BMW M50

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BMW M50 engine
1993 bmw 325is engine.jpg
Overview
Manufacturer BMW, Bayerische Motoren Werke AG
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 which replaced the BMW M20 and was produced from 1990 to 1996.

Compared with its M20 predecessor, the M50 features twin camshafts and 4 valves per cylinder. The M50 uses an iron block with an alloy head.[1]

In September 1992, the M50 was upgraded to the M50TU ("technical update"), which added variable valve timing (called VANOS by BMW).[2]

The E36 M3 was powered by the S50 engine series, which is based on the M50.

Models[edit]

Engine Displacement Power Torque[3] Redline Bore Stroke Year Compression ratio
M50B20 1,991 cc (121 cu in) 110 kW (150 PS; 148 hp) @ 6000 190 N·m (140 lb·ft) @ 4700 6750 80 mm (3.1 in) 66 mm (2.6 in) 1990 10.5:1
M50B20TU 110 kW (150 PS; 148 hp) @ 5900 190 N·m (140 lb·ft) @ 4200 6750 80 mm (3.1 in) 66 mm (2.6 in) 1993 11.0:1
M50B24 2,394 cc (146 cu in) 138 kW (188 PS; 185 hp) @ 5900 235 N·m (173 lb·ft) @ 4700 6550 84 mm (3.3 in) 72 mm (2.8 in) 1991
M50B25 2,494 cc (152 cu in) 141 kW (192 PS; 189 hp) @ 5900 245 N·m (181 lb·ft) @ 4700 6500 84 mm (3.3 in) 75 mm (3.0 in) 1990 10.0:1
M50B25TU 141 kW (192 PS; 189 hp) @ 5900 245 N·m (181 lb·ft) @ 4200 6500 84 mm (3.3 in) 75 mm (3.0 in) 1993 10.5:1
S50B30 2,990 cc (182 cu in) 210 kW (286 PS; 282 hp) @ 7000 320 N·m (236 lb·ft) @ 3600 7280 86 mm (3.4 in) 86 mm (3.4 in) 1992 10.8:1 [4]
S50 (US market) 179 kW (243 PS; 240 hp) @ 6000 305 N·m (225 lb·ft) @ 4250 6500 86 mm (3.4 in) 86 mm (3.4 in) 1993 10.5:1 [4]
S50B32 3,201 cc (195 cu in) 236 kW (321 PS; 316 hp) @ 7400 350 N·m (258 lb·ft) @ 3250 7600 86.4 mm (3.4 in) 91 mm (3.6 in) 1995 11.3:1 [5]

M50B20[edit]

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).[6]

Applications:

M50TUB20[edit]

The M50B20 was updated with variable valve timing (called VANOS by BMW) on the intake camshaft in 1993. Peak torque became available 500 rpm lower, at 4200 rpm.[6]

Applications:

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

M50B24[edit]

This is a 2.4 L engine used in the Thailand market E36 3-series and E34 5-series only. It is based on the 2.5 L M50B25 with a reduced stroke.[citation needed]

M50B25[edit]

The 2,494 cc (152 cu in) M50B25 was introduced with the 1990 525i/525ix . It has an 84 mm (3.3 in) bore and 75 mm (3.0 in) stroke and produces 141 kW (192 PS; 189 hp) at 6000 rpm and 245 N·m (181 lb·ft) at 4700 rpm.[6]

Applications:

M50TUB25[edit]

The M50B25 was updated with variable valve timing (called VANOS by BMW) on the intake camshaft in 1993. Peak torque became available 500 rpm lower, at 4200 rpm.[6]

Applications:

S50[edit]

The S50 is higher 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.

Upgrades over the M50 include:[citation needed]

  • Individual throttle plates for each cylinder
  • Continuously variable "Vanos" valve timing.
  • Lightweight pistons
  • Graphite-coated conrods
  • Larger inlet valves
  • Redesigned equal length exhaust manifolds


S50B30[edit]

The S50B30 is a 2,990 cc (182 cu in) higher output version of the M50 which powered the E36 M3 (except in the USA. Canada had a limited production run of 45 cars with the S50B30 engine). Engine management is provided by a Bosch Motronic M3.3 ECU with a separate "VNC" Vanos control unit providing fully variable single camshaft adjustment on the intake side. It produces 210 kW (282 hp), has a bore of 86 millimetres (3.4 in) and a stroke of 86 millimetres (3.4 in), and a compression ratio of 10.8:1.[7] The limited edition "M3 GT" model from 1995 had different camshafts and a redesigned sump and oil pump, and produced 216 kW (294 PS; 290 hp) .[8]

Applications:

  • 1992-1995 E36 M3 (except for USA)

S50 (US market)[edit]

The E36 M3 for USA is powered by a 3.0L tuned version of the M50 which produced 240 hp (179 kW).[9] This engine was based on the M50TU out of the 325 but was bored out to yield greater displacement and utilized the same cylinder head but with more aggressive cams and valvetrain.[citation needed]

Applications:

S50B32[edit]

In 1995, the 3,201 cc (195 cu in) S50B32 replaced the S50B30 (except in Canada and USA, which used the lower output S52).[10] Engine management is provided by a Siemens MSS50 control unit featuring integrated Vanos control for both the intake and exhaust camshafts. The oil sump is a smaller capacity unit first seen on the M3GT and features a dual pick-up system to lower the risk of oil being forced away from a single pick-up point under cornering. This engine produces 236 kW (321 PS; 316 hp). The compression ratio is 11.3:1, the bore is 86.4 mm (3.4 in) and the stroke is 91 mm (3.6 in).[11]

Applications:

  • 1995-1999 E36 M3 (except Canada and USA)
  • 1997-2001 Z3 M coupe and M roadster (except Canada and USA)

See also[edit]

References[edit]

  1. ^ "The BMW Six Cylinder Guide". AutoSpeed. Retrieved 2012-10-11. 
  2. ^ "BMW M50 engine". usautoparts.net. Retrieved 2012-11-23. 
  3. ^ "Engine Specifications for M50 engines". Retrieved 13 July 2014. 
  4. ^ a b "BMW M3 E36". BMW M Registry. Retrieved 2012-11-23. 
  5. ^ "FAQ E36/8 M coupe". BMW M Registry. Retrieved 2012-11-23. 
  6. ^ a b c d "BMW Heaven Specification Database | Engine specifications for M50 engines". Bmwheaven.com. Retrieved 2012-10-11. 
  7. ^ "BMW M3, 1993 E36 technical specifications 54967". Carfolio.com. 2012-05-16. Retrieved 2012-10-11. 
  8. ^ "FAQ E36 M3 3.0". BMW M Registry. Retrieved 2012-06-03. 
  9. ^ "FAQ E36 M3 3.0". BMW M Registry. Retrieved 2012-10-11. 
  10. ^ "1995-1999 BMW M3 - Used Car Reviews". Motor Trend. Retrieved 2012-10-11. 
  11. ^ "BMW Heaven Specification Database | Engine specifications for Motorsport engines". Bmwheaven.com. Retrieved 2012-10-11.