View source for BMW M50

{{Infobox automobile engine
| name = BMW M50 engine
| image = 1993 bmw 325is engine.jpg
| production = 1990&ndash;1996
| configuration = [[Straight-six engine|Straight-6]]
| valvetrain = [[DOHC]], <br/> [[variable valve timing|VVT]] ("TÜ" versions only)
| head = Aluminium
| block = Cast iron
| predecessor = [[BMW M20]]
| successor = [[BMW M52]]
| manufacturer = 
| fueltype = [[Petrol]]
| displacement = {{cvt|1991|cc|cuin|0|lk=on}}<br>{{cvt|2394|cc|cuin|0|lk=on}}<br>{{cvt|2494|cc|cuin|0|lk=on}}
| bore = {{cvt|80|mm|abbr=on}}<br>{{cvt|84|mm|abbr=on}}
| stroke = {{cvt|66|mm|abbr=on}}<br>{{cvt|72|mm|abbr=on}}<br>{{cvt|75|mm|abbr=on}}
}}

The [[BMW]] '''M50''' is a [[straight-6]] [[DOHC]] petrol engine which was produced from 1990 to 1996. It was released in the [[BMW 5 Series (E34)|E34]] 520i and 525i, to replace the [[BMW M20|M20]] engine.<ref>{{cite web|title=BMW 5 Series E34 History and Characteristics|url=https://bmwguide.net/bmw-e34-history-and-characteristics/|website=www.bmwguide.net|date=16 February 2015 |accessdate=27 October 2017}}</ref>

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]].<ref name="bmwn54tuners.com">{{cite web |title=Diagnosing a Failing BMW Vanos System |url=https://www.bmwn54tuners.com/diagnosing-a-failing-bmw-vanos-system/ |website=www.bmwn54tuners.com |accessdate=15 December 2018 |date=5 December 2017}}</ref> Called [[VANOS#Single VANOS|single VANOS]] by BMW, the system adjusted the phasing of the intake [[camshaft]].<ref>{{cite web|url=http://www.usautoparts.net/bmw/engines/m50.htm |title=BMW M50 engine |website=www.usautoparts.net |url-status=dead |archiveurl=https://web.archive.org/web/20120512014705/http://www.usautoparts.net/bmw/engines/m50.htm |archivedate=2012-05-12 }}</ref>

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

The [[BMW M3|E36 M3]] is powered by the [[#S50|S50]] engine series, which is a high output version of the M50.

== Design ==
[[File:BMW E34 Touring Lazurblau 1993 4.jpg|thumb|right|Initial version of the M50 (prior to 1992 Technical Update)]]
A significant advance over its [[BMW M20|M20]] predecessor, the M50 features [[dual overhead camshaft]] (DOHC) with [[Multi-valve#Four valves|four valves per cylinder]] (the M20 has a [[single overhead camshaft]] with 2 valves per cylinder), [[Distributor#Direct ignition|coil-on-plug ignition]], a [[Engine knocking#Knock detection|knock sensor]] and a lightweight plastic [[intake manifold]].<ref>{{cite web|title=BMW M50 M52 M54 Engines|url=http://www.unixnerd.demon.co.uk/m50.html|website=www.unixnerd.demon.co.uk|access-date=2015-11-03|archive-date=2018-09-27|archive-url=https://web.archive.org/web/20180927162926/http://www.unixnerd.demon.co.uk/m50.html|url-status=dead}}</ref> Both engines use an iron block with an aluminum alloy head.<ref>{{cite web |url=http://autospeed.com/cms/title_The-BMW-Six-Cylinder-Guide/A_2948/article.html |title=The BMW Six Cylinder Guide |website=www.autospeed.com |access-date=2012-06-24 |archive-url=https://web.archive.org/web/20120329195446/http://autospeed.com/cms/title_The-BMW-Six-Cylinder-Guide/A_2948/article.html |archive-date=2012-03-29 |url-status=dead }}</ref> The redline is 6,500&nbsp;rpm for the M50B25 and 6,750&nbsp;rpm for the M50B20 (7,000&nbsp;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 [[BMW 5 Series (E34)|E34 5 Series]] (like the M20),<ref>{{cite web|title=5' E34 525i Short Engine|url=http://www.realoem.com/bmw/en/showparts?id=HD61-EUR-01-1995-E34-BMW-525i&diagId=11_0031|website=www.realoem.com|accessdate=28 September 2017}}</ref> whereas it is in the rear on the [[BMW 3 Series (E36)|E36 3 Series]].<ref>{{cite web|title=3' E36 325i Short Engine|url=http://www.realoem.com/bmw/en/showparts?id=CB31-EUR-03-1990-E36-BMW-325i&diagId=11_1295|website=www.realoem.com|accessdate=28 September 2017}}</ref>

