The BMW N55 is a turbocharged straight-six petrol (gasoline) engine that began production in 2009. The N55 replaced the BMW N54 engine and was introduced in the F07 5 Series Gran Turismo.

BMW N55
Overview
Production2009–2021
Layout
ConfigurationStraight-6
Displacement3.0 L (2,979 cc)
Cylinder bore84 mm (3.3 in)
Piston stroke89.6 mm (3.5 in)
Cylinder block materialAluminium
Cylinder head materialAluminium
ValvetrainDOHC, with VVT & VVL
Valvetrain drive systemChain
Compression ratio10.2:1
RPM range
Max. engine speed7,000 RPM
Combustion
TurbochargerSingle BorgWarner twin-scroll with Intercooler
ManagementBosch MEVD 17.2
Fuel typePetrol
Chronology
PredecessorBMW N54
SuccessorBMW B58

The N55 was BMW's first straight-six engine to use a twin-scroll turbocharger. It also won three straight Ward's 10 Best Engines awards in 2011–2013.[1]

Following the introduction of the BMW B58 engine in 2015, the N55 began to be phased out.[2]

The BMW S55 engine is a high performance version of the N55 made by BMW M GmbH, which is used by the F80 M3, F82 M4 and F87 M2 Competition/CS.

Design

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The main differences between the N55 and its N54 predecessor are the use of a single turbocharger, the addition of Valvetronic and the type of fuel injectors. Whilst the N54 used a twin-turbo arrangement, the newer N55 uses only a single twin scroll turbocharger.[3][4] Valvetronic (variable valve lift)[5] is claimed to improve throttle response, low-rev torque, exhaust emissions and to reduce fuel consumption by 15%.[6][5][7] The direct injection system uses solenoid-type injectors, instead of the piezo-type fuel injectors used by its N54 predecessor. The piezo injectors were more expensive and BMW decided they were not worthwhile outside of Europe, because the potential benefits of lean-burn operation could not be fully realised.[5]

The exhaust manifold design, called Cylinder-bank Comprehensive Manifold (CCM) by BMW, aims to reduce the pressure fluctuations to reduce throttle lag and exhaust back-pressure.[8] The twin-scroll turbocharger uses 2 sets of exhaust duct to turn 1 turbine wheel, with cylinders 1–3 and 4–6.[9] The engine management system is Bosch MEVD 17.2, and compatible fuels are ROZ (RON) 91–98 octane (minimum RON 95 is recommended),[10][11]

As per the N54, the compression ratio is 10.2:1, the bore is 84.0 mm (3.31 in), the stroke is 89.6 mm (3.53 in) and the displacement is 2,979 cc (181.8 cu in).

Versions

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Version Power Torque Redline Years
N55B30M0 225 kW (302 bhp)
at 5,700–5,800 rpm
400 N⋅m (295 lb⋅ft)
at 1,200–5,000 rpm
7,000 rpm 2009–2019
N55B30 235 kW (315 bhp)
at 4,505–6,000 rpm
450 N⋅m (332 lb⋅ft)
at 1,300–4,500 rpm
2011–present
N55B30O0 240 kW (322 bhp)
at 4,505–6,000 rpm
2014–2016
N55HP 250 kW (335 bhp)
at 4,505–6,000 rpm
2013–2015
N55B30T0 265 kW (355 bhp)
at 5,255–6,000 rpm
465 N⋅m (343 lb⋅ft)
at 1,350–5,250 rpm
2015–present
272 kW (365 bhp)
at 6,500 rpm
500 N⋅m (369 lb⋅ft)
at 1,450–4750 rpm
Alpina 301 kW (404 bhp)
at 5,500–6,250 rpm
600 N⋅m (443 lb⋅ft) at
3,000–4,000 rpm
2013–2017
324 kW (434 bhp)
at 5,500–6250 rpm
660 N⋅m (487 lb⋅ft) at
3,000–4,000 rpm
2017–present
332 kW (445 bhp)
at 5,500–6,250 rpm
680 N⋅m (502 lb⋅ft) at
3,000–4,500 rpm
2018–present

N55B30M0

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Applications:

N55B30

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Applications:

N55B30O0

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Applications:

N55HP

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Applications:

  • 2013–2015 F30 ActiveHybrid 3
  • 2011–2016 F10 ActiveHybrid 5

N55B30T0

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Applications:

  • 2016–2018 F87 M2 — 272 kW (365 bhp)
  • 2015–2018 F26 X4 M40i — 265 kW (355 bhp)

Alpina

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Biturbo engine by Alpina based on the N55B30M0. The crankcase is of a different design and specially cast by BMW for Alpina.[16]

301 kW version

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The N55R20A is Alpina's initial version of the N55, producing 301 kW (404 bhp). The twin turbocharger system of the N54B30 is used, replacing the twin-scroll charging system originally applied.

Applications:

324 kW version

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Applications:

  • 2017–present Alpina F30/F31 B3 S Bi-Turbo
  • 2017–present Alpina F32/F33 B4 S Bi-Turbo

332 kW version

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Application:

S55 engine

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BMW S55 engine
 
Layout
ConfigurationStraight-6
Displacement2,979 cc (182 cu in)
Cylinder bore84 mm (3.3 in)
Piston stroke89.6 mm (3.53 in)
Cylinder block materialAluminium
ValvetrainDOHC, with VVT & VVL
RPM range
Max. engine speed7,600 RPM
Combustion
TurbochargerTwin-turbo
Fuel typePetrol
Chronology
PredecessorBMW S54
SuccessorBMW S58

The S55 engine is the high performance engine developed from the N55 by BMW M. It was introduced in the F80 M3 and F82 M4 replacing the BMW S65 naturally aspirated V8 engine used in the previous generation M3 and was later used in the F87 M2 Competition/CS.

