BMW N55, Manual, Page: 7 / 100

Oil supply:
• An enhanced and simplified oil circuit design is used.
• The inlet pipe, oil deflector, and oil collector are combined in one component.
• Oil pump uses a Duroplast slide valve and it is electronically controlled based on
a characteristic map within the engine management.
Forced induction:
• The N55 uses a single twin scroll turbocharger with vacuum operated,
electronically controlled wastegate valve.
• The electric diverter valve is intergraded into the turbocharger compressor housing.
Air intake and exhaust system:
• Air intake system is similar in configuration as the N54 with the exception of the
intake manifold and the use of a single turbo.
• The intercooler is an air to air type mounted in the lower area of the front bumper
cover.
• The exhaust system uses no underbody catalytic converter.
Vacuum system:
• The N55 engine has a two-stage vacuum pump as on the N54.
• The vacuum system has the vacuum reservoir built into the cylinder head cover.
Fuel injection:
• HDE (high pressure fuel injection) system is installed on the N55.
• The HDE system uses solenoid valve fuel injectors instead of the piezoelectric
type used on HPI.
• The high pressure pump and pressure sensors are similar in design and function
in both the HDE and HPI systems.
Digital Motor Electronics (DME):
• The DME is mounted on the intake manifold and cooled by intake air.
• The location of the DME facilitates the installation of the N55 engine in several
current BMW platforms/models.
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N55 Engine