The BMW S14 is a 2.3 L (2302cc) DOHC 16-valve I4 piston engine. It was used in the E30 M3. The S14 is essentially a BMW M10 engine block with a M88/S38 DOHC cylinder head (minus two cylinders). It has four separate throttle bodies. It developed 195 PS (143 kW/192 hp), or 200 PS (147 kW/197 hp) without a catalytic converter. A special tuned model, the S14 EVO producing 20 PS more. The 2.3 L version has a 93.4 mm bore and 84mm stroke.
Variations of this engine included a limited-edition 2.5 L (2467 cc) Sport Evo for motorsport homologation requirements, and a 2.0 L (1990cc) version with stroke reduced to 72.6 mm (often described incorrectly as being "sleeved" or of reduced bore) for the 320is, a sports model made specifically for the Portuguese and Italian markets. The 320is can be quickly distinguished from the E30 M3 by the absence of flared wheel arches.