BMW N73

The BMW N73 is a naturally aspirated V12 petrol engine which replaced the BMW M73 and was produced from 2003–2016. It was used in the BMW 7 Series (E65) and Rolls-Royce Phantom VII.

BMW N73 engine
Overview
Production	2003–2016
Layout
Configuration	60° V12
Displacement	6.0 L (5,972 cc) 6.7 L (6,749 cc)
Cylinder bore	89 mm (3.50 in) 92 mm (3.62 in)
Piston stroke	80 mm (3.15 in) 84.6 mm (3.33 in)
Valvetrain	DOHC w/ VVT & VVL
Combustion
Fuel type	Petrol
Chronology
Predecessor	BMW M73
Successor	BMW N74

The N73 was the world's first production V12 engine to use gasoline direct injection.^[1]

Compared with its M73 predecessor, the N73 has dual overhead camshafts, double-VANOS (variable valve timing) and valvetronic (variable valve lift).^[2][3]

Design

The variable valve timing (VANOS) is a continuously variable design and is present on both the intake and exhaust camshafts. The VANOS units were designed as integral components of the chain drive, and the adjustment ranges are 63 degrees for the intake camshaft and 60 degrees for the exhaust camshaft.^[4] The redline for the N73 is 6,500 rpm.

The N73 engine also has variable valve lift (valvetronic), which varied intake valve opening lift from 0.30–9.85 mm (0.01–0.39 in), according to engine speed and load. Each cylinder head has a valvetronic assembly – including a motor, control module and position sensor.^[4]

The N73 was superseded by the BMW N74, a twin-turbocharged V12 engine.

Versions

Version	Year	Displacement	Power	Torque	Comp. ratio
N73B60	2003-2008	5,972 cc (364.4 cu in)	327 kW (445 PS; 439 hp) at 6,000 rpm	600 N⋅m (443 lb⋅ft) at 3,950 rpm	11.3:1
N73B68	2003-2016	6,749 cc (411.8 cu in)	338 kW (460 PS; 453 hp) at 5,350 rpm	720 N⋅m (531 lb⋅ft) at 3,500 rpm	11.0:1

N73B60

The 5,972 cc (364.4 cu in) version has a bore of 89 mm (3.50 in) and a stroke of 80 mm (3.15 in).^[5]

Application:

• 2003-2008 E65/E66 760i/760Li
• 2017 Eadon Green Black Cuillin^[6]

N73B68

The 6,749 cc (411.8 cu in) version has a bore of 92 mm (3.62 in)and a stroke of 84.6 mm (3.33 in).

Application:

• 2003-2016 Rolls-Royce Phantom^[7]

See also

• List of BMW engines