BMW N74

The BMW N74 is a twin-turbo V12 petrol engine which replaced the N73 and has been produced since 2008. Production will end in 2023.[1] It is BMW's first turbocharged V12 engine and is also used in several Rolls-Royce models.

BMW N74 engine
Overview
Production2008–present
Layout
Configuration60° V12
Displacement6.0–6.7 L (366–409 cu in)
Block materialAluminium
Head materialAluminium
ValvetrainDOHC with VVT
Combustion
TurbochargerTwin-turbo
Fuel typePetrol
Chronology
PredecessorBMW N73
Cutaway view of N74

Design

Compared with its naturally aspirated BMW N73 predecessor, the N74 features twin-turbochargers. The turbochargers are located on the outside of the engine and use a boost pressure of 11.6 psi (0.8 bar).[2] In its base configuration, the engine has a compression of and a specific fuel consumption of 245 g·kW−1·h−1[3]

As per its predecessor, the N74 has direct injection, DOHC and variable valve timing (called double-VANOS by BMW).[4][5] However, the N74 does not have variable valve lift (called Valvetronic by BMW).[6]

The N74 marked BMW's first use of an 8-speed automatic transmission, in the form of the ZF 8HP90.[2]

Versions
EngineDisplacementPowerTorqueYear
N74B60[3]5,972 cc (364.4 cu in)400 kW (536 hp)
at 5,250 rpm		750 N⋅m (553 lb⋅ft)
at 1,500–5,000 rpm		2009–present
N74B666,592 cc (402.3 cu in)420 kW (563 hp)
at 5,250 rpm		780 N⋅m (575 lb⋅ft)
at 1,500–5,000 rpm		2009–present
465 kW (624 hp)
at 5,600 rpm		800 N⋅m (590 lb⋅ft)
at 1,500–5,500 rpm		2013–present
442 kW (593 hp)
at 5,250 rpm		840 N⋅m (620 lb⋅ft)
at 1,500 rpm		2016–present
N74B66TU449 kW (602 hp)
at 5,500 rpm		800 N⋅m (590 lb⋅ft)
at 1,500 rpm		2016–present
N74B686,749 cc (411.8 cu in)420 kW (563 hp)
at 5,250 rpm		900 N⋅m (664 lb⋅ft)
at 1,500 rpm		2017-present

N74B60

This initial version of the N74 has a bore of 89 mm (3.5 in) and a stroke of 80 mm (3.1 in). The redline is 7000 rpm and the compression ratio is 10.0:1.[7]

Applications:

N74B66
N74 in Rolls Royce Ghost

The N74B66 is an enlarged version of the N74B60, due to a stroke of 88 mm (3.5 in). The redline is 7000 rpm and the compression ratio is 10.0:1. It produces up to 465 kW (624 hp) and is used in the Rolls-Royce Ghost.[2]

YearApplicationPower outputTorque
2010–2020Rolls-Royce Ghost420 kW (563 hp)780 N⋅m (575 lb⋅ft)
2014–2020Rolls-Royce Ghost V-Specification442 kW (593 hp)780 N⋅m (575 lb⋅ft)
2014–presentRolls-Royce Wraith465 kW (624 hp)800 N⋅m (590 lb⋅ft)
2015–presentRolls-Royce Dawn420 kW (563 hp)820 N⋅m (605 lb⋅ft)

N74B66TU

Applications:

N74B68

The 6.75 litre version was introduced in the 2018 Rolls-Royce Phantom. It is also used in the Rolls-Royce Cullinan, built on the same platform as the new Phantom.[12]

Applications:

References
  1. "BMW's biggest engine - the V12 - is safe until 2023". www.topgear.com. Retrieved 4 April 2019.
  2. "2010 BMW 760Li – Second Drive – Car Reviews". www.caranddriver. Retrieved 12 March 2017.
  3. Hans-Stefan Braun, Thomas Brüner, Klaus Hirschfelder, Uwe Hoyer, Horst Kellerer, Johann Schopp, Christian Schwarz: Der neue Zwölfzylinder-Ottomotor von BMW, in MTZ - Motortechnische Zeitschrift, November 2009, Volume 70, Issue 11, pp. 848
  4. "Information on N74 engines". www.bmwheaven.com. Retrieved 11 August 2017.
  5. 25 years of BMW 12-cylinder engines: setting new standards in the luxury class. Munich, Germany: BMW Corporate Communications. October 2012. Retrieved 11 August 2017.
  6. "BMW N74 engine". www.australiancar.reviews. Retrieved 12 March 2017.
  7. "BMW N73 and N74 V12 Engines". www.unixnerd.demon.co.uk. Retrieved 11 August 2017.
  8. "BMWBLOG Road Review: 2013 BMW 760Li – The Power of 12". www.bmwblog.com. Retrieved 11 August 2017.
  9. "The new BMW M760Li xDrive". www.bmwgroup.com. Retrieved 11 August 2017.
  10. "Watch BMW's twin turbo all wheel drive V12 G11 M760li hustle to 162 miles per hour". www.bimmerboost.com. Retrieved 11 August 2017.
  11. "BMW N74B66TU / M760li xDrive". www.drive2.ru (in Russian). Retrieved 11 August 2017.
  12. "RealOEM.com - Online BMW Parts Catalog". www.realoem.com. Retrieved 20 November 2017.
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