BMW N55

BMW N55 engine
Overview
Manufacturer BMW
Production 2009present
Combustion chamber
Configuration Straight-6
Chronology
Predecessor BMW N54
Successor BMW B58

The BMW N55 is a turbocharged direct injection straight-6 DOHC engine which began production in 2009 and presently (2015) remains in production. It was launched in the F01 535i Gran Turismo.[1] The N55 began to be phased out following the introduction of the B58 engine in 2015.[2]

Compared with its N54 predecessor, the N55 features a single twin-scroll turbo (the N54 uses twin turbos) and variable valve lift (called Valvetronic by BMW).

The F80 M3 and F82 M4 are powered by the S55 engine, which is the high performance version of the N55.

Models

EngineDisplacementPowerTorqueRedlineBoreStrokeCRYear
N55B30M02,979 cc (182 cu in)225 kW (302 hp) @ 5800-6000400 N·m (295 lb·ft) @ 1200-5000700084 mm (3.3 in)89.6 mm (3.5 in)10.22009
N55235 kW (315 hp) @ 5800-6000450 N·m (332 lb·ft) @ 1300-450070002010
N55B30O0240 kW (322 hp) @ 5800-6000450 N·m (332 lb·ft) @ 1300-450070002011
N55HP250 kW (335 hp) @ 5800-6000450 N·m (332 lb·ft) @ 1300-450070002013
N55B30T0265 kW (355 hp) @ 5800-6000465 N·m (343 lb·ft) @ 1350-525070002015
S55B30T0317 kW (425 hp) @ 5500-7300550 N·m (410 lb·ft) @ 1850-550075002015

N55B30M0 (225 kW)

Applications:

N55B30O0 (235 kW)

Applications:

N55B30O0 (240 kW)

Applications:

N55HP (250 kW)

Applications:

N55B30T0 (265 kW)

Applications:

Design

While its N54 predecessor uses parallel twin-turbochargers, the N55 uses a single twin scroll turbocharger.[7][8] BMW has used the term "TwinPower Turbo" to describe both twin-turbo and (single turbocharger) twin-scroll systems. Another difference is that the N55 has variable valve lift (called Valvetronic by BMW).[9]

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.[10]

The N54's gasoline direct injection system uses piezo injectors, also used in the naturally-aspirated N53 (mostly European markets only), the N55's direct injection uses Bosch solenoid-type injectors. The piezo injectors were more expensive and BMW decided they were not worthwhile in North America, in contrast to Europe which they could perform lean burn to reach their full potential.[9]

The engine includes BOSCH MEVD 17.2 engine management, and supports ROZ(RON) 91-98 octane fuel types (recommended RON 95),[11][12] Valvetronic III (variable valve lift control) with double VANOS, direct injection and turbocharging. Turbocharging uses 2 sets of exhaust duct to turn 1 turbine wheel, with cylinders 1-3 and 4-6 combined to form 2 exhaust channels.[13]

The N55 is mated to ZF's 8-speed automatic transmission in most applications such as the 2011 535i and 2013 BMW 740i,[14] and a 6-speed manual is usually available for sedans (excluding the 7-Series, and dropped for the 5 and 6 series for 2015), but not crossovers such as the X3, X5 and X6. The N55 engines in the 2011 BMW 135i and 2013 BMW 135is are mated to Getrag 7-speed Dual-clutch transmission or a 6-speed manual transmission.[15][16]

While having the same displacement and peak power output as the N54, the N55 is 15% more fuel efficient, has lower emissions,[17] less turbo lag and better low-rev torque.[9][18]

S55

BMW S55

The S55 engine is the high performance version of the N55 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.[19][20]

S55B30T0 (317 kW)

See also

References

External links

This article is issued from Wikipedia - version of the Monday, February 01, 2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.