1857\" data-end=\"1938\"\u003e\u003cstrong data-start=\"1857\" data-end=\"1910\"\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-start=\"1939\" data-end=\"2079\"\u003e\n\u003cp data-start=\"1941\" data-end=\"2079\"\u003e\u003cstrong data-start=\"1941\" data-end=\"2039\"\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-start=\"2081\" data-end=\"2188\"\u003eThese design choices keep the install clean, reduce complexity, and maintain a factory-like fit and finish.\u003c\/p\u003e\n\u003ch3 data-start=\"2190\" data-end=\"2227\"\u003eScalable Pump and Control Options\u003c\/h3\u003e\n\u003cp data-start=\"2229\" data-end=\"2273\"\u003eThe system is built to grow with your setup:\u003c\/p\u003e\n\u003cul data-start=\"2275\" data-end=\"2507\"\u003e\n\u003cli data-start=\"2275\" data-end=\"2325\"\u003e\n\u003cp data-start=\"2277\" data-end=\"2325\"\u003e\u003cstrong data-start=\"2277\" data-end=\"2325\"\u003eDual Walbro 450 fuel pumps included standard\u003c\/strong\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"2326\" data-end=\"2398\"\u003e\n\u003cp data-start=\"2328\" data-end=\"2398\"\u003e\u003cstrong data-start=\"2328\" data-end=\"2360\"\u003eOptional Walbro 525 upgrades\u003c\/strong\u003e available for higher horsepower goals\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"2399\" data-end=\"2507\"\u003e\n\u003cp data-start=\"2401\" data-end=\"2411\"\u003eChoice of:\u003c\/p\u003e\n\u003cul data-start=\"2414\" data-end=\"2507\"\u003e\n\u003cli data-start=\"2414\" data-end=\"2446\"\u003e\n\u003cp data-start=\"2416\" data-end=\"2446\"\u003eStandard relay configuration\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"2449\" data-end=\"2507\"\u003e\n\u003cp data-start=\"2451\" data-end=\"2507\"\u003e\u003cstrong data-start=\"2451\" data-end=\"2479\"\u003eSolid-state relay option\u003c\/strong\u003e for full PWM pump control\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp data-start=\"2509\" data-end=\"2613\"\u003eThis flexibility allows you to match the fuel system to your current build while leaving room to expand.\u003c\/p\u003e\n\u003ch3 data-start=\"2615\" data-end=\"2645\"\u003eHigh-Quality Fuel Plumbing\u003c\/h3\u003e\n\u003cp data-start=\"2647\" data-end=\"2725\"\u003eAll fuel lines included in the kit feature \u003cstrong data-start=\"2690\" data-end=\"2724\"\u003etriple-layer PTFE construction\u003c\/strong\u003e:\u003c\/p\u003e\n\u003cul data-start=\"2727\" data-end=\"2933\"\u003e\n\u003cli data-start=\"2727\" data-end=\"2790\"\u003e\n\u003cp data-start=\"2729\" data-end=\"2790\"\u003eInner \u003cstrong data-start=\"2735\" data-end=\"2748\"\u003ePTFE core\u003c\/strong\u003e for full fuel and ethanol compatibility\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"2791\" data-end=\"2857\"\u003e\n\u003cp data-start=\"2793\" data-end=\"2857\"\u003eMiddle \u003cstrong data-start=\"2800\" data-end=\"2833\"\u003estainless steel reinforcement\u003c\/strong\u003e for pressure strength\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"2858\" data-end=\"2933\"\u003e\n\u003cp data-start=\"2860\" data-end=\"2933\"\u003eOuter \u003cstrong data-start=\"2866\" data-end=\"2892\"\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-start=\"2935\" data-end=\"3012\"\u003eThis ensures long-term reliability in high-heat, high-vibration environments.