{"product_id":"spool-fx400x-hpfp-b58-gen2","title":"Spool Performance FX-400X High-Pressure Fuel Pump (Stage 4) — B58 Gen2 (G-Chassis)","description":"\u003cp\u003e\u003cstrong\u003eSpool Performance FX-400X — the flagship \"Stage 4\" high-pressure fuel pump for the Gen2 B58.\u003c\/strong\u003e It runs the same 350 bar (5,000 psi) as the FX-350 but moves about 20% more fuel across the whole delivery range, for builds that have outgrown the FX-350.\u003c\/p\u003e\n\u003ch3\u003eWhat it supports\u003c\/h3\u003e\n\u003cp\u003eWith Spool's Gen2 DI injectors, roughly 1,100 whp on gas, 900 on E50, 800 on E85; add the high-lift exhaust-cam fuel-lobe mod and about 1,200\/1,050\/900. Single pump, plug-and-play, lifetime warranty.\u003c\/p\u003e\n\u003ch3\u003eWhere it fits in the build\u003c\/h3\u003e\n\u003cp\u003eHigh-pressure (DI) side; requires an upgraded low-pressure in-tank pump and a matching calibration. We tune the engine to the fuel system.\u003c\/p\u003e\n\u003ch3\u003eOptions\u003c\/h3\u003e\n\u003cp\u003eSpool offers a wireless ethanol-content analyzer and a 10-micron inline filter as add-ons — tell us if you want either specced in.\u003c\/p\u003e\n\u003ch3\u003eFitment\u003c\/h3\u003e\n\u003cp\u003eGen2 B58 (G-chassis) — M340i (G20\/G21), M440i (G22\/G23\/G26), M240i (G42), Z4 M40i (G29), and the rest of the Gen2 B58 range. Confirm your chassis in the selector.\u003c\/p\u003e\n\u003cp\u003eSourcing fueling with the tune? The \u003ca href=\"\/products\/fueling-kit-b58\"\u003eFueling Kit — B58\u003c\/a\u003e bundles the matched pump + calibration for 8% under à la carte.\u003c\/p\u003e","brand":"Spool Performance","offers":[{"title":"None \/ None","offer_id":43280695492669,"sku":"SP-FX400X-NENF-6D","price":3035.0,"currency_code":"USD","in_stock":true},{"title":"Use my existing \/ None","offer_id":43280695525437,"sku":"SP-FX400X-NENF-6D-UE","price":3035.0,"currency_code":"USD","in_stock":true},{"title":"Include \/ None","offer_id":43280695558205,"sku":"SP-FX400X-NENF-6D-EA","price":3384.0,"currency_code":"USD","in_stock":true},{"title":"None \/ With 10-Micron Filter","offer_id":43280695590973,"sku":"SP-FX400X-NENF-6D-F","price":3184.0,"currency_code":"USD","in_stock":true},{"title":"Use my existing \/ With 10-Micron Filter","offer_id":43280695623741,"sku":"SP-FX400X-NENF-6D-UE-F","price":3184.0,"currency_code":"USD","in_stock":true},{"title":"Include \/ With 10-Micron Filter","offer_id":43280695656509,"sku":"SP-FX400X-NENF-6D-EA-F","price":3533.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0658\/2553\/8109\/files\/spool_fx-400x_b58_g2_ew.webp?v=1781742886","url":"https:\/\/essewerks.com\/products\/spool-fx400x-hpfp-b58-gen2","provider":"Esse Werks","version":"1.0","type":"link"}