BMW N55


BMW N55 is a turbocharged straight-six petrol engine that began production in 2009. The N55 replaced the BMW N54 engine and was introduced in the BMW [5 Series Gran Turismo|F07 5 Series Gran Turismo].
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.
Following the introduction of the BMW B58 engine in 2015, the N55 began to be phased out.
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

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. Valvetronic is claimed to improve throttle response, low-rev torque, exhaust emissions and to reduce fuel consumption by 15%. 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.
The exhaust manifold design, called Cylinder-bank Comprehensive Manifold by BMW, aims to reduce the pressure fluctuations to reduce throttle lag and exhaust back-pressure. The twin-scroll turbocharger uses 2 sets of exhaust duct to turn 1 turbine wheel, with cylinders 1–3 and 4–6. The engine management system is Bosch MEVD 17.2, and compatible fuels are ROZ 91–98 octane,
The compression ratio is 10.2:1, the bore is, the stroke is and the displacement is, all of which are unchanged from its predecessor, the N54.

Versions

N55B30M0

Applications:
  • 2009–2017 F10/F11/F07 535i
  • 2010–2013 BMW [3 Series |E90/E91/E92/E93] 335i
  • 2010–2013 E82/E88 135i
  • 2010–2017 F25 X3 xDrive35i
  • 2011–2013 E70 X5 xDrive 35i
  • 2011–2015 F30/F34/F31 335i
  • 2011–2014 E71 X6 xDrive 35i
  • 2012–2015 E84 X1 xDrive35i
  • 2013–2016 BMW [4 Series |F32/F33/F36] 435i
  • 2014–2018 F15 X5 xDrive 35i
  • 2014–2019 F16 X6 xDrive35i
  • 2014–2016 F26 X4 xDrive 35i

    N55B30

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

    N55B30T0

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

301 kW version

The N55R20A is Alpina's initial version of the N55, producing. The twin turbocharger system of the N54B30 is used, replacing the twin-scroll charging system originally applied.
Applications:
  • 2013–2017 [Alpina B3 |Alpina F30 B3] Bi-Turbo
  • 2013–2017 Alpina F33/F34 B4 Bi-Turbo

    324 kW version

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

    332 kW version

Application:
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.

– version

Applications:
  • 2020–2021 F87 M2 CS Racing

    , version

Applications:
  • 2019–2021 F87 M2 Competition

    version

Applications:
Applications:
  • 2016–2018 F80 M3 with Competition package
  • 2016–2020 F82/F83 M4 with Competition package
  • 2020–2021 F87 M2 CS

    version

Applications:
  • 2018 F80 M3 CS
  • 2017–2020 F82 M4 CS

    version

This version produces and, 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 to.
Applications:
  • 2015–2016 F82 M4 GTS
  • 2017 F82 M4 DTM Champion Edition