Manual: 2011/2012 911

Page: 53

Porsche Traction Management (PTM)
With PTM, the engine power is variably distributed to the front and rear wheels.

Power distribution between the front and rear axles is performed by a map-conrolled multipledisc clutch.

Distribution of the engine power also depends on the difference in wheel speed between the two axles.

The multiple-disc clutch always delivers sufficient drive power to the front wheels to ensure optimum propulsion even on an unfavorable road surface.

In combination with the Porsche Stability Management (PSM), the PTM ensures optimum handling and high driving stability.

Inappropriate Driving Style and Speed

The increased control that is provided should not induce you to take greater risks with your safety.

The limits dictated by the laws of physics cannot be overcome, even with PTM.

The risk of accidents due to inappropriate speed cannot be reduced, even by PTM.

The driver bears the responsibility for all driving maneuvers.

  • Adapt your driving style to the prevailing road and weather conditions.
  • Obey all traffic laws.

Dynamometer testing procedure
Some U.S. states and Canadian provinces conduct emissions inspection/maintenance testing involving the use of two-wheel dynamometer.

A two-wheeled dynamometer is a treadmill type device upon which a single axle of the car, the driving axle of the vehicle, rotates to simulate vehicle operation on the road while the vehicle remains stationary.

Your vehicle has a full-time four-wheel drive system which cannot be disabled. Severe damage to the powertrain can result if tested on a two-wheel dynamometer.

Unexpected Movement of the Vehicle

Severe damage to the powertrain can result if tested on a two-wheel dynamometer.

  • Do not test your vehicle on a two-wheel dynamometer.
  • Advise the emission station of this warning before testing the vehicle.

Brake tests
Brake tests must be performed only on roller test stands.

The ignition must be off.
The following limit values must not be exceeded on roller test stands:
– Testing speed 5 mph (8 km/h)
– Test duration 20 seconds

Handbrake tests
Handbrake tests on the roller test stand must only be carried out with the ignition switched off.

Balancing wheels on the vehicle
During finish balancing of the wheels, the vehicle must be hoisted and all the wheels able to rotate freely.

Towing

  • Please see the chapter "TOWING" on page 242.

Wheels/Tires
The PTM control unit is adapted to the approved tire sizes. The use of non-approved tire sizes may lead to deviations in wheel speeds and it may influence handling or result in the PTM switching off.