BMW M Evolution, Part 3: The First M3 - And With a Four Cylinder Engine

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The first M3 enjoyed an idiosyncratic design and a lot of success in motorsport activity.

"Mr. Rosche", Eberhard von Kuenheim, the BMW Chairman, said to Paul Rosche, engineering manager of M GmbH, "we need a sporty engine for the 3 Series." With that, von Kuenheim set the tone for generations of M automobiles to come. "Whether you believe it or not - we had created an outstanding four-cylinder engine for the 3 Series within the space of two weeks," said Rosche. "Under the development name S14, this engine generated headlines in sport and volume production over the years to come.

One Sunday, I drove to von Kuenheim's flat and gave him the car for a test drive. When he came back he said: 'Good, I like it.' And that's how the M3 came into being." The main attribute of the M series in all its guises is what lies at the front of the car, i.e. its engine. Power plants were always the pride and joy of the Bavarian marque as exterior design and other non-functional essentials were less of a priority. Of course a powerful engine cannot live up to customers' expectations without improved chassis components, but in BMW's case they were always secondary in importance to the engine.

Therefore it is no wonder that the technician who was chosen and was most competent to lead the development team was Paul Rosche, a mechanical engineer with sound knowledge and experience of engine design. In addition to his duties at M GmbH, Rosche also headed the F1 turbo engine project which had powered Nelson Piquet to the 1983 F1 World Championship driving a Brabham-BMW. That was a unique engine in the F1 field, based on an inline four-cylinder block, as opposed to the V-configuration of most other competitive F1 engines.

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The reason was probably frugality; BMW had an off the shelf block which could be adapted to Formula 1 (and in qualifying setup could produce up to 1500hp). To go back from F1 to a powerful sportive engine in a road car posed different challenges to the designers. And having an F1 engine block in your car was also something special. The first M3 appeared in model year 1986, based on the E30 platform and with two variants, a two-door coupe and a convertible. It was equipped with a 2.3-liter engine, which was assembled of components from various BMW engines.

The four-cylinder block was taken from the M10 engine which was developed for the New Class series. It was over bored and reinforced to the M88 inline-6 engine block specifications. Head architecture and valve train were copied from the M1 engine. Later, the M6 inline-6-cylinder was adopted for aggressive breathing. Engine output was at 200hp and a top speed of 146 mph. Testing on the Nurburgring was hard on materials, particularly on the exhaust system. The cause was unplanned growth in the exhaust system because of high temperatures at full load as the system expanded up to 25 mm and became distorted within its mounting.

A simple set of different washers solved the problem and the car was successfully tested at high speed at the Nardo test track. The M3 body was different to the regular E30 due to 12 new panels that were supposed to improve aerodynamic efficiency. The bodywork was made of metal and only front and rear bumpers, side sills, trunk and spoilers were made of lightweight plastic, so the E30 M3 weighed in at 2,568 lbs. and remained a sporty lightweight with only 12.8 lbs. for every 1 horsepower. The E30 M3 was in production for six years in which it campaigned extensively as a works team in international racing and international rallying.

It was homologated for Group A Touring Car racing and also found a true adversary in the Mercedes-Benz 190E 2.3-16V that was introduced in 1983. In its final years of competitions, known as Evolution III (or Sport Evolution), the 2.5-liter S14 engine in full race trim was capable of over 250hp. The M3 road-going version produced 195hp. Evolution models continued with the 2.3-liter engine though with a few improvements such as a revised intake camshaft profile and modified exhaust camshaft timing, increased compression, and a more efficient cylinder head intake port design that increased output to 220hp.

Larger wheels, thinner rear and side window glass, a lighter trunk, a deeper front spoiler and an additional rear spoiler, were found on the evolutions models. As expected, these original M3s have increased in value over the years and are highly sought after by collectors.


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