Active Autowerke BMW F80 M3 & F82/F83 M4 Gen 2 Equal Length Midpipe

The Active Autowerke Gen 2 Equal Length Midpipe for the BMW F80 M3 and BMW F82/F83 M4 is the result of years of in-depth research and development aimed at solving one of the most commonly criticised aspects of the S55 engine – its exhaust tone. Unlike conventional crossover or X-pipe designs, this patented system corrects the unequal exhaust pulse timing created by the factory downpipe length difference, delivering a smoother, deeper and more natural inline-six sound.

The S55’s twin-turbo layout creates a significant variance in exhaust runner length between the front and rear banks, causing unevenly spaced exhaust pulses that lead to rasp, high-pitched tones and the well-known “2k rpm buzzing”. Active Autowerke’s equal length design adds length to the shorter side of the system and uses a patented sinusoidal crossover to synchronise exhaust pulses before they merge. The result is an exhaust note that finally sounds like a true performance-focused six-cylinder engine.

Gen 2 introduces specially developed resonators, engineered specifically to remove rasp and reduce unwanted buzzing with minimal impact on overall volume. This version replaces the original Gen 1 equal length midpipe and is now the definitive solution for refining S55 exhaust sound while retaining strong performance gains. The system is engineered for precise fitment and includes the Active Autowerke F-brace.

Key Features

• Equal length midpipe design to correct uneven exhaust pulses

• Gen 2 bespoke resonators to reduce rasp and 2k rpm buzzing

• Noticeably smoother, deeper and more refined exhaust tone

• Lighter than the factory midpipe system

• Quicker turbo spool

• Improved low-end and mid-range power

• Includes Active Autowerke F-brace

• Designed and engineered specifically for the S55 platform

Resonated vs Non-Resonated Guidance

• Strongly recommended for vehicles running catless downpipes to choose the resonated version

• Vehicles with aftermarket downpipes should use the resonated option

• With stock downpipes, minor rasp may still be present – resonated version advised

• Vehicles fitted with M Performance Exhaust (MPE) or CS exhaust should strongly consider the resonated version

Fitment and sound results are only validated with stock or Active Autowerke downpipes and rear exhaust systems. Compatibility with other exhaust brands is not guaranteed.

Compatibility

• BMW F80 M3 (2014–2018)

• BMW F82 M4 Coupe (2014–2020)

• BMW F83 M4 Convertible (2014–2020)

Engine: S55 3.0L Twin-Turbo Inline-Six

Important Notes

• Designed for use with OEM or Active Autowerke rear exhaust systems

• Results and fitment cannot be guaranteed with other rear exhaust manufacturers

• Cars with straight-through (catless) downpipes should always select the resonated option

Backed by over 41 years of BMW-specific engineering expertise, the Active Autowerke Gen 2 Equal Length Midpipe is one of the most technically advanced and proven solutions available for transforming the sound and response of the F8X M platform.

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