BMW M50 - Wikipedia

Reciprocating internal combustion engine

BMW M50 engine
Overview
Production	1990–1996
Layout
Configuration	Straight-6
Displacement	1,991 cc (121 cu in)2,394 cc (146 cu in)2,494 cc (152 cu in)
Cylinder bore	80 mm (3.1 in)84 mm (3.3 in)
Piston stroke	66 mm (2.6 in)72 mm (2.8 in)75 mm (3.0 in)
Cylinder block material	Cast iron
Cylinder head material	Aluminium
Valvetrain	DOHC, VVT ("TÜ" versions only)
Combustion
Fuel type	Petrol
Chronology
Predecessor	BMW M20
Successor	BMW M52

The BMW M50 is a straight-6 DOHC petrol engine which was produced from 1990 to 1996. It was released in the E34 520i and 525i, to replace the M20 engine.[1]

In September 1992, the M50 was upgraded to the M50TÜ (Technische Überarbeitung, "technical revision"). This was BMW's first engine to use variable valve timing.[2] Called single VANOS by BMW, the system adjusted the phasing of the intake camshaft.[3]

The M50 began to be phased out following the introduction of the M52 engine in 1994.

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

Design

[edit]

A significant advance over its M20 predecessor, the M50 features dual overhead camshaft (DOHC) with four valves per cylinder (the M20 has a single overhead camshaft with 2 valves per cylinder), coil-on-plug ignition, a knock sensor and a lightweight plastic intake manifold.[4] Both engines use an iron block with an aluminum alloy head.[5] The redline is 6,500 rpm for the M50B25 and 6,750 rpm for the M50B20 (7,000 rpm for S50 models), the same as the final version of the M20.

The location of the oil pan (sump) varies according to the model the M50 is installed in. It is in the front on the E34 5 Series (like the M20),[6] whereas it is in the rear on the E36 3 Series.[7]

Models

[edit]

Engine	Displacement	Power	Torque	Years
M50B20	1,991 cc (121.5 cu in)	110 kW (150 PS; 148 hp) at 6,000 rpm	190 N⋅m (140 lb⋅ft) at 4,700 rpm	1990-1992
M50B20TÜ		110 kW (150 PS; 148 hp) at 5,900 rpm	190 N⋅m (140 lb⋅ft) at 4,200 rpm	1992-1996
M50B24TÜ	2,394 cc (146.1 cu in)	138 kW (188 PS; 185 hp) at 5,900 rpm	240 N⋅m (180 lb⋅ft) at 4,200 rpm
M50B25	2,494 cc (152.2 cu in)	141 kW (192 PS; 189 hp) at 6,000 rpm	245 N⋅m (181 lb⋅ft) at 4,700 rpm	1990-1992
M50B25TÜ		141 kW (192 PS; 189 hp) at 5,900 rpm	250 N⋅m (180 lb⋅ft) at 4,200 rpm	1992-1996
S50B30 (EU)	2,990 cc (182.5 cu in)	210 kW (286 PS; 282 hp) at 7,000 rpm[a]	329 N⋅m (243 lb⋅ft) at 3,500 rpm	1992-1995
S50B30 (US)		240 hp (180 kW; 240 PS) at 6,000 rpm	225 lb⋅ft (305 N⋅m) at 4,250 rpm	1994-1995
S50B30GT		217 kW (295 PS; 291 hp) at 7,100 rpm	323 N⋅m (238 lb⋅ft) at 3,900 rpm	1994-1995
S50B32	3,201 cc (195.3 cu in)	236 kW (321 PS; 316 hp) at 7,400 rpm	350 N⋅m (260 lb⋅ft) at 3,250 rpm	1995-2000

M50B20

[edit]

The 1,991 cc (121.5 cu in) M50B20 was introduced with the 1990 520i. It has a bore of 80 mm (3.15 in), a stroke of 66 mm (2.60 in) and produces 110 kW (150 PS; 148 hp). The compression ratio is 10.5:1.[8]

Applications:

• 1990-1992 E34 520i
• 1991-1995 E36 320i

M50B20TÜ

[edit]

The M50B20 was updated with single VANOS in 1992. Peak torque became available at 4,200 rpm.[8] It produces 110 kW (150 PS; 148 hp) at 5,900 rpm and 190 N⋅m (140 lb⋅ft) at 4,200 rpm. The compression ratio was raised to 11.0:1.

Applications:

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

M50B24TÜ

[edit]

This is a 2,394 cc (146.1 cu in) engine used in the Thailand and Oceanian markets.[9] It is based on the 2,494 cc (2.5 L) M50B25TÜ with the stroke reduced to 72 mm (2.83 in) and produces 138 kW (188 PS; 185 hp) at 5,900 rpm and 240 N⋅m (180 lb⋅ft) at 4,200 rpm. The compression ratio is 10.5:1.

