BMW N73 and N74 V12 Engines

BMW N73 V12 engine

N74 6.6 turbo in a Rolls Royce.


The N73 replaced the 5.4 litre M73TU engine in 2003. The new engine was a 6.0 and was used in the E65 / E66 760Li. A 6.8 litre version was used by Rolls Royce.

In 2009 the turbocharged N74 replaced the N73 and was used in the new F01 760i. A 6.6 litre version powered several Rolls Royce models from 2013.

BMW N73 V12 engine

N73 6.0 V12.


The original M70 V12 entered production in 1987 and didn't change much during it's 16 year production life. It never incorporated the technologies used in other BMW engines from the same period. So the N73 was a big jump forwards in that regard. It finally used four valves per cylinder and one coil per cylinder.

The timing chain was completely different from the M70 series. For a start there were two, one for each bank. Each chain drove both camshafts, many older BMWs used the chain to drive just one and had a second chain to link the two camshafts. The engine used a forged crankshaft and the same snapped conrod technology pioneered on the M60 V8.

Double VANOS was used to give variable valve timing and Valvetronic operation (explanation here) controlled the valve lift and replaced the throttle plate.

Direct fuel injection into the cylinder was used and the fuel system could run at up to 120 bar pressure (1750psi). All of this combined to make a far more fuel efficient engine than the M70 with much lower emissions.

In many ways the replacement N74 engine is like a pair of N55s in one crank case. The N74's big difference was that it had twin turbos, one big Garrett unit per side that ran around 10psi of boost. The turbos had their own cooling system and like everything else were computer controlled. To account for the turbos the compression ratio was lowered from the N73's 11.3:1 to 10:1.

The G01 M760i uses an M-Performance 6.6 version of the N74 producing around 600bhp. It has a more rigid block and double bolted main bearings. This version also has iron-coated aluminum pistons, forged connecting rods and crankshaft. It has two mono-scroll turbochargers in a compact arrangement on the outside of the block, not the inside of the valley as on some recent V8s. The turbos have high levels of compressor and turbine efficiency and their positioning provides the ideal platform for short, straight and flow-efficient connections between the exhaust ports and turbos. Two air-to-water intercoolers cool the maximize the density of the intake air. An extra water pump feeds the separate intercooler coolant circuit, whose air-to-water heat exchangers are now positioned directly on the intake manifold for the first time. The fuel injection operated at up to 2900psi.

BMW N73 V12 engine

N74 6.0 V12 turbo.


Code Size Power
Made Bore x
Timing Weight
VANOS Used in
N73 6.0 445 @ 6000 441 @ 3950 74.2 73.5 2002-08 89x80 Chain 240 Dual +
E65 760Li
N74 6.0
540 @ 5250
560 @ 5250
600 @ 5500
550 @ 1500-5000
580 @ 1500-5000
590 @ 1500-5000
2009 on 89x80
Chain 240 Dual F01 760Li
RR Ghost


BMW N73 V12 engine

N73 6.0 in an E65 760Li.


These have so many technologies and systems that I just hope the onboard diagnostics are superb. Any repair could get very expensive.

These will suffer the normal problem with direct injection engines of carbon deposits on the backs of the valves. You'll likely need to remove the intake manifolds every 40k miles to clean the intake ports.

The problems of other recent petrol turbos such as the N54 / N55 can be expected on the N74 too. So lots of under hood heat to deal with, blocked crankcase breathers, high pressure fuel pump failures, etc.


BMW N74 6.6 V12 engine

N74 6.6 M-Performance engine from a G01 M760i.