== Models ==
{|class="wikitable sortable"
|-
!Engine!!Displacement!!Power!!Torque!! Years
|-
!M50B20
|rowspan=2|{{cvt|1991|cc|cuin|1}}|| {{cvt|110|kW|PS hp|0}} <br/> at 6,000&nbsp;rpm || {{cvt|190|Nm|lb·ft}} <br/> at 4,700&nbsp;rpm || 1990-1992
|-
!M50B20TÜ
| {{cvt|110|kW|PS hp|0}}<br/> at 5,900&nbsp;rpm || {{cvt|190|Nm|lb·ft}} <br/> at 4,200&nbsp;rpm || rowspan="2" | 1992-1996
|-
!M50B24TÜ
|{{cvt|2394|cc|cuin|1}}|| {{cvt|138|kW|PS hp|0}}<br/> at 5,900&nbsp;rpm || {{cvt|240|Nm|lb·ft}} <br/> at 4,200&nbsp;rpm
|-
!M50B25
|rowspan=2|{{cvt|2494|cc|cuin|1}}|| {{cvt|141|kW|PS hp|0}}<br/> at 6,000&nbsp;rpm || {{cvt|245|Nm|lb·ft}} <br/> at 4,700&nbsp;rpm || 1990-1992
|-
!M50B25TÜ
| {{cvt|141|kW|PS hp|0}}<br/> at 5,900&nbsp;rpm || {{cvt|250|Nm|lb·ft}} <br/> at 4,200&nbsp;rpm || 1992-1996
|-
!S50B30 (EU)
| rowspan="3" | {{cvt|2990|cc|cuin|1}}|| {{cvt|210|kW|PS hp|0}}<br/> at 7,000&nbsp;rpm{{efn|U.S. models were produced from 1993-1995 and were rated at {{cvt|240|hp|kW PS}} at 6,000&nbsp;rpm and {{cvt|305|Nm|lb·ft}} at 4,250&nbsp;rpm.}} || {{cvt|329|Nm|lbft|0}}<br/> at 3,500&nbsp;rpm || 1992-1995
|-
!S50B30 (US)
| {{cvt|240|hp|kW PS}}<br/> at 6,000&nbsp;rpm || {{cvt|225|lbft|Nm|0}}<br/> at 4,250&nbsp;rpm || 1994-1995
|-
!S50B30GT
| {{cvt|217|kW|PS hp|0}}<br/> at 7,100&nbsp;rpm || {{cvt|323|Nm|lbft|0}} <br/> at 3,900&nbsp;rpm || 1994-1995
|-
!S50B32 
| {{cvt|3201|cc|cuin|1}}|| {{cvt|236|kW|PS hp|0}}<br/> at 7,400&nbsp;rpm || {{cvt|350|Nm|lb·ft}} <br/> at 3,250&nbsp;rpm || 1995-2000
|}

