View source for BMW M88

{{Use dmy dates|date=May 2021}}
{{Infobox automobile engine
|image=Bmw m88.jpg
|name=BMW M88 engine
|aka = {{ubl
  | BMW M30B35LE
  | BMW M90
  }}
|manufacturer=[[BMW]]
|production=1978&ndash;1989
|predecessor=None
|successor=[[BMW S38]]
|configuration= [[Straight-6]]
|bore={{cvt|93.4|mm|in|1}}
|stroke={{cvt|84|mm|in|1}}
|displacement={{convert|3453|cc|L|1|abbr=on|order=flip}}
|valvetrain= [[DOHC]] (M88) <br/> [[SOHC]] (M30B35LE/M90)
|fueltype=[[Petrol]]
|head=[[Aluminium]]
|block=[[Cast iron]]
}}

The [[BMW]] '''M88''' is a [[Straight-six engine|straight-6]] [[DOHC]] [[petrol engine]] which was produced from 1978 to 1989. It is based on the DOHC version of the BMW M49 engine, which was used in the [[BMW E9|BMW 3.0CSi]] racing cars.<ref name="gtspirit.com">{{cite web |title=The Story of 40 Years BMW M ‒ The BMW M1 |url=http://gtspirit.com/2012/06/01/the-story-of-40-years-bmw-m-%e2%80%92-the-bmw-m1/ |website=gtspirit.com |access-date=13 December 2018}}</ref><ref name="mydriftfun.com">{{cite web |title=Top 5 Great BMW Engines |url=https://mydriftfun.com/top-5-great-bmw-engines/ |website=mydriftfun.com |access-date=13 December 2018 |date=11 May 2017 |archive-url=https://web.archive.org/web/20181215222126/https://mydriftfun.com/top-5-great-bmw-engines/ |archive-date=15 December 2018}}</ref><ref>{{cite web|url=https://infernalco.co/2018/03/20/m-divisions-greatest-competition-engines/ |title=M Division's Greatest Competition Engines – Infernal Combustion |publisher=Infernalco.co |date=20 March 2018 |accessdate=31 May 2021}}</ref>

The M88 was produced alongside the [[BMW M30]] engine, as the higher performance engine. In North America up until 1989, the [[BMW S38]] engine was used instead of the M88. In 1989, an updated version of the S38 became the worldwide replacement for the M88. The M30B35LE is a [[SOHC]] engine which is based on the M88/1; this is sometimes referred to as the M90.

==Design==
BMW engineers used a [[Overhead camshaft#Dual overhead camshaft|DOHC]] valvetrain on a production engine for the first time on the M88, with the [[camshaft]]s driven by a single-row [[timing chain]].<ref>{{cite web|author=Horatiu Boeriu |url=http://www.bmwblog.com/2012/05/24/chris-harris-drives-the-e28-bmw-m5/ |title=Chris Harris Drives the E28 BMW M5 |publisher=Bmwblog.com |date=24 May 2012 |accessdate=31 May 2021}}</ref> [[Kugelfischer]] fuel injection<ref name=projectM1 /> was used with individual [[throttle]] valves<ref>{{cite web|url=http://www.bimmerforums.com/engine_faq.php |title=Engine FAQ |publisher=Bimmerforums.com |date=23 August 2009 |accessdate=31 May 2021}}</ref> and the distinctive six [[Throttle body|individual throttle bodies]].

The construction is an aluminium [[cylinder head]] and a cast iron [[Cylinder block|block]].<ref>{{cite web |title=1984 BMW 745i E23 5-Speed manual M88 engined SA model road test |url=https://drive-my.com/en/blogs/entry/1984-bmw-745i-e23-5-speed-manual-m88-engined-sa-model-road-test.html |website=drive-my.com |date=16 March 2016 |access-date=2 December 2018 |language=en-gb}}</ref><ref>{{cite web |title=BMW M88 and S38 M-Tech 24 Valve Six Cylinder Engines |url=http://www.unixnerd.demon.co.uk/s38.html |website=unixnerd.demon.co.uk |access-date=2 December 2018 }}{{Dead link|date=July 2025 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> The [[bore (engine)|bore]] is {{convert|93.4|mm|in|2|abbr=on}} and the [[stroke (engine)|stroke]] is {{convert|84.0|mm|in|2|abbr=on}}, resulting in a [[Engine displacement|displacement]] of {{convert|3453|cc|cuin|1|abbr=on}}.

