Evolution Racewerks Competition Series Mid-Pipe for G8X M3 & M4
Restrictions in the exhaust system robs horsepower and torque especially on turbocharged cars. Thus, removing as much exhaust flow restrictions will increase horsepower and torque. The factory resonators found in the factory midpipe is designed to muffle and quiet the exhaust flow however this causes a restriction to the exhaust flow. Evolution Racewerks' Competition Series Midpipe deletes the resonators from the exhaust system to improve exhaust flow. Coupled with mandrel bent tubing which also helps promote better flow, increase horsepower and torque can be had. At the same time, a more aggressive exhaust sound is produced.
ER's Competition Series Mid-pipe feature a "H" style crossover. The crossover is used to equalize the pressure between the left and right exhaust pipes. This helps promote better flow and reduce droning. Through testing between an "X" and "H" crossover design, we found the "H" crossover design helped reduce droning and improving low end torque compared to the "X" crossover design. Thus, they incorporated an "H" crossover instead of a "X" crossover. At the end of the day, this is a BMW and we do not want droning. The factory mid pipe also incorporates a "H" crossover design so ER figured BMW also felt the "H" design was the ideal solution for this application.