\u003c\/p\u003e\n\u003ch3 data-start=\"3014\" data-end=\"3065\"\u003eCompact, Purpose-Built Fuel Pressure Regulation\u003c\/h3\u003e\n\u003cp data-start=\"3067\" data-end=\"3217\"\u003eThe system includes Spool Performance’s \u003cstrong data-start=\"3107\" data-end=\"3160\"\u003ein-house designed compact fuel pressure regulator\u003c\/strong\u003e, developed specifically for auxiliary fuel applications:\u003c\/p\u003e\n\u003cul data-start=\"3219\" data-end=\"3415\"\u003e\n\u003cli data-start=\"3219\" data-end=\"3280\"\u003e\n\u003cp data-start=\"3221\" data-end=\"3280\"\u003eBoost-referenced for accurate pressure control under load\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"3281\" data-end=\"3321\"\u003e\n\u003cp data-start=\"3283\" data-end=\"3321\"\u003eStable regulation at high flow rates\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"3322\" data-end=\"3371\"\u003e\n\u003cp data-start=\"3324\" data-end=\"3371\"\u003eCompact design for clean engine bay packaging\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"3372\" data-end=\"3415\"\u003e\n\u003cp data-start=\"3374\" data-end=\"3415\"\u003eBuilt to withstand demanding conditions\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3 data-start=\"3417\" data-end=\"3456\"\u003eBuilt to Support Serious S58 Builds\u003c\/h3\u003e\n\u003cp data-start=\"3458\" data-end=\"3674\"\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-start=\"3676\" data-end=\"3916\"\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-start=\"3918\" data-end=\"4088\"\u003e\u003cstrong data-start=\"3918\" data-end=\"4088\"\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-start=\"3918\" data-end=\"4088\"\u003e \u003c\/p\u003e\n\u003ch3 data-start=\"4115\" data-end=\"4130\"\u003e\u003cstrong data-start=\"4119\" data-end=\"4130\"\u003eFitment\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp data-start=\"4132\" data-end=\"4232\"\u003eThis auxiliary fuel system is designed for BMW vehicles equipped with the \u003cstrong data-start=\"4206\" data-end=\"4220\"\u003eS58 engine\u003c\/strong\u003e, including:\u003c\/p\u003e\n\u003cul data-start=\"4234\" data-end=\"4433\"\u003e\n\u003cli data-start=\"4234\" data-end=\"4262\"\u003e\n\u003cp data-start=\"4236\" data-end=\"4262\"\u003e\u003cstrong data-start=\"4236\" data-end=\"4252\"\u003eBMW M3 (G80)\u003c\/strong\u003e – 2021+\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"4263\" data-end=\"4299\"\u003e\n\u003cp data-start=\"4265\" data-end=\"4299\"\u003e\u003cstrong data-start=\"4265\" data-end=\"4289\"\u003eBMW M3 Touring (G81)\u003c\/strong\u003e – 2023+\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"4300\" data-end=\"4334\"\u003e\n\u003cp data-start=\"4302\" data-end=\"4334\"\u003e\u003cstrong data-start=\"4302\" data-end=\"4324\"\u003eBMW M4 (G82 \/ G83)\u003c\/strong\u003e – 2021+\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"4335\" data-end=\"4363\"\u003e\n\u003cp data-start=\"4337\" data-end=\"4363\"\u003e\u003cstrong data-start=\"4337\" data-end=\"4353\"\u003eBMW M2 (G87)\u003c\/strong\u003e – 2023+\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"4364\" data-end=\"4398\"\u003e\n\u003cp data-start=\"4366\" data-end=\"4398\"\u003e\u003cstrong data-start=\"4366\" data-end=\"4384\"\u003eBMW X3 M (F97)\u003c\/strong\u003e – 2020–2024\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"4399\" data-end=\"4433\"\u003e\n\u003cp data-start=\"4401\" data-end=\"4433\"\u003e\u003cstrong data-start=\"4401\" data-end=\"4419\"\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":53441146192166,"sku":"SP-S58AUXF450","price":1299.0,"currency_code":"USD","in_stock":true},{"title":"Walbro 525 with check valves","offer_id":53441146224934,"sku":"SP-S58AUXF525","price":1599.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0886\/1787\/7798\/files\/1_ebebb647-772f-41ae-a53d-304a5c741f8c.png?v=1783384172","url":"https:\/\/www.clubsportspec.com\/products\/bmw-s58-auxiliary-split-fuel-system","provider":"Clubsport Spec","version":"1.0","type":"link"}