View source for Engineering:BMW M51

{{Infobox automobile engine
| name          = BMW M51
| image         = M51_Motor.JPG
| manufacturer  = BMW
| aka           = 
| production    = 1991-2000
| predecessor   = [[Engineering:BMW M21|BMW M21]]
| successor     = [[Engineering:BMW M57|BMW M57]]
| configuration = Inline-6
| displacement  = {{convert|2497|cc|L cuin|1|order=flip|abbr=on}}
| bore          = {{convert|80|mm|2|abbr=on}}
| stroke        = {{convert|82.8|mm|2|abbr=on}}
| block         = [[Chemistry:Cast iron|Cast iron]]
| head          = 
| valvetrain    = SOHC 2 valves x cyl.
| compression   = 22.0:1
| supercharger  = 
| turbocharger  = Single turbo, tds-engines also have an [[Physics:Intercooler|intercooler]]
| fuelsystem    = [[Engineering:Indirect injection#Swirl chamber|Swirl-chamber-injection]]
| management    = Bosch DDE 2.1
| fueltype      = [[Chemistry:Diesel fuel|Diesel fuel]] (DIN 51601)
| oilsystem     = 
| coolingsystem = [[Engineering:Radiator (engine cooling)|Water-cooled]]
| power         = {{convert|85-105|kW|0|abbr=on}}
| specpower     = 
| torque        = {{convert|222-280|Nm|lbft|0|abbr=on}}
| length        = 
| width         = 
| height        = 
| diameter      = 
| weight        = {{convert|132|kg|lb|0|abbr=on}}
}}

The '''BMW M51''' is an inline-6 cylinder Diesel engine produced by the Upper Austrian BMW plant in Steyr from July 1991 through February 2000. Its predecessor is the [[Engineering:BMW M21|BMW M21]], the successor is the [[Engineering:BMW M57|BMW M57]].

== Description ==

The M51 is a water-cooled and turbocharged inline six-cylinder diesel engine with a Bosch VP37-[[Engineering:Indirect injection#Swirl chamber|swirl-chamber-injection]].<ref name="carspecs" /><ref name="Bimmertoday" /><ref>{{cite web |title=BMW M41 and M51 Diesel Engines |url=http://www.unixnerd.demon.co.uk/m51.html |website=www.unixnerd.demon.co.uk |archive-url=https://web.archive.org/web/20161010201254/http://www.unixnerd.demon.co.uk/m51.html |archive-date=10 October 2016 |url-status=dead}}</ref> The displacement is {{convert|2497|cc|L cuin|1|order=flip|abbr=on}} and the [[Engineering:Compression ratio|compression ratio]] is 22.0:1.

Some engine variants have an intercooler in addition to the turbocharger, they can be identified by the ''tds''.<ref name="Bimmertoday" /> The M51 is an engine made of cast iron, it has one chain driven overhead camshaft<ref name="Etzold" /> and two valves per cylinder.<ref name="Bimmertoday" /><ref name="Etzold" /> Compared to the M21 the M51 now has tappets and a hydraulic valve lash adjustment.<ref name="Bimmertoday" /> The fuel injection in the first engines and all E36 models is controlled by the ECU Bosch DDE 2.1, which was replaced after the first technical revision by the DDE 2.2<ref name="Etzold" /> This results in greater torque at lower revs.<ref name="Etzold" /> For lubrication SAE 5W-40 oil is used.<ref name="öl" />

