BMW S85

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BMW S85 engine
BMW S85B50 Engine.JPG
S85B50 in a E60 M5
Overview
ManufacturerGermany BMW
Production2005–2010
Layout
Configuration90° V10
Displacement5.0 L (305 cu in)
Block materialAluminium
Head materialAluminium
ValvetrainDOHC w/ VVT
Combustion
Fuel typePetrol
Output
Power output373 kW (500 hp)
Torque output520 N⋅m (384 lb⋅ft)
Chronology
PredecessorNone
SuccessorBMW S65

The BMW S85 is a naturally aspirated V10 petrol engine which replaced the BMW S62 V8 engine in the M5 model and was produced from 2005–2010. It was both BMW's first and only production V10 engine, and the first petrol V10 engine to be available in a production sedan (saloon).

Introduced in the E60 M5, the S85 was inspired by BMW's previous Formula One involvement.[1] Unlike most other BMW M engines, the S85 is not related to a regular production BMW engine.[2]

The BMW S65 V8 engine (used in the E92 M3) is based on the S85.

Nomenclature[edit]

As the S85 was BMW's first V10 engine, it was given a new series in the BMW's engine codes. The "60s" were used for V8 engines and the "70s" were used for V12 engines, therefore the V10 was allocated in the "80s" (despite having fewer cylinders than the V12 engines in the "70s".)

The engine code for the related BMW S65 V8 engine reflects its link to the S85. The S65 code was selected to signify that the V8 is largely derived from the S85 minus two cylinders, and not related to BMW's other V8s.[3]

Design[edit]

Compilation of the four side views of the BMW V10 engine as it is installed in the BMW M5 and M6
Version Year Displacement Power Torque
S85B50 2005–2010 4,999 cc (305.1 cu in) 373 kW (500 hp)
at 7,500 rpm
520 N⋅m (384 lb⋅ft)
at 6,100 rpm

The S85 has dual overhead camshafts with four valves per cylinder and double-VANOS (variable valve timing).[4] The engine block and cylinder head are constructed from aluminum alloy.[5]

Peak power is 373 kW (500 bhp) at 7,750 rpm and peak torque is 520 N⋅m (384 lb⋅ft) at 6,100 rpm.[6] The redline is 8,250 rpm,[2] and the specific output of 74.6 kW (100.0 bhp) per litre is amongst the highest of naturally aspirated production car engines.

Features include:

  • Displacement of 4,999 cc (305.1 cu in)[6]
  • Compression ratio of 12.0:1[7]
  • Bore of 92 mm (3.62 in) and stroke of 75.2 mm (2.96 in)[6]
  • 10 electronically actuated individual throttle bodies[8]
  • Cast aluminum block with bed plate design[9] split at the crankshaft axis
  • Valves actuated through non-rotating inverted bucket cam followers
  • Oil-cooled, cast aluminium pistons
  • Forged steel crankshaft with counterweights, shared crankpins producing an uneven firing interval of 90 or 54 degrees
  • Siemens MS S65 engine control unit
  • Application of an "ionic current measuring system" for knock sensing.[10] The ionic current system uses a low voltage applied across the spark plugs immediately following the ignition spark, and can detect misfires as well as knock.
  • Quasi-dry sump lubricating system where the engine has 2 oil sumps that hold oil, and oil pickup is enhanced by secondary electrical scavenge pumps that feed oil from the smaller sump to the main sump[11]
  • Uneven Firing order of 1-6-5-10-2-7-3-8-4-9
  • Mass of 240 kg (529 lb)[12]

Awards[edit]

The S85 has won the following awards at the International Engine of the Year:[13]

  • 2005 International Engine of the Year, Best Performance Engine, Best Above 4.0 Litre, Best New Engine
  • 2006 International Engine of the Year, Best Performance Engine, Best Above 4.0 Litre
  • 2007 Best Performance Engine, Best Above 4.0 Litre
  • 2008 Best Above 4.0 Litre

Applications[edit]

  • 2005–2010 E60/E61 M5
  • 2005–2010 E63/E64 M6
  • 2009–2010 Wiesmann GT MF5 (and also 2011 Wiesmann Roadster MF5 V10 daHLer Schwaben Folia Black Bat, V10 engine was upgraded to 600 hp)
  • 2005–2007 Fisker Latigo CS V10 (One prototype and one production car, upgraded from 507 to 650 hp)
  • 2009–2013 Vermot Veritas RS III (30 cars were built, and used a 600-hp version of the S85 engine)

References[edit]

  1. ^ "BMW M5 - 2004 Geneva Auto Show". Insideline.com. 15 May 2007. Archived from the original on 12 June 2012.
  2. ^ a b "2006 BMW M5 - First Drive Review". www.caranddriver.com. December 2004. Archived from the original on 6 September 2011. Retrieved 23 February 2012.
  3. ^ "FAQ - E90 + E92 + E93 M3". www.bmwmregistry.com. Archived from the original on 22 October 2016. Retrieved 21 July 2017.
  4. ^ "2006 BMW M5 review". www.roadandtrack.com. 6 November 2012. Archived from the original on 18 August 2017. Retrieved 25 July 2017.
  5. ^ "BMW S85 engine reliability, problems and repair". mywikimotors.com. Archived from the original on 2 August 2017. Retrieved 25 July 2017.
  6. ^ a b c "BMW M5 Sedan Engine and Chassis Technical Data". BMW AG. Archived from the original on 12 August 2008. Retrieved 4 July 2017.
  7. ^ "BMW S85 V10 and S65 V8 Engines". www.unixnerd.demon.co.uk. Archived from the original on 23 January 2016. Retrieved 28 July 2017.
  8. ^ "BMW Retires the M6 & The Mighty S85 V10". www.bimmerfile.com. 8 September 2010. Archived from the original on 13 October 2017. Retrieved 4 July 2017.
  9. ^ "BMW's new V10 engine in detail". www.newatlas.com. 21 January 2004. Archived from the original on 14 April 2017. Retrieved 25 July 2017.
  10. ^ "BMW S85 engine". www.australiancar.reviews. Archived from the original on 20 July 2017. Retrieved 25 July 2017.
  11. ^ "Archived copy". Archived from the original on 2019-01-08. Retrieved 2017-07-27.{{cite web}}: CS1 maint: archived copy as title (link)
  12. ^ "Review: BMW E60 LCI M5 (2007-10)". www.ukcar.reviews. Archived from the original on 30 March 2018. Retrieved 25 July 2017.
  13. ^ "International Engine of the Year - Archive". www.ukimediaevents.com. Archived from the original on 3 December 2017. Retrieved 28 July 2017.