Differences compared with the N55 include a closed-deck engine block, lightweight crankshaft, different crankshaft bearings, strengthened pistons/rods, different springs/valve material, twin turbos, twin fuel pumps, active exhaust, revised cooling system and intercoolers.[18][19]

205 kW (275 bhp) – 268 kW (359 bhp) version

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Applications:

  • 2020–present F87 M2 CS Racing[20]

302 kW (405 bhp), 550 N⋅m (410 lb⋅ft) version

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Applications:

317 kW (425 bhp) version

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Applications:

331 kW (444 bhp) version

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Applications:

  • 2016–2018 F80 M3 with Competition package[23]
  • 2016–2020 F82/F83 M4 with Competition package[24]
  • 2020–2021 F87 M2 CS[25]

338 kW (453 bhp) version

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Applications:

368 kW (493 hp) version

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This version produces 368 kW (493 hp) and 600 N⋅m (443 lb⋅ft),[26] due to the use of a water injection system. Three water injectors are used to lower the temperature of the air in the intake manifold, allowing the boost pressure to be increased from 17.2 psi (1.19 bar) to 21.6 psi (1.49 bar).[27][28]

Applications:

  • 2015–2016 F82 M4 GTS
  • 2017 F82 M4 DTM Champion Edition[29]

See also

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References

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  1. ^ "Ward's 10 Best Engines Winners, 1995–2012". wardsintelligence.informa.com. 5 January 2012. Archived from the original on 11 March 2012. Retrieved 21 December 2021.
  2. ^ "BMW University Technical Training- B58 Engine" (PDF). Bimmerfile.com.
  3. ^ Ryan ZumMallen. "Pop The Hood: Inside the Innovative N55 Engine in the BMW 335i". Automedia.com. Archived from the original on 2012-08-04. Retrieved 2012-08-13.
  4. ^ "BMW unveils single turbo N55 six-cylinder engine for new 5-series GT". Motorauthority.com. 26 May 2009.
  5. ^ a b c "BMW's Newest I-6 Better, Not Bigger". Wardsauto.com.
  6. ^ "BMW N54 and N55 Six Cylinder Turbocharged Engines". Unixnerd.demon.co.uk. Archived from the original on 20 February 2020. Retrieved 20 December 2017.
  7. ^ "2011 BMW 335i Sedan". Caranddriver.com.
  8. ^ "The NEW ///M Motor in Depth". Bimmerfile.com. May 2009.
  9. ^ "Turbocharging Technology (F30)" (PDF). Kneb.net. Archived from the original (PDF) on 2015-06-15.
  10. ^ "F30 powertrain" (PDF). bmwuniversity.com. Archived from the original (PDF) on 2014-06-03.
  11. ^ "Engine Electronics IPO's (F01-02)" (PDF). Kneb.net. Archived from the original (PDF) on 2014-06-03.
  12. ^ "Six-Cylinder 2012 BMW 640i Coupe Priced from $74,475, Convertible from $81,975". Blog.caranddriver.com. Archived from the original on 2011-09-25. Retrieved 2011-09-24.
  13. ^ "BMW 135is Coupe – Model Overview". Bmwusa.com.
  14. ^ "2012 BMW M135i". Autoblog.com. 24 July 2012.
  15. ^ "BMW's M135i is much better than it looks". Ausmotive.com.
  16. ^ Gratton, Ken (2016-12-23). "The Alpina philosophy – motoring.com.au". motoring.com.au. Retrieved 2016-12-24.
  17. ^ "Road Vehicle Descriptor (RVD1)". rvcs-prodweb.dot.gov.au. Retrieved 2016-11-24.
  18. ^ "F80 M3 / F82 M4 Complete Technical Docs (With S55 Engine Guide)". Bimmerpost.com.
  19. ^ "Meet The New S55 Engine". Bmwblog.com. 25 September 2013.
  20. ^ "BMW M2 CS Racing makes its North American debut". autodevot.com. Retrieved 2020-02-02.
  21. ^ "BMW M2 Competition specs leaked". MotorMag.com.au. Retrieved 2018-04-10.
  22. ^ a b "2013 BMW M3 F80 specifications". Carfolio.com. Retrieved 21 July 2017.
  23. ^ "BMW M3 Sedan – BMW Australia". Bmw.com.au. Retrieved 30 May 2018.
  24. ^ "BMW M4 Coupé – BMW Australia". Bmw.com.au. Archived from the original on 2 May 2018. Retrieved 30 May 2018.
  25. ^ "444-Horsepower M2 CS Can Be Had With 3 Pedals". BimmerLife. 2019-11-06. Retrieved 2019-12-31.
  26. ^ "2015 BMW M4 GTS specifications". Carfolio.com. Retrieved 30 December 2017.
  27. ^ "First Drive Review – 2016 BMW M4 GTS". Caranddriver.com. Retrieved 30 December 2017.
  28. ^ "The 2016 BMW M4 GTS is a street-legal water-injected track monster, and it's coming to the US". Autoweek.com. Retrieved 30 December 2017.
  29. ^ "BMW M4 DTM Champion Edition marking Marco Wittmann's 2016 DTM championship title". BMW PressClub Global. Retrieved 31 October 2019.