When the system determines it's needed, PTM diverts engine power and torque to the front axle in · millisecond cycles. Particularl

When the system determines it's needed, PTM diverts engine power and torque to the front axle in millisecond cycles. Particularly at speed, the driver feels the significant stability. PTM instantly detects dynamic changes in driving conditions, avoiding wheelspin. The system determines how fast the driver is accelerating and how much throttle is being applied before the engine is even able to react. PTM closes the multiple-plate clutch to prevent wheelspin. This translates to quick, smooth and lightning fast launches with equal traction at all four wheels. In the wet, the Turbo reaches its rear-axle traction limit quickly, thanks to the car's huge amounts of torque. When accelerating on a wet surface, PTM intervenes more aggressively, feeding more torque more quickly to the front wheels. Similarly, since PTM reads steering-angle information as well as wheelslip, the system recognizes oversteer and understeer and compensates by diverting more stabilizing power to the front wheels or rear wheels as needed. Given that PTM reacts in milliseconds, as the skilled driver corrects the steering, the PTM recognizes that, too, and readjusts power distribution before the driver is aware it is happening. Multiple-plate clutch with magnetic control Unlike other makers’ all-wheel drive systems with viscous couplings, PTM relies on the instant response of an electronically controlled, electro-magnetic multiplate clutch pack to distribute engine torque to the front and rear wheels as conditions demand. Magnets operate a master clutch with three discs. The discs are connected to one another by a mechanical reinforcement element, which actuates the main clutch. The main clutch is comprised of eight sets of friction discs. Given that the Turbo Coupe's front tires lose traction on a dry road at about 221 lb.-ft. (300 Nm) of torque, the clutch's capacity of 295 lb.-ft. (400 Nm) is more than sufficient. The multiple-plate clutch runs in an oil bath integrated in the housing of the front-axle differential, and features its own oil circuit, complete with a separate circulation pump. The special automatic transmission fluid used has a recommended service interval of 56,000 miles (90,000 km). Optimized braking and stability The dedicated computer which controls PTM is apprised of wheel speed, lateral and straight-ahead acceleration and steering angle via a CAN-bus network with other systems. Among those systems is Porsche Stability Management (PSM), which is standard on the Turbo Coupe. Besides helping ensure stability, PSM boasts new functions. Critical among them is pre-loading the brakes to help shorten stopping distances in an emergency. Whenever the driver lifts off the gas pedal abruptly the system instantly pumps brake fluid from the hydraulic PSM control unit to the brake calipers. This has the pads already touching the rotors by the time the driver's foot hits the brake pedal. The result is less reaction time for quicker stops.