The BMW S85 is Beautifully Engineered
Very possibly the highest output N/A road-going engine BMW will ever make.
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 which is an incredible feat for a naturally aspirated production engine, as other manufacturers have used supercharging or turbocharging to reach a similar output level. The S85 features a very high compression ratio of 12.0:1, exceeding the previous S54’s ratio of 11.5:1
- 5.0 Litre V10 engine, 90 degree bank angle, 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 through non-rotating inverted bucked cam followers.
- Oil-cooled, forged aluminum pistons from Mahle Motorsport
- Forged steel crankshaft with counterweights, shared crankpins producing an uneven firing interval of 90 or 54 degrees.
- Double VANOS system which varies both intake and exhaust cam phasing
- 10 individual electronically controlled throttle butterflies
- 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. 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 firing order for the S85 engine is 1-6-5-10-2-7-3-8-4-9.
