Active yaw control

Active Yaw Control (AYC) is an automobile feature designed by Mitsubishi that was introduced in the Japanese Market Mitsubishi Lancer Evolution IV and has been included in certain models of every generation up to and including the current Evolution IX.

AYC is based on a computer controlled rear differential which can actively split torque based on input from various accelerometers in the vehicle. It accomplishes this via two hydraulic clutches which can limit torque on individual axles. This system should not be confused with stability control systems which utilize the braking system of a vehicle by individually braking certain wheels to rotate and slow the car (such as Electronic Brakeforce Distribution). AYC is a performance-oriented system which aims to increase cornering speeds. Starting with the Lancer Evolution VIII, AYC became the SAYC (Super-Active Yaw Control) system which utilized a planetary gearset which could support an even greater torque bias than the previous system.