Applications:

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

M50B25

[edit]

The 2,494 cc (152.2 cu in) M50B25 was introduced with the 1990 525i and 525ix. It has a bore of 84 mm (3.31 in), a stroke of 75 mm (2.95 in) and produces 141 kW (192 PS; 189 hp) at 6,000 rpm and 245 N⋅m (181 lb⋅ft) at 4,700 rpm.[8] The compression ratio is 10.0:1.

Applications:

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

M50B25TÜ

[edit]

The M50B25 was updated with single VANOS in 1992, resulting in peak torque becoming available at 4,200 rpm. It produces 141 kW (192 PS; 189 hp) at 5,900 rpm and 250 N⋅m (180 lb⋅ft) at 4,200 rpm.[8] The compression ratio was increased to 10.5:1.

Applications:

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

M50B30TÜ concept

[edit]

This section does not cite any sources. Please help improve this section by adding citations to reliable sources. Unsourced material may be challenged and removed. (September 2021) (Learn how and when to remove this message)

In 1993, BMW Individual created a concept of BMW E34 530iX called Enduro Touring. Only one car was produced, having an up-sized variant of M50B25TÜ engine. Bore and stroke was increased and the total displacement of 3.0 was achieved. The power and torque both increased to 181 kW (246 PS; 243 hp) and 316 N⋅m (233 lb⋅ft) respectively.

S50

[edit] Reciprocating internal combustion engine

BMW S50 engine
Overview
Production	1992–2000[10]
Layout
Configuration	Straight-6
Displacement	2,990 cc (182 cu in)3,201 cc (195 cu in)
Cylinder bore	86 mm (3.4 in)86.4 mm (3.40 in)
Piston stroke	85.8 mm (3.38 in)91 mm (3.6 in)
Cylinder block material	Cast iron
Cylinder head material	Aluminium
Valvetrain	DOHC, with VVT
Combustion
Fuel type	Petrol
Chronology
Predecessor	None
Successor	BMW S54

The S50 is the high performance version of the M50 which was used in the E36 M3, replacing the four-cylinder BMW S14 engine used in the E30 M3. Like the M50, the S50 has an iron block and aluminum head with four valves per cylinder.

In the United States, a less powerful engine called the "S50B30US" was used, which shares more in common with the regular M50 engine than the other S50 versions.

S50B30

[edit]

The S50B30 was used in most countries, except for the United States.[b] The S50B30 produces 210 kW (286 PS; 282 hp), has a bore of 86 mm (3.39 in), a stroke of 85.8 mm (3.38 in) and a compression ratio of 10.8:1.[13][14] The redline is 7,200 rpm. The S50 has an individual throttle body for each cylinder, single-VANOS (variable valve timing on the intake camshaft), Bosch Motronic M3.3 engine management and redesigned intake and exhaust systems.[11][15]

The limited edition "M3 GT" model from 1995 produced 220 kW (299 PS; 295 hp).[11] It had different camshafts and a redesigned sump and oil pump.

Applications:

• 1992-1995 E36 M3 (except for U.S.)

S50B30US

[edit]

In the United States, the 1994-1995 model years of the E36 M3 are powered by the S50B30US, a 2,990 cc (182.5 cu in) engine which produces 179 kW (243 PS; 240 hp).[11][16] This engine is more closely related to the standard M50 engine and has the same compression ratio as the M50B25TÜ,[11] but uses a different camshafts, crankshaft, connecting rods, and pistons. The bore is 86 mm (3.39 in), the stroke is 85.8 mm (3.38 in) and the redline is 7,000 rpm.[17]

The S50B30US motor was created as a compromise to make the E36 M3 a reality in the United States. Unlike in Europe, the E30 M3 was considered a business failure in America. American customers did not see the value proposition of this vehicle compared to a 325i, and due to this, E30 M3s sold poorly in the United States with just over 5,000 units sold. For comparison, the 325i sold just under 350,000 units. Because of this, BMW of North America planned on canning the M brand in the US, and with it any plans to bring the E36 M3 to America. This was until an editor for the BMW Car Club of America, Bob Roehmer, encouraged BMW CCA members to mail BMW of North America letters asking them to bring the car to the United States. This worked, with many BMW CCA members promising to buy an E36 M3 if it was brought to the United States at a reasonable price. To meet this caveat, Erik Wensberg, the manager of the BMW M Brand in North America, decided to remove the European spec S50 motor, and replace it with a M50 motor that was tuned by the BMW M division. This motor would become the S50B30US, and would only be found in American spec E36 M3s. [18]

In 1996, the S50B30US was replaced by the BMW S52 engine (in the United States and Canada only). This motor was a derivative of the M52, and while it maintained the same 240 horsepower as the S50B30US, it gained 11 ft lbs of torque and increased displacement from 3000cc to 3200cc [19]

Applications:

• 1994-1995 E36 M3 (U.S. only)

S50B32

[edit]

In 1995, the S50B32 replaced the S50B30 in world markets.[c] Power output increased to 236 kW (321 PS; 316 hp)[21] and the displacement increased to 3.2 L; 195.3 cu in (3,201 cc), due to an increased stroke of 91 mm (3.58 in) and a slight increase in bore to 86.4 mm (3.40 in).[22]

The S50B32 has double-VANOS (variable valve timing on both camshafts) and a secondary oil pick-up was added.[23] The compression ratio is 11.3:1 and the redline is 7,600 rpm.[24] Engine management is the Siemens MSS50, with 3 knock sensors.

