BMW has just taken the wraps off an advanced torque vectoring system that promises to improve both the agility and stability of its four-wheel drive models. Called Dynamic Performance Control, the new system is an evolution of BMW’s xDrive system, but adds a series of additional electro-magnetic clutches, in a modified rear differential housing that allow power to be juggled between the individual rear wheels as well as between the front and rear axles. Dynamic Performance Control works in conjunction with sensors in the anti-lock braking system that measure steering angle, yaw rates, road speed and torque developed by the engine. Essentially, it directs drive to where it can be used most effectively in an operation not dissimilar to that of a traditional locking differential on a rear-wheel-drive car. If the car understeers, xDrive will redirect more drive to the rear wheels and, if required, the Dynamic Performance Control system will then load up the outside rear wheel with the balance of power, providing an additional turning moment beyond that generated by the steering wheels. During oversteer, it reverses the action, sending the majority of drive through the front wheels and, if necessary, increasing torque to the inside rear wheel to stabilise the car during cornering. Both processes are explained in BMW's images, which you'll find in our gallery. Unlike similar systems developed by rival car makers, BMW’s Dynamic Performance Control operates both under load and on the overrun, meaning the car continues to be stabilised even when the driver steps off the throttle mid-corner. The new system adds 12kg to the weight of the car, but it is concentrated low down in the chassis so as not to affect handling to any great degree.