Stone Exhaust BMW N55 Catless Decat Downpipe (F20 F21 F22 F23 F30 F31 F32 F33 F36, F25 X3 35i, F26 X4 35i) - M135i M235i 335i 435i - PWG/EWG

High-Flow De-Cat Turbo Outlet for BMW N55 F-Series – Track Use Only

Transform the way your turbocharged straight-six responds with this Stone Exhaust de-cat turbo outlet for BMW N55 platforms. Expect faster boost build, sharper throttle, a harder-hitting mid-range and that addictive N55 soundtrack. This is the go-to performance front pipe for enthusiasts chasing a genuine step-up in response and sound on F-series 1 Series, 2 Series, 3 Series, 4 Series plus F25 X3 35i and F26 X4 35i.

If you are searching for N55 performance front pipe, N55 de-cat turbo pipe, BMW M135i race pipe, M235i turbo outlet, F30 335i performance exhaust front section, F32 435i upgrade pipe, F25 X3 35i de-cat or F26 X4 35i high-flow turbo outlet, this premium one-piece unit is the smart choice.

What makes it outstanding

• One-piece, high-flow design engineered to reduce backpressure and maintain gas speed for quicker spool and stronger torque
• 7 axis CNC mandrel bending preserves roundness through tight radii for excellent flow stability
• Unique flex section absorbs heat cycling and vibration to protect the assembly from stress and cracking
• Turbo flange features crisscross and overlapping welds for strength under extreme temperature load
• Robotic welding for repeatable, clean penetration and consistent quality inside and out
• Developed using 3D scanning with flow simulation to optimise diameter, routing and bend geometry
• Direct bolt-on with OEM style fitment for F-series N55 applications

Real-world gains you can feel

Free up the N55’s breathing and let the turbocharger work more efficiently. The result is a more urgent throttle, quicker boost response and a deeper, more aggressive exhaust tone that comes alive under load. Perfect foundation for Stage 2 calibration and performance tuning on M135i, M235i, 335i and 435i, as well as X3 35i and X4 35i.

Fitment coverage

BMW 1 Series

• F20 M135i and M135i xDrive
• F21 M135i and M135i xDrive

BMW 2 Series

• F22 M235i and M235i xDrive
• F23 M235i and M235i xDrive

BMW 3 Series

• F30 and F31 335i and 335i xDrive

BMW 4 Series

• F32 435i and 435i xDrive
• F33 435i and 435i xDrive
• F36 435i and 435i xDrive

BMW X Series

• F25 X3 xDrive35i
• F26 X4 xDrive35i and X4 M40i xDrive (N55)

PWG and EWG variants with part numbers

Choose the version that matches your wastegate type:

• PWG Pneumatic Wastegate – Part number A201P
• EWG Electronic Wastegate – Part number A202P

Unsure which you have? A vacuum line to the actuator indicates PWG. An electrical plug indicates EWG. Ask our team if you need assistance.

Engineering detail

• Reverse engineered from OEM hardware using 3D scanning to identify restrictions and improve the gas path
• Precision bending retains up to 98% roundness through curves to keep velocity high
• Internal surfaces kept smooth by robotic welds to avoid intrusive weld bead and turbulence
• Tight manufacturing tolerances target accurate fit and consistent performance

Installation and mapping

Professional fitting is recommended. For a seamless install and optional calibration support, book with MJ Modifications in Warwickshire. Request a quote at info@mjmodifications.co.uk. An ECU calibration is recommended after installing a de-cat turbo outlet to optimise performance and manage potential warning lights.

Tried and approved by enthusiasts

We have fitted multiple Stone Exhaust N55 units at MJ Modifications and customer feedback has been consistently positive. Owners love the OEM-like fit, the quality of the welds, the refined yet purposeful tone at idle and the lively response once mapped.

Warranty and manufacturer

Manufacturer: Stone Exhaust

Warranty: 2 Year Manufacturer Warranty

Important notice

This de-cat front pipe is intended for off-road and motorsport use where permitted. Please check local regulations before purchase and installation.

Media

Stock vs Stone Exhaust de-cat turbo outlet

Installed photos

BMW N55 F30 335i Stone Exhaust sound

Popular search phrases

BMW N55 performance front pipe UK, N55 turbo outlet upgrade, BMW M135i de-cat pipe, M235i performance exhaust front section, F30 335i turbo down pipe replacement, F32 435i race pipe, BMW 1 Series F20 F21 turbo elbow, BMW 2 Series F22 F23 de-cat exhaust, BMW 3 Series F30 F31 N55 tuning hardware, BMW 4 Series F32 F33 F36 turbo outlet pipe, X3 35i F25 N55 exhaust upgrade, X4 35i F26 N55 de-cat, N55 PWG pipe A201P, N55 EWG pipe A202P, Stage 2 N55 hardware, high flow N55 turbo pipe, BMW F-series N55 exhaust mod, M135i performance exhaust component, 335i turbo back upgrade, 435i cat delete front pipe.