{"product_id":"er-n55-downpipe","title":"Evolution Racewerks 4\" Downpipe — N55 (F-Chassis)","description":"\u003cp\u003e\u003cstrong\u003eEvolution Racewerks 4\" downpipe for the single-turbo N55.\u003c\/strong\u003e The N55 is the bridge engine between the older twin-turbo I6 and the modern B58. Smaller exhaust mass-flow than either, but the OEM downpipe restriction still caps Stage 2 + 3 N55 builds at peak power. ER's 4\" replacement opens that restriction completely.\u003c\/p\u003e\n\n\u003ch3\u003eN55 single-turbo math\u003c\/h3\u003e\n\u003cp\u003eThe N55 uses a single twin-scroll turbo. One downpipe to replace (not the twin setup of the S55). ER's 4\" pipe handles the N55's airflow ceiling cleanly through Stage 3 on a supporting-hardware build.\u003c\/p\u003e\n\n\u003ch3\u003eReal-world output difference\u003c\/h3\u003e\n\u003cp\u003eCommunity feedback on calibrated N55 builds consistently reports a measurable gain from the downpipe alone — the pipe removes a restriction the OEM section imposes for noise and emissions compliance, which the tune can then capitalize on.\u003c\/p\u003e\n\n\u003ch3\u003eCatless vs Catted\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eCatless:\u003c\/strong\u003e race-only, maximum flow. CEL on stock cal.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHigh-Flow Catted:\u003c\/strong\u003e 200-cell metallic catalyst. CEL-clean on stock cal.\u003c\/p\u003e\n\n\u003ch3\u003eWhat Evolution Racewerks builds in\u003c\/h3\u003e\n\u003cul\u003e\n \u003cli\u003e100% 304-grade stainless steel construction\u003c\/li\u003e\n \u003cli\u003eMandrel-bent piping — smooth transitions, no flow restrictions at the bends\u003c\/li\u003e\n \u003cli\u003e100% TIG-welded by ER's in-house fabricators\u003c\/li\u003e\n \u003cli\u003ePrecision CNC-machined flanges (billet 304 stainless)\u003c\/li\u003e\n \u003cli\u003eMade in the USA — manufactured in-house at ER's California facility\u003c\/li\u003e\n \u003cli\u003e\n\u003cstrong\u003eLimited Lifetime Warranty\u003c\/strong\u003e against manufacturing defects\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eEGT bung included — standard on every Esse Werks ER order\u003c\/h3\u003e\n\u003cp\u003eEvolution Racewerks offers the EGT (Exhaust Gas Temperature) sensor bung as an optional add-on on their direct catalog. \u003cstrong\u003eWe include it on every ER downpipe \/ mid pipe we ship — no upcharge.\u003c\/strong\u003e Comes pre-installed with a 1\/8\" NPT plug so you don't need to run the EGT sensor immediately. When you're ready to add EGT monitoring to your build (recommended at Stage 2 and above for any sustained-load driving), the bung is already there.\u003c\/p\u003e\n\n\u003ch3\u003eSwainTech White Lightning — our signature coating\u003c\/h3\u003e\n\u003cp\u003eWhen we coat a part, we use one coating: SwainTech White Lightning — a true ceramic thermal barrier applied about 0.015\" thick (versus roughly 0.002\" for paint-style \"ceramic\" finishes) and sprayed molten so it bonds to the metal instead of sitting on top. It cuts radiant heat off the exhaust by roughly 35–55%, dropping underhood and intake temperatures, and keeps heat inside the pipe where it sustains exhaust velocity and scavenging. And it's white — a deliberate signature in a market that otherwise all looks the same in black. Select it above.\u003c\/p\u003e\n\n\u003ch3\u003eCalifornia restriction\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eThis product is not for sale, installation, or use on licensed vehicles in the State of California.\u003c\/strong\u003e 49-state product. Vehicle Compliance Waiver signed at order intake. International orders ship without restriction.\u003c\/p\u003e\n\n\u003ch3\u003eInstall\u003c\/h3\u003e\n\u003cp\u003e~3-4 hours at a competent shop. Reuses OEM hardware where applicable. Includes all hardware for complete installation.\u003c\/p\u003e\n\n\u003ch3\u003eFitment\u003c\/h3\u003e\n\u003cp\u003eAll N55 BMW applications — F20\/F21 M135i, F22\/F23 M235i (2014-2016 N55), F30 335i (2012-2015), F31 335i Touring, F32 435i (2014-2016), F33 435i, F36 435i, F87 M2 (2016-2018 pre-Competition).\u003c\/p\u003e\n\u003cp\u003eThis part is the downpipe-side Core of every N55 Stage 2 build. The \u003ca href=\"\/products\/stage-2-kit-n55\"\u003eStage 2 Kit — N55\u003c\/a\u003e packages the matched parts + calibration for 8% under à la carte.\u003c\/p\u003e","brand":"Evolution Racewerks","offers":[{"title":"Catless — Brush Finish","offer_id":43280679534653,"sku":"EW-EXH-ER-N55-CATLESS","price":615.0,"currency_code":"USD","in_stock":true},{"title":"Catless — SwainTech White Lightning","offer_id":43280679567421,"sku":"EW-EXH-ER-N55-CATLESS-CER","price":865.0,"currency_code":"USD","in_stock":true},{"title":"High-Flow Catted — Brush Finish","offer_id":43280679600189,"sku":"EW-EXH-ER-N55-CAT","price":965.0,"currency_code":"USD","in_stock":true},{"title":"High-Flow Catted — SwainTech White Lightning","offer_id":43280679632957,"sku":"EW-EXH-ER-N55-CAT-CER","price":1215.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0658\/2553\/8109\/files\/er-n55-downpipe-01.webp?v=1781743119","url":"https:\/\/essewerks.com\/products\/er-n55-downpipe","provider":"Esse Werks","version":"1.0","type":"link"}