The E92 BMW M3, produced from 2007 to 2013, is widely considered one of the finest performance cars of its generation. Its 4.0-litre naturally aspirated V8 — the S65, developed exclusively for M division — revved to 8,300 rpm, produced 414 horsepower, and made a sound that automotive journalists ran out of superlatives trying to describe. It won awards. It won comparison tests. It is now appreciating on the used market as collectors recognise what it represented.
The engineers who built it wanted to make a six-cylinder instead.
How the V8 Happened
To understand the decision, you need to understand the competitive context of the mid-2000s performance car market. The M3’s principal rivals — the Mercedes-Benz C63 AMG and the Audi RS4 — were both moving to V8 engines. The cylinder count arms race was underway. Marketing and product planning departments across the industry had concluded that customers equated more cylinders with more prestige, and that a six-cylinder M3 competing against V8 rivals would face a perception problem regardless of what the stopwatch said.
BMW’s M division received the brief: the next M3 should have a V8.
The engineers complied. But several of them were not pleased about it, and in interviews given after the car’s production ended, some were candid about their reservations.
The Six-Cylinder Preference
BMW M’s identity had been built, across multiple decades, on the straight-six engine. The E30, E36, and E46 M3s all used inline-six units. The format was central to BMW’s brand character — the company had long positioned itself as the world’s preeminent developer of the configuration, and there was institutional pride as well as engineering rationale behind it.
The straight-six’s advantages in an M3 application were specific. Its longer stroke and torque characteristics suited the kind of driving the M3 was designed for: corner exit traction, mid-range response, progressive power delivery. A high-revving V8, by contrast, produces its power higher in the rev range, rewarding drivers who are willing to work for it but potentially frustrating those who want the engine to co-operate across a broader band.
M division’s engineers, by multiple accounts, felt the six-cylinder was the more honest tool for the M3’s intended purpose. The V8 was the more impressive number on a spec sheet.
The S65 in Practice
What BMW M actually delivered, whatever the internal debate, was exceptional. The S65 was not a detuned version of any existing BMW engine — it was developed from scratch for the M3, sharing architecture with the S85 V10 used in the contemporary M5 but reconfigured significantly. Its flat-plane crankshaft gave it the high-revving character of a racing engine. Its throttle response was near-instantaneous. The sound at full chat, with all eight cylinders firing in a car with a well-sorted exhaust, remains one of the more viscerally satisfying noises a production car has made.
The irony is that the very qualities M division’s engineers were concerned about — the need to rev the engine hard to access its performance, the top-end focus of its power delivery — became the things that enthusiasts loved most about it. The S65 rewards commitment. It asks something of the driver. In that respect, it turned out to be entirely consistent with M division’s values even if it arrived by a route some of the engineers had not preferred.
The Return of the Six
The E92’s successor — the F80 M3, launched in 2014 — returned to a six-cylinder engine. The S55 was a twin-turbocharged inline-six, more powerful than the S65, faster around a circuit, and technologically more sophisticated in almost every measurable way.
Enthusiasts were divided. The turbocharged six produced more torque at lower revs, which made it faster but also, to some ears, less interesting. The F80 was undeniably capable; it was also, to a significant portion of M3 devotees, a car that didn’t ask as much of its driver as the V8 had.
BMW M division, in going back to a six, got something close to what they had originally wanted. Whether that was the right outcome depends entirely on what you think the M3 is for.
What This Tells Us About Car Companies
The E92 M3 story is a clear-eyed illustration of how performance cars are actually made. Engineering judgement, marketing requirement, competitive positioning, and institutional identity all pulled in different directions simultaneously. The car that emerged was exceptional — but it was exceptional partly in spite of the process that produced it, and the people most responsible for its engine were not entirely convinced they had been given the right brief.
That tension — between what engineers want to build and what product planners decide the market requires — runs through the history of almost every significant performance car. The E92 M3 is simply one of the more documented examples of it surfacing openly.
