Active Autowerk Equal Length Midpipe F87 M2Compétition/CS

Description

For over 39 years, Active Autowerke has been an industry leader in the design of high-quality BMW performance products. Committed to enhancing the driving pleasure of your vehicle through the highest quality products, Active Autowerke is recognized as the leader in BMW innovation. Our philosophy of developing refined BMW performance parts and offering them to the entire BMW community is exemplified by our latest R&D program focused on improving the sound of the S55 exhaust. This R&D program resulted in the development of the Active Autowerke Equal Length Mid Pipe for the F80 M3 and F82 M4 (US Patent No. 11248511, pending in the UK and EU), an alternative to the popular F8X Single Mid Pipe.

An inline 6-cylinder engine naturally has evenly spaced exhaust pulses, which produces a smoother, fuller sound. However, the S55 engine's twin turbochargers, while producing increased power, produce a sound more reminiscent of two independent inline 3s competing for noise rather than the throaty sound one might expect. The nearly 45-inch gap between the length of the front and rear downpipes creates uneven pulses. So, when merged with a crossover system, whether stock, X-pipes, dual X-pipes, a single midpipe, or a tail section, because the sound waves travel at the same speed as they exit the system, these crossover sections simply produce a higher-pitched sound, resulting in that annoying noise some have referred to as "brushcutter noise." Current systems allow banks to blend unequally pulsed sounds, and after much research and testing (by many BMW experts), it was determined that equalizing the length of the exhaust pipes before blending was a solution to this sound problem.

Early exhaust solutions aimed to address this variation in space behind the differential housing, with one issue being the inability to retain existing rear exhaust systems. Active Autowerke decided to leverage its expertise, gained from developing a unique mid-pipe system for the F-series M models, and dedicated its R&D resources to developing the mid-pipe solution shown here. Our R&D team investigated possible solutions, and while compensating for the difference at the rear of the exhaust seemed the most logical location, this would require an entirely new rear exhaust system, and we were aware that many BMW owners would not appreciate this option. We therefore considered extending the passenger-side mid-pipe section and creating a new crossover section to produce an exhaust note unlike anything ever heard on an S55. Using a patented crossover solution with sine pipes allowed us to correct for the variation in downpipe length before blending the sounds to achieve the expected sound of a 6-cylinder sports car.

The Active Autowerke F8X Equal Length Mid Pipe has been specifically designed to create equal length exhaust pipes, fitting the difference between the front and rear rows of the F80 M3 and F82 M4 downpipes, before integrating an X-pipe, creating an exhaust note unlike that of a classic S55. Designed to perfectly fit the F80 M3 and F82 M4, this mid pipe will allow you to hear the difference in sound from the first try, with open throttle!

NOTE: IT IS STRONGLY RECOMMENDED THAT CARS EQUIPPED WITH CATALYST DOWNPIPE USE THE RESONATOR OPTION FOR THE EQUAL LENGTH MIDDLE PIPE.

MAIN FEATURES
Lighter than the factory system
Faster turbo spool
Increased power in the low and mid ranges
Equal length design eliminates pulsating noise caused by unequal length downspouts