==Versions==
{|class="wikitable sortable" style="text-align: center;"
|-
! Engine code !! Power !! Torque !! Years !! Note
|-
|M88
|{{cvt|277|PS|kW PS hp|0|order=out}} <br/> at 6,500&nbsp;rpm || {{convert|330|Nm|lbft|0|abbr=on}} <br/> at 5,000&nbsp;rpm || 1978-1981 || BMW M1
|-
|M88/1
|{{cvt|470|PS|kW PS hp|0|order=out}} <br/> at 9,000&nbsp;rpm || {{convert|390|Nm|lbft|0|abbr=on}} <br/> at 7,000&nbsp;rpm || 1979-1980 || Gr.4 Procar
|-
|M88/2<ref>{{Cite web|url=https://www.automobilsport-magazin.de/en/back-issues/issue/articles/issue-07.html|title=Issue #07}}</ref><ref>{{Cite web|url=https://www.bmw-motorsport.com/en/topics/magazine-article-pool/bmw-turbo-engine-evolution.html|title = From M121 to P48: An overview of the evolution of BMW Turbo engines in motor racing}}</ref>
|up to {{cvt|850-1000|PS|kW PS hp|0|order=out}} <br/> at 9,000&nbsp;rpm || {{convert|847-1017|Nm|lbft|0|abbr=on}} at 7,000&nbsp;rpm<ref>{{Cite web|url=https://spicerparts.com/calculators/horsepower-torque-calculator|title = Spicer Horsepower and Torque Calculator}}</ref> || 1979-1981 || Gr. 5 turbo
|-
|M88/3
|{{cvt|286|PS|kW PS hp|0|order=out}} <br/> at 6,500&nbsp;rpm || {{convert|340|Nm|lbft|0|abbr=on}} <br/> at 4,500&nbsp;rpm || 1983–1989 || M635 CSi, M5, 745i (South Africa only)
|-
|M30B35LE/M90
|{{cvt|218|PS|kW PS hp|0|order=out}} <br/> at 5,200&nbsp;rpm || {{convert|304|Nm|lbft|0|abbr=on}} <br/> at 4,000&nbsp;rpm ||1978–1982 || SOHC
|}

===M88===
[[File:BMW M1 Ausstellungsmotor.jpg|thumb|M88/1 with some parts replaced with Plexiglas for display purposes]]
The M88 was the original iteration of the engine and was fitted to the [[BMW M1]]. It produces {{cvt|277|PS|kW hp}} at 6,500&nbsp;rpm and {{cvt|330|Nm|lbft}} at 5,500&nbsp;rpm. A [[dry sump]] is used.<ref>{{cite web|title=The BMW Six Cylinder Guide|url=http://www.autospeed.com/cms/article.html?&title=The-BMW-Six-Cylinder-Guide&A=2948|website=autospeed.com}}</ref>

Applications:
* 1978-1981 [[BMW M1|M1]]

===M88/1===
For the BMW M1 [[BMW M1 Procar Championship|Procar]] single-make series, the M88 engine was bored out marginally to reach {{convert|3498|cc|L|1|abbr=on}}. This racing version, called the '''M88/1''', met the [[Group 4 (racing)|Group 4]] regulations. This race engine produced {{cvt|350|kW|PS hp}} in Procar specifications. This version had forged pistons, sharper camshafts, bigger valves, as well as oil cooling for the transmission and rear differential.

