929 V6-3.0L DOHC (1993)
Active Exhaust System Actuator: Description and Operation
Variable Exhaust System
PURPOSE
By opening and closing a shutter valve in the tail pipe, system obtains quiet operation while maintaining adequate engine power output.
LOCATION
Shutter valve is in inboard tail pipe. Air control motor is in right rear corner of trunk.
OPERATION
System opens and closes a shutter valve attached to the tail pipe, changing the exhaust path according to engine speed and intake air volume.
When engine speed is 3400 rpm or above with heavy load applied, current flows in motor direction X for approximately 1 second and the motor
limit switch causes the cable to be pulled in direction Y until the shutter valve fully opens.
When engine speed is below 3400 rpm with light load applied, the previous actions are reversed and the shutter valve closes.
