BMW S85

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BMW S85 engine
BMW S85B50 Engine.JPG
ManufacturerBMW Bayerische Motoren Werke
Production2005–
PredecessorS62
ClassV10
ManualsService Manual

The BMW S85B50 is a DOHC 40-valve V10 automotive piston engine found on the E60 M5 and E63 M6. It was inspired by BMW's formula 1 racing division.

Technology & Performance

The S85B50 is a high-revving engine designed to utilize power from a wide rev band. Having a redline of 8250 rpm, it achieves over 100 bhp (70 kW)/litre and features a very high compression ratio of 12.0:1, beating the previous M3 of 11.5:1

  • 5.0 Litre V10 engine, 507 hp (378 kW) @ 7750rpm/520 N·m (384 lb·ft) torque @ 6100rpm
  • Cast aluminum block with bed plate design split at the crankshaft axis.
  • Cast aluminum heads with four valves per cylinder and CNC machined ports and combustion chambers. Valves are actuated though non-rotating inverted bucked cam followers.
  • Oil cooled forged aluminum pistons from Mahle Motorsport
  • Forged steel crankshaft with counterweights
  • Double VANOS system which varies both intake and exhaust cam phasing
  • 10 individual electronically controlled throttles
  • Knock sensors have been eliminated by utilizing the "ionic current" measuring system. Using the ionic current system, engine misfires as well as knock can be measured simultaneously. Combustion quality raises or lowers cylinder pressure. The ionic current is measured by passing a low voltage across the spark plugs immediately following the ignition spark.
  • Quasi-dry sump lubricating system
  • The Digital Motor Electronic (DME) of the S85B50 is encrypted heavily to prevent modifications/hacking to the software.
  • The firing order for the S85 engine is 1-6-5-10-2-7-3-8-4-9. [1]

Awards

In 2005, the first year that it was nominated, the S85B50 won four different International Engine of the Year awards in the following 4 categories:

  1. International Engine of the Year, BMW 5.0 Litre V10 (M5,M6)
  2. Best Performance Engine
  3. Best New Engine
  4. Best Above 4.0 Litre

In 2006 the S85B50 again won several International Engine of the Year awards, winning in the following 3 categories:

  1. International Engine of the Year, BMW 5.0 Litre V10 (M5,M6)
  2. Best Performance Engine
  3. Best Above 4.0 Litre

In 2007 the S85B50 again won several International Engine of the Year awards, winning in the following 2 categories:

  1. Best Performance Engine
  2. Best Above 4.0 Litre

In 2008 the S85B50 again won an International Engine of the Year award, winning in the following category:

  1. Best Above 4.0 Litre

See also