Will the 25 year old BMW M3 move to a turbo-four engine
In the mid-1980’s Duran Duran and the Scorpions blared into the ears of Americans and Germans from yellow Walkman cassette players the size of shoe boxes. Meanwhile, BMW was thinking hard about diving into the German touring car race series known as “A-Group.”. The car they had in mind for the series was the 3-series. That car is absolutely defined by the “Smooth-six” in-line six cylinder engine. Car magazines and enthusiasts discovered BMW had a project underway to create the race car and then build a street version and everyone assume the car would either be a super-six or some kind of turbo-four along the lines of the turbocharged Audi Quattro (an in-line 5). Everyone was wrong.
Four Cylinder Wonder
The first BMW M3 was a 2.3 liter normally aspirated (Non-turbo) four cylinder car that featured the then exotic 4 valves per cylinder heads just starting to become available. Paul Rosche was the technical director of what was then the BMW motorsports division. He can sum up the engine development better than anyone saying “We started work immediately. One advantage was that the big six-cylinder engine originally had the same cylinder gap as the four-cylinder engine. We therefore cut two combustion chambers off the four-cylinder head of the M88 and bolted a panel over the hole on the rear side.” That was the starting point. The end result was an engine that had incredible power and responsiveness for a four cylinder. What does this mean for BMW today? It means that BMW is not afraid to step away from the in-line six when it feels the car can do better with some other arrangement.