Applications:

• 1995-1999 BMW M3 (E36) (except Canada and the United States)
• 1996-2000 BMW M Coupé and M Roadster (except Canada and the United States)

See also

[edit]

• BMW engines

Notes

[edit]

1. ^ U.S. models were produced from 1993-1995 and were rated at 240 hp (180 kW; 240 PS) at 6,000 rpm and 305 N⋅m (225 lb⋅ft) at 4,250 rpm.
2. ^ In 1993, BMW Canada officially imported 45 M3 coupes with the S50B30 engine.[11][12]
3. ^ United States and Canada received the BMW S52 instead.[20]

References

[edit]

1. ^ "BMW 5 Series E34 History and Characteristics". www.bmwguide.net. 16 February 2015. Retrieved 27 October 2017.
2. ^ "Diagnosing a Failing BMW Vanos System". www.bmwn54tuners.com. 5 December 2017. Retrieved 15 December 2018.
3. ^ "BMW M50 engine". www.usautoparts.net. Archived from the original on 2012-05-12.
4. ^ "BMW M50 M52 M54 Engines". www.unixnerd.demon.co.uk. Archived from the original on 2018-09-27. Retrieved 2015-11-03.
5. ^ "The BMW Six Cylinder Guide". www.autospeed.com. Archived from the original on 2012-03-29. Retrieved 2012-06-24.
6. ^ "5' E34 525i Short Engine". www.realoem.com. Retrieved 28 September 2017.
7. ^ "3' E36 325i Short Engine". www.realoem.com. Retrieved 28 September 2017.
8. ^ a b c d "Engine specifications- M50". www.bmwheaven.com. Archived from the original on January 18, 2013.
9. ^ Hudock, Greg (14 October 2012). BMW E - Series Restoration Bible. Brooklands Books. p. 8-6. ISBN 9781855209701.
10. ^ "BMW S50B32 automotive engine". bmw-grouparchiv.de. Archived from the original on 11 November 2018. Retrieved 18 June 2019.
11. ^ a b c d e "BMW M Registry - FAQ E36 M3 3.0". www.bmwmregistry.com.
12. ^ "1 of 45: 1994 BMW M3 Canadian Edition". www.germancarsforsaleblog.com. 18 August 2016. Retrieved 29 September 2017.
13. ^ "BMW E36 3 Series Coupe M3 Specs". www.ultimatespecs.com. Retrieved 1 October 2017.
14. ^ "1993 BMW M3 E36". www.carfolio.com.
15. ^ "BMW S50 in all its glory". www.drive-my.com. 30 October 2014. Retrieved 15 December 2018.
16. ^ "Engine specifications- S50 B30 US". www.bmwheaven.com.
17. ^ "1994 BMW E36 3 Series Coupe M3 Automatic (US spec)". www.ultimatespecs.com.
18. ^ "The US E36 M3 is the one to have, even without a real M engine". www.hagerty.com. 10 February 2022.
19. ^ "E36 M3 coupe model selection- March 1996 in US spec". www.realoem.com.
20. ^ "1995-1999 BMW M3". www.motortrend.com.
21. ^ "BMW M3 Coupé, 321 PS (E36)". bmw-grouparchiv.de. Archived from the original on 4 November 2018. Retrieved 4 January 2021.
22. ^ "Engine specifications- S50B32 Euro". www.bmwheaven.com.
23. ^ "FAQ E36 M3 3.2". www.bmwmregistry.com. Retrieved 1 October 2017.
24. ^ "BMW M Registry - FAQ E36/8 M coupe". www.bmwmregistry.com.

v t e « previous — BMW automotive petrol engines: 1980s to 2000s — next »

1980s 1990s 2000s 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 Straight-4 <<M10 M40 M43 N40 / N42 N45 / N46>> M12/13 M42 M44 N43>> S14 Straight-6 <<M20 M50 M52 M54 N52>> << M30 N53>> <<M88 / M90 S38 S50 / S52 S54 Straight-6 turbo M102 M106 N54>> N55>> V8 M60 M62 N62>> S62 S65>> V8 turbo N63>> V10 E41/P80 S85>> V12 M70 M73 N73>> S70 V12 turbo N74>>      Production of previous model continues in parallel