The BMW S14 is a straight-4 DOHC piston engine which was used in the E30 M3. It is based on the M10 block and the M88 head with two cylinders removed. The successor to the S14 is the S50 six cylinder engine (since it was used in the following M3).

The E30 M3 was initially released with the 147 S14B23. Versions equipped with a catalytic convertor produced 143 kW (194 PS) and 230 Nm.

Applications:  1986-1990 E30 M3