BMW M50

M50B20

M50 engine in BMW Museum

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 PS). The compression ratio is 10.5:1.^[7]

Applications:

• 1990-1992 E34 520i
• 1991-1992 E36 320i

M50B20TU

The M50B20 was updated with single VANOS in 1992. Peak torque became available at 4200 rpm.^[7] It produces 110 kW (150 PS) at 5900 rpm and 190 N⋅m (140 lb⋅ft) at 4200 rpm. The compression ratio was raised to 11.0:1.

Applications:

• 1992-1994 E36 320i
• 1992-1996 E34 520i

M50B24TU

This is a 2.4 L engine used in the Thailand and Oceania markets.^[8] It is based on the 2.5 L M50B25TU with the stroke reduced to 72 mm (2.8 in) and produces 138 kW (185 hp) (188 PS) at 5900 rpm and 240 N⋅m (177 lb⋅ft) at 4200 rpm. The compression ratio was 10.5:1.

Applications:

• 1993-1995 E36 325iA/2.4
• 1992-1996 E34 525iA/2.4

M50B25

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) (192 PS) at 6000 rpm and 245 N⋅m (181 lb⋅ft) at 4700 rpm.^[7] The compression ratio is 10.0:1.

Applications:

• 1990-1992 E34 525i, 525ix
• 1991-1992 E36 325i, 325is

M50B25TU

The M50B25 was updated with single VANOS in 1992, resulting in peak torque becoming available at 4200 rpm. It produces 141 kW (189 hp) (192 PS) at 5900 rpm and 250 N⋅m (184 lb⋅ft) at 4200 rpm.^[7] The compression ratio was increased to 10.5:1.

Applications:

• 1993-1995 E36 325i, 325is
• 1992-1996 E34 525i, 525ix

S50B30

The S50B30 is a 2,990 cc (182 cu in) higher output version of the M50 which powered the E36 M3, except in the United States. In Canada, BMW officially imported 45 M3s produced in late 1993 with the S50B30 engine.^[9][10]

The S50B30 produces 210 kW (282 hp), has a bore of 86 millimetres (3.4 in), a stroke of 86 millimetres (3.4 in) and a compression ratio of 10.8:1.^[11][12] The redline is 7,600 rpm. The S50 has an individual throttle body for each cylinder, variable valve timing (called "VANOS" by BMW) on the intake camshaft, Motronic M3.3 engine management and redesigned intake and exhaust systems.^[9]

The limited edition "M3 GT" model from 1995 produced 220 kW (295 hp).^[9] It had different camshafts and a redesigned sump and oil pump.

Applications:

• 1992-1995 E36 M3 (except for US)

S50B30US

In the United States, the 1994-1995 M3 is powered by a 3.0 L tuned version of the M50 which produces 179 kW (240 hp).^[9][13] This engine was based on the M50B25TU and uses the same compression ratio,^[9] but uses a different crankshaft, connecting rods, and pistons. The bore is 86 mm (3.4 in), stroke is 86 mm (3.4 in) and the redline is 6,500 rpm.^[14]

In 1996, the S50B30US was replaced by the 3.2 L S52 (in the United States and Canada only).^[15]

Applications:

• 1994-1995 E36 M3 (US only)

S50B32

In 1996, the S50B32 replaced the S50B30 (except in Canada and the United States, where the S52 engine was used instead).^[16] Power output increased to 321 PS (316.6 bhp; 236.1 kW) at 7400 rpm and 350 N⋅m (258.1 lb⋅ft) at 3250 rpm of torque.^{[17] [18]} and the displacement increased to 3,201 cc (3.2 L; 195.3 cu in), due to an increased stroke of 91 mm (3.58 in) and a slight increase in bore to 86.4 mm (3.40 in).^[19]

Variable valve timing is fitted to both camshafts and a secondary oil pick-up was added (from the "M3 GT" version of the S50B30).^[20] The compression ratio is 11.3:1 and the redline is 7,400 rpm.^[21] Engine management is provided by a Siemens MSS50, with 3 knock sensors.

Applications:

• 1996-1999 E36 M3 (except Canada and the United States)
• 1996-1999 Z3 M Coupe and M Roadster (except Canada and the United States)