Audi A3 Sportback, Сервисная инструкция, Страница: 29 / 60

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Exhaust turbocharger/manifold module
Due to the constraints on available space, a modular package comprising an exhaust manifold and turbine
housing has been developed for the respective longitudinal and transverse mounting drive train variants.
Special emphasis was placed on implementing a service solution for the easy removal and installation of the
exhaust manifold and the integration of a close-coupled catalytic converter.
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Crankcase breather
connection
Coolant flow to radiator or
from auxiliary water pump
ACF connection
Pressurised oil inlet
Turbocharger divert air valve
N249
Coolant inlet from engine
block
The turbine shaft mounting is integrated in the compressor housing. The air intake includes connections for
crankcase and ACF ventilation. A specially adapted silencer for the reduction of pressure pulsation noises is
attached to the pressure connection.
The required boost pressure is set by means of charge pressure control solenoid valve N75 (on the 1.8 turbo it
functions as an overpressure control unit) and a so-called "wastegate". An electrical turbocharger divert air
valve N249 is used to avoid "overbraking" of the turbocharger turbine when the engine is in overrun with the
throttle valve closed and boost pressure still present.
The charge pressure control solenoid valve N75 and the turbocharger divert air valve N249 are located on the
turbocharger.