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 | |
|---|---|
 Model of an N74 | |
| Overview | |
| Production | 2008–present |
| Layout | |
| Configuration | 60° V12 |
| Displacement | 6.0–6.7 L (366–409 cu in) |
| Cylinder block material | Aluminium |
| Cylinder head material | Aluminium |
| Valvetrain | DOHC with VVT |
| Combustion | |
| Turbocharger | Twin-turbo |
| Fuel type | Petrol |
| Chronology | |
| Predecessor | BMW N73 |
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 ratio of 10:1 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
| Engine | Displacement | Power | Torque | Year |
|---|---|---|---|---|
| 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 |
| N74B66 | 6,592 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 | ||
| N74B66TU | 449 kW (602 hp) at 5,500 rpm |
800 N⋅m (590 lb⋅ft) at 1,500 rpm |
2016–present | |
| N74B68 | 6,750 cc (411.9 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:
- 2008–2015 F01/F02/F03 760i/760Li[8]
N74B66
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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]
| Year | Application | Power output | Torque |
|---|---|---|---|
| 2010–2020 | Rolls-Royce Ghost | 420 kW (563 hp) | 780 N⋅m (575 lb⋅ft) |
| 2014–2020 | Rolls-Royce Ghost V-Specification | 442 kW (593 hp) | 780 N⋅m (575 lb⋅ft) |
| 2014–present | Rolls-Royce Wraith | 465 kW (624 hp) | 800 N⋅m (590 lb⋅ft) |
| 2015–present | Rolls-Royce Dawn | 420 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:
- 2017-present Rolls-Royce Phantom VIII
- 2018-present Rolls-Royce Cullinan
- 2021-present Rolls-Royce Ghost
References
- ^ "BMW's biggest engine - the V12 - is safe until 2023". www.topgear.com. Retrieved 4 April 2019.
- ^ a b c "2010 BMW 760Li – Second Drive – Car Reviews". www.caranddriver. Retrieved 12 March 2017.
- ^ a b 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
- ^ "Information on N74 engines". www.bmwheaven.com. Retrieved 11 August 2017.
- ^ 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.
- ^ "BMW N74 engine". www.australiancar.reviews. Retrieved 12 March 2017.
- ^ "BMW N73 and N74 V12 Engines". www.unixnerd.demon.co.uk. Retrieved 11 August 2017.
- ^ "BMWBLOG Road Review: 2013 BMW 760Li – The Power of 12". www.bmwblog.com. Retrieved 11 August 2017.
- ^ "The new BMW M760Li xDrive". www.bmwgroup.com. Retrieved 11 August 2017.
- ^ "Watch BMW's twin turbo all wheel drive V12 G11 M760li hustle to 162 miles per hour". www.bimmerboost.com. Retrieved 11 August 2017.
- ^ "BMW N74B66TU / M760li xDrive". www.drive2.ru (in Russian). Retrieved 11 August 2017.
- ^ "RealOEM.com - Online BMW Parts Catalog". www.realoem.com. Retrieved 20 November 2017.