{"product_id":"bmw-x3m-x4m-s58-spool-auxiliary-split-fuel-system","title":"BMW X3M \u0026 X4M S58 Spool Auxiliary Split Fuel System","description":"\u003cp\u003eThe Spool auxiliary split fuel system separates the direct injection and port injection supply so each one gets stable fuel as power climbs.\u003c\/p\u003e\u003ch2\u003eWhy you need it\u003c\/h2\u003e\u003cp\u003eWhen direct and port injection share one feed, the pulsing of the DI pump can disturb flow to the port injectors, and the port side needs boost-referenced pressure to stay consistent under load. Splitting the two systems lets each run exactly as intended for smoother, more repeatable fueling at high boost. The factory pump top hat is kept using machined aluminum fittings, so no repinning or factory wiring changes are needed.\u003c\/p\u003e\u003ch2\u003eFits\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eBMW F97 X3 M (S58)\u003c\/li\u003e\n\u003cli\u003eBMW F98 X4 M (S58)\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eWhat's included\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eDual Walbro 450 or Walbro 525 fuel pumps with check valves (selected at checkout)\u003c\/li\u003e\n\u003cli\u003ePrecision-machined aluminum fittings for the factory top hat\u003c\/li\u003e\n\u003cli\u003ePlug-and-play wiring harness for the Reflex controller\u003c\/li\u003e\n\u003cli\u003eTriple-layer fuel lines: PTFE core, stainless reinforcement, nylon outer layer\u003c\/li\u003e\n\u003cli\u003eRadium Engineering boost-referenced fuel pressure regulator\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eGood to know\u003c\/h2\u003e\u003cp\u003eThe Walbro 450 pumps suit most builds; the 525 option is for higher power goals. For full PWM pump control, two Spool PWM activation harnesses are needed and are sold separately. A supporting tune is required. Professional installation is recommended.\u003c\/p\u003e","brand":"Spool Performance","offers":[{"title":"Walbro 450 with check valves","offer_id":46564602478677,"sku":"SP-A9XAUXF450","price":1499.99,"currency_code":"USD","in_stock":true},{"title":"Walbro 525 with check valves","offer_id":46564602511445,"sku":"SP-A9XAUXF525","price":1799.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0638\/9769\/8389\/files\/7_73e9370c-fe03-4b55-a78e-6424cea0c565.png?v=1793251076","url":"https:\/\/www.wrenchhaususa.com\/products\/bmw-x3m-x4m-s58-spool-auxiliary-split-fuel-system","provider":"Wrench Haus","version":"1.0","type":"link"}