BMW N55 4-Inch Stainless Steel Decat Downpipe | 135i 235i 335i 435i (F20 F22 F30 F32) – Midnight Performance

Midnight Performance BMW N55 4-Inch Stainless Steel Decat Downpipe | F2X / F3X

The single most effective bolt-on upgrade for your N55. Replace the factory catalytic converter with a 4-inch T304 stainless straight-through pipe — slashing backpressure at source, sharpening turbo response, and unlocking the aggressive exhaust character the N55 was always capable of. The foundation for any serious Stage 2 or Stage 3 build.

Key Features

• 4-inch (102mm) straight-through bore — maximum flow directly from the turbo housing
• T304 stainless steel — corrosion-resistant and built for sustained high-heat use
• Mandrel-bent, TIG welded — smooth internal bore profile for unrestricted exhaust scavenging
• Direct bolt-on fitment — no fabrication or vehicle modification required
• Noticeably sharper turbo spool — faster boost build, cleaner throttle transitions
• Deeper, more aggressive exhaust note — transforms the sound of your N55

Technical Specifications

Vehicle Compatibility

• BMW 135i — F20 / F21 (2011–2015)
• BMW 235i — F22 / F23 (2014–2020)
• BMW 335i — F30 / F31 / F34 (2012–2019)
• BMW 435i — F32 / F33 / F36 (2013–2020)

N55B30 only. Not compatible with S55 (M3/M4) or N54 engines. Please verify your engine code before ordering.

⚠️ Off-road and track use only. This decat pipe removes the catalytic converter and is not road legal in the UK. A Stage 2 ECU remap is strongly recommended after fitting to clear engine management lights and maximise performance gains.

Professional Fitting Available in Birmingham

Our Birmingham workshop can fit this for you. Contact us for a quote.