| Manufacturer | BMW |
|---|---|
| Production | 1989–1994 |
| Predecessor | BMW M20 |
| Successor | BMW M52 |
| Class | Straight-6 |
The BMW M50 is an I6 piston engine. It was introduced in March 1989 to replace the BMW M20 and was replaced by the BMW M52 in 1995. Displacement ranges from 2.0 L to 3.2 L. It is a DOHC 24-valve engine. A Technical Update or M50TU version from 1992 introduced VANOS variable valve timing. When this technology was introduced, it was known as VACC or Variable Camshaft Control.
The M50 was not related to the M20 though it used the same 91 mm cylinder spacing, bore, and stroke at 2.0 L and 2.5 L.
| Engine | Displacement | Power | Torque | Redline | Bore | Stroke | Year |
|---|---|---|---|---|---|---|---|
| M50B20 | 2.0 L (1991 cc/121 in³) | 110 kW (150 hp) @ 6000 | 190 N·m (140 ft·lbf) @ 4700 | 6750 | 80mm | 66mm | 1989 |
| 110 kW (150 hp) @ 5900 | 190 N·m (140 ft·lbf) @ 4200 | 6750 | 80mm | 66mm | 1992 | ||
| M50B24 | 2.4 L | 138 kW (188 hp) @ 5900 | 235 N·m (177 ft·lbf) @ 4700 | 6550 | 84mm | 72mm | 1989 |
| M50B25 | 2.5 L (2494 cc/152 in³) | 141 kW (192 hp) @ 6000 | 245 N·m (181 ft·lbf) @ 4700 | 6500 | 84mm | 75mm | 1989 |
| 141 kW (192 hp) @ 5900 | 250 N·m (184 ft·lbf) @ 4200 | 6500 | 84mm | 75mm | 1992 |
Contents |
M50B20
The 2.0 L (1991 cc) M50B20 was introduced with the 1989 520i. It has an 80 mm bore and 66 mm stroke and produces 150 hp (110 kW). From the '93 model year onwards, the engine received a 'technical update' which included the addition of VANOS (VAriable NOckenwellen Steuerung), BMW's variable valve timing system, on the intake cam. The engine thereafter became known as the M50TUB20.
Applications:
M50B24
This is a 2.4 L engine based on the 2.5 L M50B25, with a reduced stroke. This engine is only fitted to CKD kits assembled in Thailand. Power output is 188 hp (140 kW) and torque is 134 ft·lbf (235 Nm).
Applications:
M50B25
The 2.5 L (2494 cc) M50B25 was introduced with the 1991 525i/525ix . It has an 84 mm bore and 75 mm stroke and produces 192 PS (141 kW; 189 hp) @5900 rpm and 245 N·m (181 lb·ft) @4700 rpm.
Applications:
- 1991-1992 E34 525i/525ix
- 1992 E36 325i/325is
M50TUB20
The M50TUB20 is a technologically upgraded (TU) version of the BMW M50B20, introduced in 1993. The most notable change present is the inclusion of BMW's VANOS variable cam timing system on the intake cam. Power output remains identical; however, there is a slight increase in torque at lower and medium rpms.
Applications:
M50TUB25
The M50TUB25 is a technologically upgraded (TU) version of the BMW M50B25, introduced in 1993. The most notable change present is the inclusion of BMW's VANOS variable cam timing system on the intake cam. Power output remains identical; however, there is a slight increase in torque at lower and medium rpms. Was retired too the m52, a 2.8l version, in 1996.
Applications:
- 1993-1996 E34 525i/525ix
- 1993-1996 E36 325i/325is
S50B30US
The S50B30US was a 3.0 L version, which powered the US-spec E36 M3. Power was 240 hp (179 kW). Unlike the RoW S50, this engine used a regular M50 intake in lieu of the individual throttle body set up and hydraulic valve lifters in lieu of solid ones. The cylinder head and the VANOS system are also different on the US S50 versus the RoW model; again having more in common with the regular M50 than the Euro S50.
