Having moved away from the previous generation’s 4.0-litre naturally-aspirated V8 for a twin-turbo six-cylinder engine, the new fifth-generation BMW M3 and M4’s engine note was always going to be a hot topic.
Although loud and still very aggressive-sounding at high speed, the new exhaust note is substantially different to M cars of the past, but is that a bad thing?
Speaking to CarAdvice at the international launch of the new M cars in Faro, Portugal, Norbert Siegl, project manager for the M3/M4 engines, said that while plenty of attention was given to the exhaust note, it was never about trying to replicate the V8 bark of its predecessor.
“It’s no V8, that’s real and it couldn’t be the [V8] sound.” Siegl said. “It should be really realistic to the engine we’ve created here.”
With the new 3.0-litre twin turbo six-cylinder engine (which differs to the single twin-scroll turbo found in cars prefixed with the ’35i’ designation), the twin exhaust system is substantially different to it predecessor.
The exhaust system, which is unique to the M3/4, uses two flaps that open depending on vehicle speed (the previous M3 had no exhaust flaps), engine RPM and load.
If the flaps are closed the whole exhaust goes through the damper but with the flaps open, air is guided directly to the twin exhausts, bypassing the damper and making for a much louder sound.
Siegl says there was no point trying to reproduce a V8 sound and the M division “wanted to make it have its [own] unique character”.
Despite its differences in exhaust note, the new M3 and M4 has more power and substantially more torque than the previous model, while the 0-100km/h time is cut down by over a second.
Are the performance increases enough to justify the change of tune? You can listen to the engine note in this video: