View source for BMW M20

{{Infobox automobile engine
|image=M20B25.jpg
|name=BMW M20 engine
|production=1977&ndash;1993
|configuration= [[Straight-six engine|Straight-6]]
|displacement={{convert|1991|cc|L|1|order=flip|abbr=on}}<br/>{{convert|2316|cc|L|1|order=flip|abbr=on}}<br/>{{convert|2494|cc|L|1|order=flip|abbr=on}}<br/>{{convert|2693|cc|L|1|order=flip|abbr=on}}
| bore = {{convert|80|mm|in|2|abbr=on}}<br/>{{convert|84|mm|in|2|abbr=on}}
| stroke = {{convert|66|mm|in|2|abbr=on}}<br/>{{convert|75|mm|in|2|abbr=on}}<br/>{{convert|76.8|mm|in|2|abbr=on}}<br/>{{convert|81|mm|in|2|abbr=on}}
|valvetrain= [[Overhead camshaft#Single overhead camshaft|SOHC]]
|fueltype= [[Petrol engine|Petrol]]
|block= Cast iron
|head= Aluminium
|predecessor=None
|successor=[[BMW M50]]
}}

The '''BMW M20''' is a SOHC straight-six petrol engine which was produced from 1977 to 1993. It was introduced eight years after the larger [[BMW M30]] straight-six engine, which remained in production alongside the M20.<ref>{{cite web|title=BMW M30|url=https://www.bmw-tech.org/wiki/BMW_M30|website=www.bmw-tech.org|accessdate=2 December 2017}}</ref>

The first cars to use the M20 were the [[BMW 5 Series (E12)|E12 5 Series]] and the [[BMW 3 Series (E21)|E21 3 Series]]. The initial M20 model had a displacement of {{convert|2.0|L|cuin|0|abbr=on}}, with later versions having displacements of up to {{convert|2.7|L|cuin|0|abbr=on}}.<ref>{{cite web|title=Engine Of The Day: BMW M20|url=https://jalopnik.com/5348352/engine-of-the-day-bmw-m20|website=www.jalopnik.com|date=29 August 2009 |accessdate=18 September 2017}}</ref>

The M20 began to be phased out following the introduction of the [[BMW M50|M50]] engine in 1990. The final M20 engines were fitted to the [[BMW 3 Series (E30)|E30 3 Series]] wagon (estate) and convertible model built in April 1993.<ref>{{cite web|url=https://www.autoevolution.com/cars/bmw-3-series-touring-e30-1986.html|title=BMW 3 Series Touring (E30) (1988 - 1993)|work=autoevolution}}</ref>

The M20 was the basis for the [[BMW M21]] diesel engine.<ref>{{cite web |url=https://www.usautoparts.net/bmw/engines/m21.htm |title=Archived copy |accessdate=2012-06-05 |url-status=dead |archiveurl=https://web.archive.org/web/20120105003459/http://www.usautoparts.net/bmw/engines/m21.htm |archivedate=2012-01-05 }}</ref> It is also loosely related to the [[BMW M70]] V12 petrol engine.

== History ==
By the 1970s, BMW felt the need for a six-cylinder engine smaller than the [[BMW M30]], to use in the 3 Series and 5 Series.<ref>{{cite book|last1=Lewin|first1=Tony|title=The BMW Century|date=2016|publisher=Motorbooks |isbn=978-0-7603-5017-1}}</ref>{{refpage|page=92}} The resulting M20 had a displacement of {{convert|2.0|L|cuin|0|abbr=on}}, BMW's smallest straight-six engine of its day. BMW presented the M20 engine at the [[Internationale Automobilausstellung|1977 IAA]] as a 90&nbsp;kW 2.0-litre Solex 4A1 [[Carburettor|carburetted]] version, and as a 105&nbsp;kW 2.3-litre K-Jetronic [[Multi-point injection|multi-point injected]] version.<ref>BMW AG (ed.): ''[https://bmw-grouparchiv.de/research/media/b758ee3b-59b1-4046-8a97-8355940ade0d/web IAA Frankfurt/Main 15.9. bis 25.9.1977]'', p. 5, retrieved 17 September 2021</ref> Later versions had displacements up to {{convert|2.7|L|cuin|0|abbr=on}}. The M20 was used in the [[BMW 5 Series (E12)|E12 5 Series]], [[BMW 3 Series (E21)|E21 3 Series]], [[BMW 5 Series (E28)|E28 5 Series]], [[BMW 3 Series (E30)|E30 3 Series]] and [[BMW 5 Series (E34)|E34 5 Series]].

Early versions of the M20 were sometimes referred to as the "M60",<ref>{{cite web|url=https://www.bmwccbc.org/resources/index.html|title=Useful info and resources|publisher=BMW Car Club of BC|url-status=dead|archiveurl=https://web.archive.org/web/20120613171917/http://www.bmwccbc.org/resources/index.html|archivedate=2012-06-13}}</ref><ref>{{cite web|url=https://www.unixnerd.demon.co.uk/m20.html|title=The UnixNerd's Domain - BMW M20 Six Cylinder Engines|author=John G.Burns|publisher=|access-date=2021-02-01|archive-date=2020-02-20|archive-url=https://web.archive.org/web/20200220010508/http://www.unixnerd.demon.co.uk/m20.html|url-status=dead}}</ref> although the ''M60'' designation has since been re-used for a [[BMW M60|V8 engine produced from 1992 to 1996]].

== Design ==
As per the M30, the M20 has an iron block, aluminium head and a SOHC valvetrain with 2 valves per cylinder.<ref>{{cite web|title=BMW M20B20 Engine|url=https://mywikimotors.com/m20b20/|website=www.mywikimotors.com|accessdate=18 September 2017|archive-url=https://web.archive.org/web/20170915064709/http://mywikimotors.com/m20b20/|archive-date=2017-09-15|url-status=dead}}</ref> It has a traditional rocker arm design and no hydraulic tappets.<ref>Hans-Rüdiger Etzold: So wird’s gemacht (volume 68): BMW 5er Reihe 9/72 bis 7/81 (TYP E12), BMW 5er Reihe 7/81 bis 8/87 (TYP E28), Delius Klasing, Bielefeld, 1990, ISBN 978-3-7688-0666-4</ref> The major differences to the M30 are:
* A [[Timing belt (camshaft)|timing belt]] rather than a timing chain<ref>{{cite web|title=M20 6-cylinder engine|url=https://www.usautoparts.net/bmw/engines/m20.htm|website=www.usautoparts.net |url-status=dead |archiveurl=https://web.archive.org/web/20140502043709/http://www.usautoparts.net/bmw/engines/m20.htm|archivedate=2 May 2014}}</ref>
* Bore spacing of {{convert|91|mm|in|abbr=on}}, rather than {{Convert|100|mm|in|abbr=on}}<ref>{{cite web|url=https://www.usautoparts.net/bmw/engines/m50.htm |title=M50 Engine |url-status=dead |archiveurl=https://web.archive.org/web/20120512014705/http://www.usautoparts.net/bmw/engines/m50.htm |archivedate=12 May 2012 }}</ref>
* Slant angle of 20 degrees, compared with 30 degrees for the M30.<ref>{{cite web|title=M50 Engine Technical Information (E36)|url=https://bmw3series.johnavis.com/blog/654/m50-engine-e36/|website=www.johnavis.com|accessdate=18 September 2017|archive-url=https://web.archive.org/web/20170917212442/http://bmw3series.johnavis.com/blog/654/m50-engine-e36|archive-date=2017-09-17|url-status=dead}}</ref>

{{gallery
|mode=packed |height=150 |align=center
| File: BMW M20 Engine.JPG
  | M20 engine- exhaust side
| File: BMW M20 engine in BMW-Museum in Munich, Bayern.JPG
  | M20 engine- intake side
| File:M20B25 block.jpg
  |M20 engine- block
}}

==Models==
{|class="wikitable sortable"
!Version!!Displacement!!Power!!Torque!! Years !! Notes
|-
!rowspan=4| [[#M20B20|M20B20]]
|rowspan=4|{{convert|1991|cc|cuin|1|abbr=on}} || {{cvt|90|kW|PS bhp|0}}<br/> at 6,000&nbsp;rpm<ref name="1977 IAA">{{cite web |title=BMW Presse: 47. IAA Frankfurt 1977 |url=https://bmw-grouparchiv.de/research/detail/index.xhtml?id=3212481 |website=bmw-grouparchiv.de |access-date=18 September 2021 |archive-date=18 September 2021 |archive-url=https://web.archive.org/web/20210918052944/https://bmw-grouparchiv.de/research/detail/index.xhtml?id=3212481 |url-status=dead }}</ref> ||{{convert|163|Nm|lbft|0|abbr=on}} <br/> at 4,000&nbsp;rpm || 1977-1982 || Austrian models rated at {{cvt|88|kW|PS|0}}<ref>{{cite web |title=Betriebsanleitung, Serviceheft 518, 520i, 525e, 525i, 528i, 535i, M535i, 524td |url=https://bmw-grouparchiv.de/research/detail/index.xhtml?id=3058985 |website=bmw-grouparchiv.de |access-date=18 September 2021 |date=August 1985 |archive-date=20 July 2022 |archive-url=https://web.archive.org/web/20220720072712/https://bmw-grouparchiv.de/research/detail/index.xhtml?id=3058985 |url-status=dead }}</ref>
|-
|rowspan=2| {{cvt|92|kW|PS bhp|0}} <br/> at 5,800&nbsp;rpm || {{convert|170|Nm|lbft|0|abbr=on}} <br/> at 4,000 rpm ||1982-1984 ||
|-
| {{convert|174|Nm|lbft|0|abbr=on}} <br/> at 4,000 rpm ||1984-1987 ||
|-
|{{cvt|95|kW|PS bhp|0}} <br/> at 6,000 rpm || {{convert|164|Nm|lbft|0|abbr=on}} <br/> at 4,300 rpm ||1986-1992 ||
|-
!rowspan=3|[[#M20B23|M20B23]]
|rowspan=3| {{convert|2316|cc|cuin|1|abbr=on}} ||{{cvt|105|kW|PS bhp|0}} <br/> at 5,300 rpm<ref name="1977 IAA"/> ||{{convert|190|Nm|lbft|0|abbr=on}} <br/> at 4,500 rpm ||1977-1982 ||
|-
|{{cvt|102|kW|PS bhp|0}}<br/> at 5,300 rpm || rowspan=2 | {{convert|205|Nm|lbft|0|abbr=on}} <br/> at 4,000 rpm ||1982-1983 ||
|-
|{{cvt|110|kW|PS bhp|0}}<br/> at 6,000 rpm || 1983-1987 ||
|-
!rowspan=2|[[#M20B25|M20B25]]
|rowspan=2| {{convert|2494|cc|cuin|1|abbr=on}} || {{cvt|126|kW|PS bhp|0}}<br/> at 5,800 rpm ||{{convert|226|Nm|lbft|0|abbr=on}} <br/> at 4,000 rpm ||1985-1990 ||
|-
|{{cvt|125|kW|PS bhp|0}}<br/> at 5,800 rpm ||{{convert|226|Nm|lbft|0|abbr=on}} <br/> at 4,300 rpm ||1987-1992 || Catalyzed
|-
!rowspan=3|[[#M20B27|M20B27]] 
|rowspan=3| {{convert|2693|cc|cuin|1|abbr=on}} || {{cvt|92|kW|PS bhp|0}}<br/> at 4,250 rpm || {{convert|240|Nm|lbft|0|abbr=on}} <br/> at 3,250 rpm ||1982-1985 || US models rated at {{cvt|121|hp|kW|0|order=flip}}

|-
| {{cvt|90|kW|PS bhp|0}}<br/> at 4,250 rpm || {{convert|230|Nm|lbft|0|abbr=on}} <br/> at 3,250 rpm ||1985-1987 || Austrian models rated at {{cvt|88|kW|PS|0}}<ref>{{cite web |title=Zusatzbetriebsanleitung 525e |url=https://bmw-grouparchiv.de/research/detail/index.xhtml?id=3275119 |website=bmw-grouparchiv.de |access-date=19 September 2021 |language=de |page=6 |archive-date=18 September 2021 |archive-url=https://web.archive.org/web/20210918162009/https://bmw-grouparchiv.de/research/detail/index.xhtml?id=3275119 |url-status=dead }}</ref><ref>{{cite web |title=BETRIEBSANLEITUNG 316, 318i, 320i, 325e, 325i, 324d |url=https://bmw-grouparchiv.de/research/detail/index.xhtml?id=3056406 |website=bmw-grouparchiv.de |access-date=19 September 2021 |page=150 |language=German |archive-date=19 September 2021 |archive-url=https://web.archive.org/web/20210919065416/https://bmw-grouparchiv.de/research/detail/index.xhtml?id=3056406 |url-status=dead }}</ref>
|-
|{{cvt|95|kW|PS bhp|0}}<br/> at 4,250 rpm || {{convert|240|Nm|lbft|0|abbr=on}} <br/> at 3,250 rpm ||1985-1988 ||
|}

{{notelist}}
=== M20B20 ===
[[File:BMW e21 engine.JPG|thumb|Early M20 engine with K-Jetronic]]
The first models to use the M20 were the E12 520/6 and the E21 320/6, which used a {{convert|1991|cc|cuin|0|abbr=on}} version known as the ''M20B20VE'' or ''M60/2''.<ref name="carfolio_520">{{cite web|url=https://www.carfolio.com/specifications/models/car/?car=119361|title=1977 BMW 520|publisher=}}</ref><ref>{{cite web |url=https://www.specs4bmw.com/e21/3-series/sedan |title=BMW E21 3-series Sedan specs &#124; Specs4BMW.com |accessdate=2015-12-21 |url-status=dead |archiveurl=https://web.archive.org/web/20150627125125/http://www.specs4bmw.com/e21/3-series/sedan |archivedate=2015-06-27 }}</ref> This engine uses a [[bore (engine)|bore]] of {{Convert|80|mm|in|2|abbr=on}} and a [[stroke (engine)|stroke]] of {{Convert|66|mm|in|2|abbr=on}}.<ref name="carfolio_520" /> A [[Solex Carburetor|Solex]] 4A1 four-barrel carburetor was used in the M20B20VE ("VE" is for ''vergaser''- "carburettor" in German),<ref name="WC81">{{Cite book | title = World Cars 1981 | publisher = The Automobile Club of Italy/Herald Books | editor-last = Lösch | editor-first = Annamaria | location = Pelham, NY | page = 107 | year = 1981 | isbn = 0-910714-13-4 }}</ref> and it has a compression ratio of 9.2:1 and a redline of 6,400&nbsp;rpm.

The M20 first became fuel-injected in 1981,<ref>{{cite web|url=https://www.automobile-catalog.com/car/1982/262835/bmw_520i_4-speed.html|title=1982 BMW 520i 4-speed (for Europe) specs review|work=www.automobile-catalog.com}}{{Dead link|date=July 2025 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> with [[Jetronic#K-Jetronic (1973–1994)|Bosch K-Jetronic]] used in a {{convert|92|kW|0|abbr=on}} version called the ''M20B20KE''.<ref>{{cite journal |title=Automobil Revue |date=1983 |page=205}}</ref> The compression ratio was raised to 9.9:1.

In September 1982 (coinciding with the release of the E30 3&nbsp;Series), the fuel injection was updated to [[Jetronic#LE1-Jetronic, LE2-Jetronic, LE3-Jetronic (1981–1991)|LE-Jetronic]] with a redline of 6,200&nbsp;rpm. Other upgrades included a larger port (known as "731") cylinder head, a lighter block and new manifolds.{{citation needed|date=February 2019}} The "M60" designation was dropped and this version was known as the ''M20B20LE''.<ref name="AR87">{{cite book | title = Automobil Revue 1987 | editor-last = Büschi | editor-first = Hans-Ulrich | publisher = Hallwag AG | location = Berne, Switzerland | language = German, French | pages = 184–186 | volume = 82 |date=March 5, 1987 | isbn = 3-444-00458-3 }}</ref>

In 1987, the M20B20 was again revised with the addition of [[Motronic|Bosch Motronic]] engine management, a catalytic converter and a compression ratio of 8.8:1.<ref name="e30club">{{cite web|url=https://www.e30club.com/bmw-e30|archive-url=https://web.archive.org/web/20111126124748/http://www.e30club.com/bmw-e30|url-status=usurped|archive-date=2011-11-26|title=BMW e30 - BMW e30 Club}}</ref><ref name="AR87"/>

The M20B20 was not sold in the United States, but was available in the E30 (320i) in Canada.

Applications:
* 1977&ndash;1981 [[BMW E12|E12 5 Series]] 520/6 (carburettor)
* 1977&ndash;1982 [[BMW E21|E21 3 Series]] 320/6 (carburettor)
* 1981&ndash;1982 [[BMW E28|E28 5 Series]] 520i (K-Jetronic)<ref>{{cite web|title=5' E28 520i FUEL INJECTION K-JETRONIC|url=https://www.realoem.com/bmw/en/showparts?id=4071-EUR-07-1981-E28-BMW-520i&diagId=13_0150|website=www.realoem.com|accessdate=21 September 2017}}</ref>
* 1982&ndash;1984 [[BMW E28|E28 5 Series]] 520i ([[Jetronic#L-Jetronic (1974–1989)|L-Jetronic]])<ref>{{cite web|title=5' E28 520i Control unit L-jetronic|url=https://www.realoem.com/bmw/en/showparts?id=4051-EUR-01-1983-E28-BMW-520i&diagId=13_0241|website=www.realoem.com|accessdate=21 September 2017}}</ref>
* 1982&ndash;1984 [[BMW E30|E30 3 Series]] 320i (L-Jetronic)
* 1984&ndash;1987 [[BMW E28|E28 5 Series]] 520i (LE-Jetronic)<ref>{{cite web|title=5' E28 520i Control unit L-jetronic|url=http://www.realoem.com/bmw/en/showparts?id=4051-EUR-08-1985-E28-BMW-520i&diagId=13_0241|website=www.realoem.com|accessdate=21 September 2017}}</ref>
* 1984&ndash;1987 [[BMW E30|E30 3 Series]] 320i (LE-Jetronic)
* 1986&ndash;1987 [[BMW E28|E28 5 Series]] 520i (Motronic)<ref>{{cite web|title=5' E28 520i Uncoded DME control unit|url=https://www.realoem.com/bmw/en/showparts?id=4031-EUR-07-1987-E28-BMW-520i&diagId=12_1305|website=www.realoem.com|accessdate=21 September 2017}}</ref>
* 1987&ndash;1992 [[BMW E30|E30 3 Series]] 320i (Motronic)
* 1988&ndash;1990 [[BMW E34|E34 5 Series]] 520i (Motronic)
* 1989&ndash;1992 [[Bertone Freeclimber]] (Freeclimber I)

=== M20B23 ===
In March 1978 (six months after the M20 was launched), a fuel-injected and larger displacement version known as the ''M20B23KE'' (or ''M60/5'') was introduced. This version uses the same head (known as "200") and block as the 2.0&nbsp;litre version but a longer {{Convert|76.8|mm|in|2|abbr=on}} stroke crank. The bore is {{Convert|80|mm|in|2|abbr=on}} and it has a capacity of {{convert|2316|cc|L|1|abbr=on}}. Fuel injection was K-Jetronic, the compression ratio is 9.5:1, the power output is {{convert|105|kW|PS hp|0|abbr=on}}<ref name="1977 IAA"/> and the redline is 6,400&nbsp;rpm.<ref name="WC81"/>

The 1982 version used LE-Jetronic, the 731 cylinder head, a compression ratio of 9.8:1 and the other upgrades as the per the 2.0&nbsp;litre version. This version is called the ''M20B23LE'' and has a power output of {{convert|102|kW|0|abbr=on}}.

In September 1983, the M20B23LE's fuel-injection, exhaust and camshaft were upgraded and power increased to {{convert|110|kW|0|abbr=on}} with a redline of 6,500&nbsp;rpm. The {{convert|102|kW|0|abbr=on}} version continued to be available in certain markets with strict emissions regulations (such as Switzerland) until replaced by the 325i.<ref name="AR84">{{cite book | title = Automobil Revue '84 | editor-last = Büschi | editor-first = Hans-Ulrich | publisher = Hallwag, AG | language = German, French | page = 179 | location = Berne, Switzerland | volume = 79 | date = March 1, 1984 | isbn = 3-444-06070-X }}</ref>

The M20B23 versions were  not sold in North America.

Applications:
* 1977&ndash;1982 [[BMW E21|E21 3 Series]] 323i (K-Jetronic)<ref name="bmwheaven_323i">{{cite web|url=https://www.bmwheaven.com/database/show.php?id=133|title=BMW Heaven Specification Database - Specifications for BMW 323i E21 (1977-1982)|author=Ilir Dibrani|publisher=www.bmwheaven.com}}</ref>
* 1982&ndash;1984 [[BMW E30|E30 3 Series]] 323i (L-Jetronic)
* 1984&ndash;1987 [[BMW E30|E30 3 Series]] 323i (LE-Jetronic)

=== M20B25 ===
In 1985, the M20B25 replaced the M20B23. The M20B25 has a capacity of {{convert|2494|cc|cuin|1|abbr=on}} and initially produced {{cvt|171|PS|kW PS hp|0|order=out}} (without a [[catalytic converter]]).<ref name="bmwheaven_M20">{{cite web|url=https://www.bmwheaven.com/database/engine.php?type=M20|title=BMW Heaven Specification Database - Engine specifications for M20 engines|first=Ilir | last = Dibrani|publisher=www.bmwheaven.com}}</ref> It has an upgraded cylinder head (known as "885"), a bore of {{convert|84|mm|in|2|abbr=on}}, a stroke of {{convert|75|mm|in|2|abbr=on}}, a compression ratio of 9.4:1, a redline of 6,500&nbsp;rpm and uses [[Motronic#1.1|Bosch Motronic 1.1]] engine management.<ref name="e30world">{{cite web|url=https://e30world.com/specifications/BMW-E30-specs-table |title= BMW E30 Specifications |website=www.e30world.com |url-status=dead |archiveurl=https://web.archive.org/web/20130224032538/http://e30world.com/specifications/BMW-E30-specs-table |archivedate=24 February 2013}}</ref><ref name="AR87"/>

In 1987, a catalyzed model with Motronic 1.3 engine management was introduced.<ref>{{cite web|title=3' E30 325i Uncoded DME control unit|url=https://www.realoem.com/bmw/en/showparts?id=1411-EUR-01-1988-E30-BMW-325i&diagId=12_0856|website=www.realoem.com|accessdate=21 September 2017}}</ref><ref name="AR87"/> The compression ratio was reduced to 8.8:1 but thanks to the more sophisticated electronics power remained nearly as before, at {{cvt|170|PS|kW PS hp|0|order=out}}. The uncatalyzed engine was kept in production for Southern Europe and other markets where unleaded petrol was not regularly available.

Applications:
* 1985&ndash;1993 [[BMW E30|E30 3 Series]] 325i
* 1989&ndash;1990 [[BMW E34|E34 5 Series]] 525i
* 1988&ndash;1991 [[BMW Z1|Z1]]

=== M20B27 ===
The M20B27 was designed for efficiency (thus the ''e'' for the Greek letter ''eta'' in ''325e'') and low-rev torque.<ref>{{cite web|url=https://www.e30info.com/pages/diff.htm|title=BMW e30 1983-1991 differences between models|publisher=www.e30info.com}}</ref> This is an unusual design strategy for a BMW straight-six engine, which are usually designed for power at high RPM. Compared with the M20B25, the stroke is increased from {{convert|75|to|81|mm|in|2|abbr=on}}, resulting in a capacity of {{convert|2693|cc|cuin|1|abbr=on}}.<ref name="e30world" /> Since many markets tax cars based on engine displacement, the eta's larger displacement meant that it was not suitable for all markets. It was expressly developed with the American market in mind. As per the M20B25, the bore is {{Convert|84|mm|in|2|abbr=on}}. To reduce friction and improve efficiency, the M20B27 changes include using the '200' version of the head (which has smaller ports), a different camshaft, four camshaft journals and softer valve springs. Due to these changes the rev limit on the M20B27 was reduced to 4,800&nbsp;rpm. The initial version, called the ''M20B27ME'', produces {{convert|123|hp|kW|0|abbr=on|order=flip}} and {{convert|177|lb·ft|N.m|abbr=on|order=flip}} at 3,250&nbsp;rpm for models without a catalytic converter.<ref name="e30world" /> Models with a catalytic converter produce {{convert|121|hp|kW|0|abbr=on|order=flip}} and {{convert|170|lb·ft|N.m|abbr=on|order=flip}}.

In the United States, BMW's [[corporate average fuel economy]] was at risk of not meeting requirements by 1984, primarily due to higher sales of their bigger, more expensive cars in the early 1980s.<ref name=AG941>{{cite magazine | ref = AG94 | magazine = De AutoGids | number = 94 | volume = 4 | page = 130 | title = BMW: Met de ETA op de zuinige tor | trans-title = BMW: With Eta on an economy run | first = Vic | last = Heylen | language = Dutch | date = 1983-04-28 | publisher = Uitgeverij Auto-Magazine | location = Brussels, Belgium }}</ref> The first car to use the M20B27 was the US market 528e in 1982. The compression ratio of the U.S. M20B27ME version was 9.0:1, compared with for cars sold elsewhere 11.0:1.

In 1985, the ''M20B27ME.E'' version was introduced, increasing power output to {{convert|95|kW|0|abbr=on}} despite a lower compression ratio of 10.3:1.<ref>{{cite web|title=M20B27 Engine Specs|url=https://www.e30tech.com/forum/showthread.php?t=13930|website=www.e30tech.com|accessdate=21 September 2017|archive-url=https://web.archive.org/web/20170923095550/http://www.e30tech.com/forum/showthread.php?t=13930|archive-date=23 September 2017|url-status=dead}}</ref>

In late 1987, the fuel injection was upgraded to Motronic 1.3 on the US market plastic bumper 325e and 528e 'Super Eta',<ref>''Automobil Revue '83'', p. 206</ref><ref name="AK86">{{cite book | title = Auto Katalog 1986 | publisher = [[:de:Motor Presse Stuttgart|Vereinigte Motor-Verlage GmbH & Co. KG]] | editor-last = Heitz | editor-first = Rudolf | location = Stuttgart | page = 210 | volume = 29 | language = German | date = 1985-08-01 | id = 81530/85001 }}</ref> the cylinder head changed to the "885" version, the compression ratio was reduced to 8.5:1 and the redline increased to 5,200&nbsp;rpm.<ref>{{cite web|title=325e|url=https://www.e30zone.net/e30zonewiki/index.php/325e|website=www.e30zone.net|accessdate=21 September 2017|archive-date=23 September 2017|archive-url=https://web.archive.org/web/20170923051050/http://www.e30zone.net/e30zonewiki/index.php/325e|url-status=dead}}</ref> Power output increased to {{convert|127|hp|kW|0|abbr=on|order=flip}} at 4,800&nbsp;rpm.

In the early 1990s BMW South Africa used components from the Alpina C3 2.7 to produce an E30 specifically for Stannic Group N production car racing. The first iteration of this engine used in the E30 325iS produced {{convert|145|kW|hp|0|abbr=on}} and the second revision, often referred to as "Evo2" or on the [[VIN]] plate as "HP2" produced {{convert|155|kW|hp|0|abbr=on}}.

Applications:
* 1982&ndash;1987 [[BMW E30|E30 3 Series]] 325e, 325e
* 1982&ndash;1988 [[BMW E28|E28 5 Series]] 525e (called 528e in North America)
* 1989&ndash;1992 [[BMW E30|E30 3 Series]] 325iS (only available in South Africa)
* 1989&ndash;1992 [[Bertone Freeclimber]] (Freeclimber I)

== See also ==
{{Commons category|BMW M20 engine}}
* [[BMW]]
* [[List of BMW engines]]

== References ==
{{reflist|30em}}

{{BMW automotive petrol engines: 1960s to 1980s}}

{{DEFAULTSORT:Bmw M20}}
[[Category:BMW engines|M20]]
[[Category:Straight-six engines]]
[[Category:Gasoline engines by model]]