Applications:
* 1979-1980 [[BMW M1 Procar Championship|Procar]] BMW M1

===M88/2===
For Group 5 racing, the M88 engine was turbocharged and became known as the M88/2. It was downsleeved and had a shorter stroke to displace {{convert|3191|cc|L|1|abbr=on}}, which with the 1.4 turbo factor placed it in the 4.5-liter class. This race engine produced up to {{cvt|670|kW|PS hp}}.<ref name=carlust>{{cite web |url=http://www.carlustblog.com/2012/05/bmw-m1.html |title=Car Lust: BMW M1 |access-date=15 August 2012 |url-status=dead |archive-url=https://web.archive.org/web/20120713005747/http://www.carlustblog.com/2012/05/bmw-m1.html |archive-date=13 July 2012 }}</ref>

Applications:
* [[Group 5 (racing)|Group 5]] racing cars ([[BMW M1 (Group 5)|BMW M1 Group 5 page]])

===M88/3===
[[File:BMW_M88_3_Auspuffseite.JPG|thumb|M88/3 iteration used in the [[BMW M6#E24 M635CSi/M6 (1983–1989)|E24 M635CSi]] and [[BMW M5#E28|E28 M5]].]]
The M88/1 engine was modified for use in the [[BMW M6#E24 M635CSi/M6 (1983–1989)|E24 M635CSi]] and [[BMW M5#E28|E28 M5]] and was known as the M88/3.<ref>{{cite web |url=http://www.usautoparts.net/bmw/models/m_series_history.htm |title=BMW World - BMW M Parts Series |access-date=15 August 2012 |url-status=dead |archive-url=https://web.archive.org/web/20131023232703/http://www.usautoparts.net/bmw/models/m_series_history.htm |archive-date=23 October 2013 }}</ref> The [[Kugelfischer]] [[fuel injection]] was replaced with [[Robert Bosch GmbH|Bosch]] [[Motronic]] producing {{cvt|210|kW|PS hp}} at 6,500&nbsp;rpm and {{cvt|340|Nm|lbft}} at 4,500&nbsp;rpm.<ref>{{cite web|url=http://www.bmwmregistry.com/model_faq.php?id=5 |title=FAQ E24 M635CSi + M6 |publisher=BMW M Registry |accessdate=31 May 2021}}</ref> It has a [[compression ratio]] of 10.5:1.

The M88/3 was also fitted to the South African BMW 745i, due to packaging problems with the turbocharged [[BMW M102|M102]] engine which was used in other markets.<ref>{{cite web|url=http://www.bmwmregistry.com/model_faq.php?id=4 |title=FAQ E23 745i SA (M88) |publisher=BMW M Registry |accessdate=31 May 2021}}</ref>

Applications:
* 1983-1989 [[BMW 6 Series (E24)|E24]] M635CSi
* 1984-1987 [[BMW 5 Series (E28)|E28]] M5
* 1984-1987 [[BMW 7 Series (E23)|E23]] 745i (South Africa only)

=={{anchor|M90|M30B35|SOHC}} M30B35LE==
The '''M30B35LE''' is a lower performance, two-valve, [[SOHC]] version of the M88/1 engine, also known as the '''M90'''. It utilizes the same block as the M88 and maintains the same bore and stroke, but borrows its head from the [[BMW M30]] engine family. Depending on year, this engine uses either Bosch [[Motronic]] or Bosch [[L-Jetronic]] as its engine management system.<ref name=projectM1>{{cite web|url=http://www.projectm1.com/index_files/Technology.htm |title=M1 Technology |publisher=Projectm1.com |accessdate=31 May 2021}}</ref>
Typically identified by a white L painted on the block behind the oil filter housing and coolant water passages on the side of the block.

As sold in Europe and most other markets (except North America), this engine used a compression ratio of 9.3:1, did not have a [[catalytic converter]], and produced {{cvt|160|kW|PS hp}}.

Applications:
* 1979-1981 [[BMW E12|E12]] [[BMW 5-Series|M535i]]
* 1978-1982 [[BMW E24|E24]] [[BMW 6-Series|635CSi]]
* 1978-1982 [[BMW E23|E23]] [[BMW 7-Series|735i]]

==See also==
*[[BMW S14]] - Four-cylinder engine based on the M88

==References==
{{reflist}}

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

{{DEFAULTSORT:Bmw M88}}
[[Category:BMW engines|M88]]
[[Category:World Sportscar Championship engines]]
[[Category:Straight-six engines]]
[[Category:Gasoline engines by model]]