Wagner Tuning BMW F-Series N55 Catless Downpipe Kit -6/13

Wagner Tuning BMW F-Series N55 Catless Downpipe Kit (Up to 06/2013)

If you want to unlock more performance from your BMW N55-powered F-Series, replacing the restrictive factory downpipe is one of the most effective exhaust upgrades available. This catless downpipe from Wagner Tuning is engineered specifically for the N55 engine, designed to reduce exhaust backpressure so gases can exit the turbocharger more freely. The result is improved power delivery, sharper throttle response and a stronger torque curve.

Wagner Tuning have built this as a direct replacement for the standard BMW Y-pipe assembly. It fits in place of the original part with no modification required, making installation straightforward for an experienced mechanic. It replaces original BMW part number 18328603875.

What Sets This Downpipe Apart

The pipe features a 76mm diameter bore, larger than the stock unit, which allows exhaust gas to flow more freely away from the turbocharger. The connection at the turbo outlet measures 105mm, matching factory dimensions for a clean, secure fit. Two lambda probe (oxygen sensor) ports are included to maintain compatibility with the car’s standard sensor locations.

Construction is from 1.4301 grade stainless steel (also known as SS304), a corrosion-resistant, high-quality material that copes well with the heat and conditions of both daily driving and performance use. The design is CAD-developed, meaning it has been digitally engineered for accurate fitment and consistent quality across every unit produced.

Performance Benefits

By removing the main catalytic converter from the exhaust path, backpressure is significantly reduced. This benefits the turbocharger by lowering heat stress and allowing it to spool (spin up) more efficiently. In real terms you can expect:

• Improved throttle response
• A noticeable increase in torque, particularly in the mid-range
• More usable power across the rev range
• A deeper, more characterful exhaust note

Compatible Vehicles

This downpipe kit fits the following BMW F-Series models equipped with the N55 engine, built up to June 2013:

• BMW M135i / M135ix – F20 / F21 (up to 06/2013)
• BMW 335i / 335ix – F30 / F31 / F34 (up to 06/2013)
• BMW 435i / 435ix – F32 / F33 (up to 06/2013)

Please use the vehicle lookup tool on this site or check the Vehicle Fitment tab to confirm compatibility with your specific car before purchasing.

Technical Specification

Important: ECU / Software Note

After fitting this downpipe, the software map in your DME (the car’s engine management system) must be updated to prevent fault codes being triggered by the removal of the catalytic converter. This is an essential step and should not be overlooked. Without a remap, the car will register a check engine light and may enter a reduced performance mode.

Important: Legal and Usage Notice

This is a catless downpipe and does not include a catalytic converter. Removing the catalytic converter from a road-going vehicle is not legal for use on public roads in the UK and many other regions, and the vehicle will not pass an MOT emissions test in this configuration. This product is intended for motorsport, off-road or track use only. It is the buyer’s responsibility to ensure compliance with all local laws and regulations.