Applications:
S50B30
The S50B30 was a special sports-oriented 3.0 L version, which powered the RoW spec E36 M3. Power is 286 hp (210 kW). The S50B30 has a bore of 86 mm and a stroke of 85.8 mm, with a total displacement of 2990 cc. The engine has a maximum permissible speed of 7280 rpm +/-80, and a permissible constant speed of 7000 rpm. It used an ITB intake system with an oversized MAF and a tubular exhaust manifold. The cylinder head was unique and the VANOS system was more advanced than the one used on normal M50s.
Applications:
S50B32
The S50B32 was an evolution version of the S50B30. Power of the 3.2 L version is 321 hp (239 kW). This engine has a bore of 86.4 mm and a stroke of 91.0 mm giving a displacement of 3201 cc. It has a maximum permissible speed of 7600 +/-50 rpm, and a permissible constant speed of 7400 rpm.
Applications:
- 1996-1999 E36 M3
- 1997-2000 M Roadster
- 1998-2000 M Coupe
S54B32
 |
|
| Manufacturer | BMW M GmbH |
|---|---|
| Production | 2001–2008 |
| Predecessor | BMW S50B32 |
| Class | Straight-6 |
| Engine(s) | 3.2 L (3246 cc/132 in³) 252 kW, 365 N·m (269 lb·ft) |
The S54B32 is a high-performance engine used in BMW M vehicles. Its block is made from grey cast iron rather than aluminum to achieve greater rigidity from the same dimensions. It is a 3.2 L (3246 cc) engine; bore is 87 mm (3.4 in) and stroke is 91 mm (3.6 in). Power output is 343 hp (256 kW) at 7900 rpm with 269 ft·lb (365 Nm) of torque at 4900 rpm with an 8000 rpm redline. The US version of this engine required some modifications to meet US emissions standards (such as close-coupled catalytic converters closer to the engine exhaust ports) and thus produced slightly less power at 333 hp (248 kW) and 262 ft·lb (355 Nm). The Z4 using this engine was rated at 330 HP, while the Z3 that used this engine was rated at 315 HP.
The S54 is the final, most powerful evolution of the M50 engine line, incorporating individual throttle bodies, drive-by-wire throttle control, and variable valve timing (VANOS) for both intake and exhaust camshafts.
BMW also produced an even more powerful version of the S54B32, for the limited edition E46 M3 CSL. This engine lacked a conventional mass airflow meter, and BMW installed modified intake and exhaust camshafts, as well as a more efficient air intake system. This version yielded 360 hp (270 kW) at 7900 rpm with 273 ft·lbf (370 N·m) of torque at 4300 rpm.
The S54 won the International Engine of the Year award overall for 2001, and also claimed the "Best New Engine" that year as well as won the 3-4 L category for six straight years in a row from 2001 through 2006. The S54 was also on the Ward's 10 Best Engines list for 2001 through 2004.
Despite its great success and critical acclaim, the S54 was plagued with rod bearing failures in early production. BMW attempted to blame vehicle owners for the failures early on but eventually started replacing rod bearings, oil pumps, and whole engines under warranty. This fault was attributed to a problem with the connecting rod bottom-end bearing shells that were supplied to BMW by a third party that did not meet BMW's specifications. This problem was fully corrected by BMW on engines produced after 06/2003. A recall was issued to retrofit all M3 cars with affected engines to swap to the proper bearing shells. The recall did not include M Roadster or M Coupe cars with affected S54 engines.
BMW has since retired the S54 engine. But it is still used by Wiesmann for their MF3 Roadster.
Applications:
- 2001-2006 E46 M3
- 2001-2002 Z3 M Roadster
- 2001-2002 Z3 M Coupé
- 2006-2008 E85 Z4 M Roadster
- 2006-2008 E86 Z4 M Coupé
- 2002-.... Wiesmann Roadster MF3
Other links
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