BMW S50

BMW M50 engine
Overview
Manufacturer	BMW
Production	1990–1996
Combustion chamber
Configuration	Straight-6
Chronology
Predecessor	BMW M20
Successor	BMW M52

The BMW M50 is a straight-6 DOHC piston engine was produced from 1990-1996. It was released in the E34 520i and 525i, to replace the M20 engine. It began to be phased out following the introduction of the M52 engine in 1994.

Compared with its M20 predecessor, the M50 features DOHC, 4 valves per cylinder, coil-on-plug ignition, a knock sensor and a lightweight plastic intake manifold. As per the M20, the M50 uses an iron block with an alloy head.

In September 1992, the M50 was upgraded to the M50TU ("technical update"), which added variable valve timing to the intake camshaft (called single VANOS by BMW).

The E36 M3 was powered by the S50 engine series, which is a high output version of the M50.

The 1,991 cc (121 cu in) M50B20 was introduced with the 1990 520i. It has an 80 mm (3.1 in) bore and 66 mm (2.6 in) stroke and produces 110 kW (150 hp). Compression Ratio 10.5:1.

Applications:

The M50B20 was updated with single VANOS in 1992. Compression Ratio raised to 11:1. Peak torque became available at 4200 rpm.

Applications:

This is a 2.4 L engine used in the Thailand and Oceania markets. It is based on the 2.5 L M50B25 with a reduced stroke.

The 2,494 cc (152 cu in) M50B25 was introduced with the 1990 525i and 525ix. It has an 84 mm (3.3 in) bore and 75 mm (3.0 in) stroke and produces 141 kW (189 hp) at 6000 rpm and 245 N·m (181 lb·ft) at 4700 rpm.

Applications:

The M50B25 was updated with single VANOS in 1992. Peak torque became available at 4200 rpm.

Applications:

The S50 is the high performance version of the M50 which was used in the M3. Like the M50, it has an iron block and aluminum head with four valves per cylinder.

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