Functional description, see BMW Technology:

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SBT number:

• 11 05 04 098
  

Overview of functions

On the M57TU TOP, the charge-air pressure is controlled with three controllers:

• Turbine control flap
  
• Compressor bypass plate
  
• Wastegate valve
  

The turbine control flap controls the distribution of the exhaust flow between the large and small turbines. The adjustment is pneumatic by means of an electropneumatic exhaust backpressure transducer and a partial-vacuum canister.

The compressor bypass plate opens the bypass around the small compressor at high loads and engine speeds. This enables the high air masses created by the large compressor to flow to the charge air cooler without hindrance. The adjustment is pneumatic by means of an electropneumatic switch over valve and a partial-vacuum canister.

The wastegate valve limits the maximum charge-air pressure by diverting excess exhaust past the large turbine into the exhaust system. The adjustment is pneumatic by means of an electropneumatic exhaust backpressure transducer and a partial-vacuum canister.

Diagnosis instructions

The three controllers can be activated via diagnosis. The engine must be running to create the necessary partial vacuum.