Based on the 1986 model year
E30 3-Series,
the first M3 was introduced with a 2.3 L I4S14B23 engine (or S14 in shorthand). The engine design was based on various BMW genealogy; basic block layout from the M10 4 cylinder (found in the 2002 and 320 series) overbored and reinforced to similar specifications of the
BMW M88 inline-6. The valve train and head architecture from BMWs M1 and later M6 inline-6 cylinder was adopted for aggressive breathing, resulting in outstanding performance for the day.
The most notable characteristic of the E30 M3 (relative to later M3 iterations) is its racing pedigree. It was campaigned by BMW as well as other racing teams including
Prodrive and
AC Schnitzer competing in many forms of racing including Rally, German, British, Italian, Belgian, French and Australian touring car.
One of the main reasons for production of the road car was to
homologate the M3 for
Group A Touring Car racing. One of the reasons often cited for its creation was that it was to compete with the "2.3-16V"-model of the
Mercedes-Benz W201 190E which was introduced in 1983, although this was only speculative.
When the E30 M3 was in its final years of top level competition, the 2.5 liter S14 engine in full race trim was capable of over 340 hp (250 kW) naturally aspirated.