{| class="wikitable sortable"
! Version !! Power !! Torque !! Years
|-
| M51D25 UL || {{cvt|115|hp-metric|kW|0|disp=flip}} <br/> at 4800&nbsp;rpm || {{convert|222|Nm|lbft|0|abbr=on}} <br/> at 1900&nbsp;rpm ||1991–1997
|-
| M51D25 OL || {{cvt|105|kW|hp-metric|0}} <br/> at 4800&nbsp;rpm || {{convert|260|Nm|lbft|0|abbr=on}} <br/> at 2200&nbsp;rpm || 1991–1996
|-
| Opel X25DT{{efn|For [[Engineering:Opel Omega#Omega B1 (1994–1999)|Opel Omega B]] only}}|| {{cvt|130|hp-metric|kW|0|disp=flip}} <br/> at 4800&nbsp;rpm<ref>{{cite web |title=Vauxhall V94 - Omega B confidential launch guides |url=http://vauxpedianet.uk2sitebuilder.com/vauxhall-v94---omega-b-confidential-launch-guides |website=vauxpedianet.uk2sitebuilder.com |access-date=2 October 2021 |archive-date=1 October 2021 |archive-url=https://web.archive.org/web/20211001002507/http://vauxpedianet.uk2sitebuilder.com/vauxhall-v94---omega-b-confidential-launch-guides |url-status=dead }}</ref><ref name="tuning" /><ref>{{cite web |title=Detailed specs review of 1995 Opel Omega 2.5 TD model for Europe |url=https://www.automobile-catalog.com/car/1995/2490050/opel_omega_2_5_td.html |website=www.automobile-catalog.com |access-date=14 August 2021}}</ref><ref>{{cite web |title=Opel Omega 2.5 TD CD Manual 4 doors specs |url=https://www.cars-data.com/en/opel-omega-2.5-td-cd-specs/32148 |website=www.Cars-Data.com |access-date=14 August 2021 |language=en}}</ref> || {{convert|250|Nm|lbft|0|abbr=on}} <br/> at 1400&nbsp;rpm || 1994–2001
|-
| M51D25TÜ UL || {{cvt|115|hp-metric|kW|0|disp=flip}} <br/> at 4800&nbsp;rpm<ref>{{cite web |title=Die BMW Turbodiesel |url=https://bmw-grouparchiv.de/research/detail/index.xhtml?id=3133066 |website=bmw-grouparchiv.de |access-date=30 September 2021}}</ref><ref>{{cite web |title=Betriebsanleitung zum Fahrzeug. [BMW 5er Limousine/touring (E39)] |url=https://bmw-grouparchiv.de/research/detail/index.xhtml?id=8171281 |website=bmw-grouparchiv.de |access-date=30 September 2021}}</ref> || {{convert|230|Nm|lbft|0|abbr=on}} <br/> at 1900&nbsp;rpm || 1996–1998
|-
| M51D25TÜ OL || {{cvt|105|kW|hp-metric|0}} <br/> at 4800&nbsp;rpm<ref name="Etzold" /> ||rowspan="2"| {{convert|280|Nm|lbft|0|abbr=on}} <br/> at 2200&nbsp;rpm || 1996–1998
|-
| M51D25TÜ OL || {{cvt|105|kW|hp-metric|0}} <br/> at 4600&nbsp;rpm<ref name="Etzold" /> || 1998–2000
|-
| M51D25M1{{efn|For [[Engineering:Range Rover (P38A)|Range Rover P38]] DSE 2.5 LP2 only.}} || {{cvt|100|kW|hp-metric|0}} <br/> at 4400&nbsp;rpm<ref name="rangerover" /> || {{convert|270|Nm|lbft|0|abbr=on}} <br/> at 2300 rpm ||1995-2001
|}

{{notelist}}

Applications:
* 1991 - 1996 E36 325td (M51D25 UL)
* 1996 - 1998 E36 325td (M51D25TÜ UL)
* 1993 - 1996 E36 325tds (M51D25 OL)
* 1996 - 1998 E36 325tds (M51D25TÜ OL)
* 1992 - 1996 E34 525td (M51D25 UL)
* 1991 - 1996 E34 525tds (M51D25 OL)
* 1996 - 2000 E39 525tds (M51D25TÜ OL)
* 1996 - 2000 E39 525td (M51D25TÜ UL)
* 1996 - 2000 E38 725tds (M51D25TÜ OL)
* 1995 - 2001 [[Company:Land Rover|Land Rover]] [[Engineering:Range Rover|Range Rover 2.5 D/DSE]]
* 1995 - 2001 [[Engineering:Opel Omega|Opel Omega]]
* 1992 [[Engineering:UMM Alter II|UMM Alter II]] (single example; engine, gearbox, and electronics were fitted by BMW in Munich)

==See also==
* [[Engineering:List of BMW engines|List of BMW engines]]

== References ==

<references>
<ref name="Bimmertoday">[http://www.bimmertoday.de/2012/01/21/die-bmw-sportdiesel-von-524td-e28-uber-530d-e39-bis-m550d-f10/ Die BMW-Sportdiesel: Von 524td E28 über 530d E39 bis BMW M550d F10] (german)</ref>
<ref name="tuning">[http://www.dieseltuning.de/tuning-fuer-alle-motoren/opel/omega/opel-omega-b-2-5-td-96-kw-130-ps-motor-25dt-x25dt-x25td-eco-optimierung-leistungssteigerung/a-1928471149/ Opel Omega B 2.5 TD 96 kW 130 PS - Motor: 25DT, X25DT, X25TD - Eco Optimierung / Leistungssteigerung] (german)</ref>
<ref name="Etzold">Etzold: [http://www.delius-klasing.de/sixcms/media.php/9/swg_bmw_5er_leseprobe.pdf So wird's gemacht: pflegen – warten – reparieren. Band 102, BMW 5er E39] {{Webarchive|url=https://web.archive.org/web/20170517005453/http://www.delius-klasing.de/sixcms/media.php/9/swg_bmw_5er_leseprobe.pdf |date=2017-05-17 }} Delius Klasing Verlag. Pages 12 and 13 (german)</ref>
<ref name="carspecs">[http://www.ultimatespecs.com/de/car-specs/BMW/195/BMW-E38-7-Series-725-tds.html BMW E38 7 Series 725 tds Technical data]</ref>
<ref name="öl">[http://www.oil-club.ru/wp-content/uploads/2013/01/BMW.pdf Übersicht der Motorölqualitäten]. Page 7 (german)</ref> 
<ref name="rangerover">[http://www.automobile-catalog.com/car/1997/1398605/range_rover_2_5_dse.html Automobile Catalogue: 1997 Range Rover 2.5 DSE (model for Europe ) specifications & performance data review].</ref>
</references>

{{DEFAULTSORT:Bmw M51}}
[[Category:Diesel engines by model]]

{{Sourceattribution|BMW M51}}