We were fortunate enough to produce significant naturally aspirated power gains during the testing of our S52 vs. M50 Manifold and the Turner Motorsport Stage 2 & 3 packages for the BMW E36 M3 without breaking the bank, but the list of ways to further increase power with bolt-ons has shrunk considerably.
The US-Spec E36 M3 is arguably the most mundane variant of the M3 and we have made a lot of progress to inch ours closer to its 321hp European counterpart. While we gained a lot of power and some audible character by freeing up the intake of our S52 motor, the stock muffler mutes the exhaust note to a level more suitable for a 7-series than an M3.
To free up both power and sound we installed a Borla Cat-Back Sport Exhaust (Part 3) which was designed specifically for the S52 and the E36 M3. Borla did not just use a standard off the shelf muffler, but rather tailored the design to suit the needs of the M3’s inline-6 to extract the most power possible with a refined sound. We went with Borla due to their reputation for producing industry leading products and because their E36 M3 cat-back is more aggressive than stock without droning or screaming ‘look at me’, which is exactly what we are looking for in this daily driver.
Borla has found that for street use, large diameter pipes take energy out of the exhaust by slowing down the exhaust flow and by cooling off the gasses. Furthermore, big pipes increase the low frequency range which increases the unwanted drone. Borla exhaust systems are designed for less restriction and keeping the velocity and frequency high to both reduce drone and improve sound quality.