Exhaust Flap Damper Control

The silencer incorporates a damper flap that is designed to reduce exhaust noise at idle, low RPM and while coasting. Control of the flap is an output function of the MS41.1 system. Components of the system include:
- Exhaust flap with vacuum actuator Switching solenoid
- Vacuum reservoir
- Check valve

Exhaust Backpressure:

Exhaust Noise:

OPERATION
The MS41.1 Control Module will power the switching solenoid and apply vacuum to the exhaust flap actuator for the following conditions:
- Engine idle - up to 2,500 RPM
- Engine decel

This will close the flap allowing additional damping of the exhaust to take place.

The solenoid will switch OFF when accelerating above 2,500 RPM. The vacuum is vented from the flap actuator and the flap opens. This allows the M52 engine to make maximum use of the backpressure effect for improved torque response.