BMW S85 Engine (S85B50)
|Also called||BMW S85|
|Cylinder block alloy||Aluminum|
4 valves per cylinder
|Piston stroke, mm (inch)||75.2 (2.96)
|Cylinder bore, mm (inch)||92 (3.62)|
|Displacement||4999 cc (305.1 cu in)
|Power output||373 kW (507 HP) at 7,750 rpm
|Torque output||520 Nm (384 lb·ft) at 6,100 rpm
|HP per liter||101.4
|Weight, kg (lbs)||240 (530)|
|Fuel consumption, L/100 km (mpg)
|for E60 M5
|Oil consumption , L/1000 km
(qt. per miles)
|up to 1.0
(1 qt. per 750 miles)
|Recommended engine oil||10W-60
|Engine oil capacity, L (qt.)||9.3 (9.8)|
|Oil change interval, km (miles)||5,000-10,000
|Normal engine operating temperature, °C (F)||–|
|Engine lifespan, km (miles)
-No life span loss
|The engine is installed in||BMW M5 E60
BMW M6 E63
The next BMW M5 E60 produced in 2005 and became heavier. So the old S62 was not enough for competition with fast Audi RS6 and Mercedes-Benz E55/E63 AMG. S85B50 made from the scratch. It didn’t base on civil motors. In the design used ideas from P84/5 race engine installed in the F1 Williams FW27.
The BMW S85 engine got light aluminum 90° the cylinder block with 10 cylinders. These cylinders are arranged with an offset of 17 mm. This engine does not use liners. There are piston cooling-oil nozzles and aluminum oil pan. In design the block is the same as BMW N52. For S85B50 use reinforced forged crankshaft, lightweight connecting rods (their length is 140.7 mm), pistons of aluminum alloy (compression ratio is 12) with compression height of 27.4 mm.
The cylinder head of S85 aluminum with 4 valves per cylinder and hydraulic lifters. This engine use variable valve timing system Double-VANOS on intake and exhaust camshafts. The system is similar to the S62 Double-VANOS. Adjustment of camshafts: intake 60°, exhaust 37°. Features of the camshafts on the E60 M5: duration 268/260 deg, lift 11.7/11.5 mm. The diameter of the inlet valves 35 mm exhaust – 30.5 mm, stem diameter 5 mm.
Intake individual throttle bodies installed in 2 rows of 5 pieces, and optimized the intake manifold. Performance fuel injectors – 192 cc/min. Exhaust installed equal length exhaust header 5-1 on each catalytic converter. BMW S85 firing order: 1-6-5-10-2-7-3-8-4-9.
The engine control unit of the S85 – DME MS S65. All this allows to get 507 horsepower at 7,750 rpm, redline at this engine is 8,250 rpm. The BMW S85 motor installed on E60/E61 M5 and on E63/E64 M6. For the BMW M3 E92/E90, the S85 simplified and named S65B40. S85B50 stopped to produce in 2010, together with E60 M5. The following BMW F10 M5 used new turbocharged V8 S63.
BMW S85B50 engine problems and malfunctions
The M5 E60 motor has a problem with premature wear of connecting rod bearings. You need to change their every 50,000 miles of mileage (80,000 km) not to get more serious problems. It is necessary periodically to repair VANOS system. In general the motor is normal if you regularly service it and not overheat.
S85 Stroker. Cams
The S85 engine from the factory has high power, but some stock still left. The easiest way to buy cat-back exhaust system (like Supersprint), intake system Gruppe M, pulley and ECU software.
It give about 560 horsepower. If you buy the 294/282 camshafts, Dinan ITB and ECU tuning, then your E60 M5 will show 580+ horsepower. This kit allow you to get 1/4 mile in 12 sec.
Also you can buy E60 M5 stroker kit. By installing the crankshaft with a piston stroke of 82 mm, pistons of 94 mm, you get 5.8 liter capacity. If you keep on stock pistons, capacity will be only 5.6 liter. Buying everything that is written above, you get 620-630 horsepower.
A cheaper alternative to what is written above, may be E60 M5 supercharger kit. The most popular is ESS VT2 based on Vortech V3Si supercharger. This supercharger kit installs on stock internals and has the maximum boost 7 psi (0.5 bar). It will allow to get 650 horsepower easily. Don’t forget about ESS connecting rod bearings, it keep reliability.