Related: Automotive Powertrain
Look under the hood of BMW's M5 sedan or M6 coupe and you'll find a decade of cylinders, just like the company's current F1 race engine. Here are the highlights:
- A 5.0-liter 90º V10 producing 507 hp @ 7,750 rpm, 383 lb-ft @ 6,100 rpm, and with 80% of the maximum torque available in a 5,500 rpm band.
- Bore and stroke are 92.0 mm x 75.2 mm, making this a very oversquare engine.
- The crankcase is low-pressure die-cast using an over-eutectic aluminum-silicon alloy with a minimum 17% silicon. The silicon is exposed by machining the cylinders, and the iron-coated pistons (481.7 grams, including rings) run on the uncoated bores.
- Like BMW's F1 engine, the road V10 uses a bedplate structure crankcase. Made from aluminum with a gray cast-iron inset that reduces the thermal expansion of the aluminum housing, it keeps a check on main bearing tolerances and noise.
- The high-strength forged steel crankshaft runs in six main bearings and weighs 48.1 lb.
- Valves are operated by 1.1-in. ball-shaped cup tappets weighing 31 grams. The valves measure 1.38-in. for intake, and 1.20-in. for exhaust. BMW's
- Double VANOS variable valve timing is fitted.
- Four pumps make sure the engine is never starved of oil. Starting at 0.6g, one of two electrically driven pumps pulls oil out of the cylinder head and pumps it back to the sump. The M6 can generate 1.0g in cornering, 1.3g under braking.
- The spark plug electrode is electrically insulated from the cylinder head and connected to a control unit that measures the ionic current flow between the electrodes. This is used to determine when to adjust ignition timing to control knock.–CAS