=== M50B20 ===
[[File:BMW M50 engine in BMW-Museum in Munich, Bayern.JPG|thumb|M50 engine in BMW Museum]]
The {{cvt|1991|cc|cuin|1}} M50B20 was introduced with the 1990 [[BMW E34|520i]]. It has a [[Bore (engine)|bore]] of {{cvt|80|mm|in|2|abbr=on}}, a [[Stroke_(engine)#Stroke_length|stroke]] of {{cvt|66|mm|in|2|abbr=on}} and produces {{cvt|110|kW|PS hp|0}}. The compression ratio is 10.5:1.<ref name="bmwheaven">{{cite web|url=http://www.bmwheaven.com/database/engine.php?type=M50 |archive-url=https://archive.today/20130118090934/http://www.bmwheaven.com/database/engine.php?type=M50 |url-status=dead |archive-date=January 18, 2013 |title=Engine specifications- M50 |website=www.bmwheaven.com}}</ref>

Applications:
* 1990-1992 [[BMW E34|E34]] 520i
* 1991-1995 [[BMW E36|E36]] 320i

=== {{anchor|M50B20TU|M50B20TÜ}} M50B20TÜ ===
The M50B20 was updated with single VANOS in 1992. Peak torque became available at 4,200 rpm.<ref name=bmwheaven /> It produces  {{cvt|110|kW|PS hp|0}} at 5,900 rpm and {{cvt|190|Nm|lb·ft}} at 4,200 rpm. The compression ratio was raised to 11.0:1.

Applications:
* 1992-1994 [[BMW E36|E36]] 320i
* 1992-1996 [[BMW E34|E34]] 520i

=== {{anchor|M50B24TU|M50B24TÜ}} M50B24TÜ ===
This is a {{cvt|2394|cc|cuin|1}} engine used in the Thailand and Oceanian markets.<ref>{{cite book|last1=Hudock|first1=Greg|title=BMW E - Series Restoration Bible|date=14 October 2012|publisher=Brooklands Books|isbn=9781855209701|page=8-6|url=https://books.google.com/books?id=Wm6hFEwj6CsC&dq=bmw%20m50b24&pg=SA8-PA6}}</ref> It is based on the {{cvt|2494|cc|L|1}} M50B25TÜ with the [[Stroke (engine)|stroke]] reduced to {{cvt|72|mm|in|2|abbr=on}} and produces {{cvt|138|kW|PS hp|0}} at 5,900 rpm and {{cvt|240|Nm|lb·ft}} at 4,200 rpm. The compression ratio is 10.5:1.

Applications:
* 1993-1995 [[BMW E36|E36]] 325iA/2.4
* 1992-1996 [[BMW E34|E34]] 525iA/2.4

=== M50B25 ===
The {{cvt|2494|cc|cuin|1}} M50B25 was introduced with the 1990 525i and 525ix. It has a bore of {{cvt|84|mm|in|2|abbr=on}}, a stroke of {{cvt|75|mm|in|2|abbr=on}} and produces {{cvt|141|kW|PS hp|0}} at 6,000 rpm and {{cvt|245|Nm|lb·ft}} at 4,700 rpm.<ref name=bmwheaven /> The compression ratio is 10.0:1.

Applications:
* 1990-1992 [[BMW E34|E34]] 525i, 525ix
* 1991-1992 [[BMW E36|E36]] 325i, 325is

=== {{anchor|M50B25TU|M50B25TÜ}} M50B25TÜ ===
The M50B25 was updated with single VANOS in 1992, resulting in peak torque becoming available at 4,200 rpm. It produces {{cvt|141|kW|PS hp|0}} at 5,900 rpm and {{cvt|250|Nm|lb·ft}} at 4,200 rpm.<ref name=bmwheaven /> The compression ratio was increased to 10.5:1.

Applications:
* 1993-1995 [[BMW E36|E36]] 325i, 325is
* 1992-1996 [[BMW E34|E34]] 525i, 525ix

=== M50B30TÜ concept ===
{{unreferenced section|date=September 2021}}
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 {{cvt|181|kW|PS hp|0}} and {{cvt|316|Nm|lb·ft}} respectively.

== S50 ==
{{Infobox automobile engine
|name=BMW S50 engine
|image=BMW M3 Evo Coupe E36 - Flickr - The Car Spy (5).jpg
|production=1992&ndash;2000<ref>{{cite web |title=BMW S50B32 automotive engine |url=https://bmw-grouparchiv.de/research/detail/index.xhtml?id=3943301 |website=bmw-grouparchiv.de |accessdate=18 June 2019 |archive-date=11 November 2018 |archive-url=https://web.archive.org/web/20181111055633/https://bmw-grouparchiv.de/research/detail/index.xhtml?id=3943301 |url-status=dead }}</ref>
|configuration= [[Straight-six engine|Straight-6]]
|valvetrain =[[Overhead_camshaft#Dual_overhead_camshaft|DOHC]], with [[variable valve timing|VVT]]
|head       =Aluminium
|block      =Cast iron
|predecessor= None
|successor=[[BMW M54#S54|BMW S54]]
|fueltype=[[Petrol engine|Petrol]]
|displacement={{cvt|2990|cc|cuin|0|lk=on}}<br>{{cvt|3201|cc|cuin|0|lk=on}}
| bore = {{cvt|86|mm|abbr=on}}<br>{{cvt|86.4|mm|abbr=on}}
| stroke = {{cvt|85.8|mm|abbr=on}}<br>{{cvt|91|mm|abbr=on}}
}}
The S50 is the high performance version of the M50 which was used in the [[BMW M3#E36 M3|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 ===
The S50B30 was used in most countries, except for the United States.{{efn|In 1993, BMW Canada officially imported 45 M3 coupes with the S50B30 engine.<ref name=mregistry-e36 /><ref>{{cite web|title=1 of 45: 1994 BMW M3 Canadian Edition|url=http://germancarsforsaleblog.com/1-of-45-1994-bmw-m3-canadian-edition/|website=www.germancarsforsaleblog.com|date=18 August 2016 |accessdate=29 September 2017}}</ref>}}  The S50B30 produces {{cvt|210|kW|PS hp|0}}, has a bore of {{cvt|86|mm|in|2}}, a stroke of {{cvt|85.8|mm|in|2}} and a compression ratio of 10.8:1.<ref>{{cite web|title=BMW E36 3 Series Coupe M3 Specs|url=https://www.ultimatespecs.com/car-specs/BMW/154/BMW-E36-3-Series-Coupe-M3.html|website=www.ultimatespecs.com|accessdate=1 October 2017}}</ref><ref>{{cite web|title=1993 BMW M3 E36|url=http://www.carfolio.com/specifications/models/car/?car=54967|website=www.carfolio.com}}</ref> The redline is 7,200&nbsp;rpm. The S50 has an individual [[Throttle#Throttle body|throttle body]] for each cylinder, [[VANOS#Single_VANOS|single-VANOS]] (variable valve timing on the intake camshaft), [[Motronic#Motronic_3.x|Bosch Motronic M3.3]] engine management and redesigned intake and exhaust systems.<ref name="mregistry-e36"/><ref name="drive-my.com">{{cite web |title=BMW S50 in all its glory |url=https://drive-my.com/en/tech/item/1965-bmw-s50-in-all-its-glory.html |website=www.drive-my.com |date=30 October 2014 |accessdate=15 December 2018 |language=en-gb}}</ref>

The limited edition "M3 GT" model from 1995 produced {{cvt|220|kW|PS hp|0}}.<ref name=mregistry-e36>{{cite web|title=BMW M Registry - FAQ E36 M3 3.0|url=http://www.bmwmregistry.com/model_faq.php?id=14|website=www.bmwmregistry.com}}</ref> It had different [[camshaft]]s and a redesigned sump and oil pump.

Applications:
* 1992-1995 [[BMW M3#E36 M3|E36 M3]] (except for U.S.)

=== S50B30US ===
In the United States, the 1994-1995 model years of the [[BMW M3#E36 M3|E36 M3]] are powered by the S50B30US, a {{cvt|2990|cc|cuin|1|abbr=on}} engine which produces {{cvt|179|kW|PS hp|0}}.<ref name=mregistry-e36 /><ref>{{cite web|title=Engine specifications- S50 B30 US|url=http://www.bmwheaven.com/database/engine.php?type=Motorsport#/222|website=www.bmwheaven.com}}</ref> This engine is more closely related to the standard M50 engine and has the same compression ratio as the M50B25TÜ,<ref name=mregistry-e36 /> but uses a different camshafts, crankshaft, connecting rods, and pistons. The bore is {{cvt|86|mm|in|2}}, the stroke is {{cvt|85.8|mm|in|2}} and the redline is 7,000&nbsp;rpm.<ref>{{cite web|title=1994 BMW E36 3 Series Coupe M3 Automatic (US spec)|url=http://www.ultimatespecs.com/car-specs/BMW/14580/BMW-E36-3-Series-Coupe-M3-Automatic-%28US-spec%29.html|website=www.ultimatespecs.com}}</ref>

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. <ref>{{cite web| title= The US E36 M3 is the one to have, even without a real M engine|url=https://www.youtube.com/watch?v=Xatzi2Whnjo|website=www.hagerty.com | date=10 February 2022 }}</ref>

In 1996, the S50B30US was replaced by the [[BMW M52#S52|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 <ref>{{cite web|title=E36 M3 coupe model selection- March 1996 in US spec|url=http://www.realoem.com/bmw/enUS/select?product=P&archive=1&series=E36&body=Cou&model=M3&market=USA&prod=19960300&engine=S52|website=www.realoem.com}}</ref>

Applications:
* 1994-1995 [[BMW M3#E36 M3|E36 M3]]  (U.S. only)

=== S50B32 ===
In 1995, the S50B32 replaced the S50B30 in world markets.{{efn|United States and Canada received the [[BMW M52#S52|BMW S52]] instead.<ref>{{cite web|title=1995-1999 BMW M3|url=http://www.motortrend.com/buyersguide/preowned/112_0302_1995_1999_bmw_m3/|website=www.motortrend.com}}</ref>}} Power output increased to {{cvt|236|kW|PS hp|0}}<ref>{{cite web |title=BMW M3 Coupé, 321 PS (E36) |url=https://bmw-grouparchiv.de/research/detail/index.xhtml?id=3931554 |website=bmw-grouparchiv.de |access-date=4 January 2021 |archive-date=4 November 2018 |archive-url=https://web.archive.org/web/20181104035951/https://bmw-grouparchiv.de/research/detail/index.xhtml?id=3931554 |url-status=dead }}</ref> and the displacement increased to {{cvt|3201|cc|L cuin|1|order=flip}}, due to an increased stroke of {{cvt|91|mm|in|2|abbr=on}} and a slight increase in bore to {{cvt|86.4|mm|in|abbr=on}}.<ref>{{cite web|title=Engine specifications- S50B32 Euro|url=http://www.bmwheaven.com/database/engine.php?type=Motorsport#/166|website=www.bmwheaven.com}}</ref>

The S50B32 has double-VANOS (variable valve timing on both camshafts) and a secondary oil pick-up was added.<ref>{{cite web|title=FAQ E36 M3 3.2|url=http://www.bmwmregistry.com/model_faq.php?id=15|website=www.bmwmregistry.com|accessdate=1 October 2017}}</ref> The compression ratio is 11.3:1 and the redline is 7,600&nbsp;rpm.<ref>{{cite web|title=BMW M Registry - FAQ E36/8 M coupe|url=http://www.bmwmregistry.com/model_faq.php?id=17|website=www.bmwmregistry.com}}</ref> Engine management is the Siemens MSS50, with 3 knock sensors.

Applications:
* 1995-1999 [[BMW M3#E36 M3|BMW M3 (E36)]] (except Canada and the United States)
* 1996-2000 [[BMW M Coupé and Roadster#E36/8|BMW M Coupé and M Roadster]] (except Canada and the United States)

== See also ==
* [[BMW engines]]

== Notes ==
{{notelist}}

== References ==
{{Reflist|30em}}

{{BMW automotive petrol engines: 1980s to 2000s}}

[[Category:BMW engines|M50]]
[[Category:Straight-six engines]]
[[Category:Gasoline engines by model]]