The BMW N55 is a turbocharged straight-6 petrol engine that began production in 2009. The N55 replaced the N54 and was introduced in the F07 535i 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 B58 engine in 2015, the N55 began to be phased out.
The F80 M3, F82 M4 and F87 M2 Competition are powered by the S55 engine, which is the high performance version of the N55.
Video BMW N55
Design
The main differences between the N55 and its N54 predecessor are the use of a single turbocharger, the addition of variable valve lift and the type of fuel injectors. The N54 uses twin-turbochargers (operating in a parallel configuration), however the N55 uses a single twin scroll turbocharger. Variable valve lift (called Valvetronic by BMW) was introduced on the N55 engine, improving throttle response, low-rev torque, exhaust emissions and increasing fuel economy by 15%. Instead of using piezo-type fuel injectors for the direct injection system, the N55 uses Bosch solenoid-type injectors. 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 (CCM) 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 (RON) 91-98 octane (minimum RON 95 is recommended),
As per the N54, the compression ratio is 10.2:1, the bore is 84 mm (3.3 in), the stroke is 89.6 mm (3.5 in) and the capacity is 2,979 cc (181.8 cu in).
Maps BMW N55
Transmission pairings
A six-speed manual transmission (ZF S6-45) was available with the N55 in some models.
For the automatic transmissions, initially the N55 was used with a ZF 6HP19 six-speed automatic. In 2009, the six-speed automatic began to be replaced by the ZF 8HP45 eight-speed automatic transmission.
In several models (including the 2011 BMW E82 135i and 2013 E82 135is), a Getrag 7-speed Dual-clutch transmission was available.
Models
N55B30M0 (225 kW)
Applications:
- 2009-2017 F10/F11/F07 535i
- 2010-2013 E90/E91/E92/E93 335i
- 2010-2013 E82/E88 135i
- 2010-2017 F25 X3 xDrive35i
- 2011-2013 E70 X5 xDrive 35i
- 2011-2015 F30/F31 335i
- 2011-2014 E71 X6 xDrive 35i
- 2012-2015 E84 X1 xDrive35i
- 2013-2016 F32/F33/F36 435i
- 2014-2018 F15 X5 xdrive 35i
- 2014-present F16 X6 xDrive35i
- 2014-2016 F26 X4 xDrive 35i
N55B30 (235 kW)
Applications:
- 2011-present F06/F12/F13 640i
- 2012-2013 E82/E88 135is
- 2012-2015 F20/F21 M135i
- 2012-2015 F01 740i/Li
N55B30O0 (240 kW)
Applications:
- 2013-2016 F22/F23 M235i
- 2015-2016 F20/F21 M135i LCI
N55HP (250 kW)
Applications:
- 2013-2015 F30 ActiveHybrid 3
N55B30T0 (265 kW)
Applications:
- 2015-2018 F26 X4 M40i
N55B30T0 (272 kW)
Applications:
- 2016-2018 F87 M2
Alpina
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 301 kW (404 hp).
Applications:
- 2013-2017 Alpina F30/F31 B3 Bi-Turbo
- 2013-2017 Alpina F32 B4 Bi-Turbo
- 2014-2017 Alpina F33 B4 Bi-Turbo
324 kW version
Applications:
- 2017-present Alpina F30/F31 B3 S Bi-Turbo
- 2017-present Alpina F32/F33 S B4 Bi-Turbo
S55
The S55 engine is the high performance version of the N55 engine, which replaced the BMW S65 naturally aspirated V8 engine. Differences compared with the N55 include a closed-deck engine block, lightweight crankshaft, strengthened pistons, different valve material, twin turbos, twin fuel pumps, active exhaust and revised intercoolers.
302 kW version
Applications:
- 2018-present F87 M2 Competition
317 kW version
Applications:
- 2014-present F80 M3
- 2014-present F82/F83 M4
331 kW version
Applications:
- 2016-present F80 M3 Competition
- 2016-present F82/F83 M4 Competition
338 kW version
Applications:
- 2018-present F80 M3 CS
- 2017-present F82 M4 CS
368 kW version
This version produces 368 kW (493 hp) and 600 N?m (443 lb?ft), 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).
Applications:
- 2015-present F82/F83 M4 GTS
See also
- List of BMW engines
References
Source of article : Wikipedia
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