BMW N73

BMW N73 engine
BMW N73 engine
Overview
Manufacturer	BMW
Production	2003 - 2016
Layout
Configuration	DOHC 60° V12
Chronology
Predecessor	BMW M73
Successor	BMW N74

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

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

Compared with its M73 predecessor, the N73 also has DOHC, variable valve timing (called double-VANOS by BMW) and variable valve lift (called Valvetronic by BMW).^[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 6500 rpm.

The N73 engine also featured BMW’s ‘Valvetronic’ system, which varied intake valve opening lift between 0.3 mm and 9.85 mm, 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The N73 was superseded by the N74, a 6 litre twin-turbocharged V12 engine.

Models

Engine	Year	Displacement	Power	Torque	CR
N73B60	2003-2008	5,972 cc (364 cu in)	327 kW (439 bhp) @ 6000 rpm	600 N⋅m (443 lb⋅ft) @ 3950 rpm	11.3
N73B68	2003-2016	6,749 cc (412 cu in)	338 kW (453 bhp) @ 5350 rpm	720 N⋅m (531 lb⋅ft) @ 3500 rpm	11.0

N73B60

The 6.0 litre version has a bore of 89.0 mm (3.5 in) and a stroke of 80.0 mm (3.1 in).^[5]

Application:

2003-2008 E65/E66 760i/760Li

N73B68

The 6.75 litre version has a bore of 92.0 mm (3.6 in) and a stroke of 84.6 mm (3.3 in).