The optional Porsche Doppelkupplung (PDK), with both manual gearshift and an automatic mode, enables smooth gear changes with no interruption in the flow of power. This results in significantly faster acceleration and increased fuel efficiency, without having to sacrifice the ease of automatic transmission. In total, PDK has seven gears at its disposal. Gears 1 to 6 have a sports ratio and top speed is reached in 6th gear. The 7th gear has a long ratio and increases fuel efficiency even further.
PDK is like having two gearboxes in one and thus requires two clutches – designed as a double wet clutch transmission.
This double clutch provides an alternating, non-positive connection between the gearbox and the engine by means of two separate input shafts (input shaft 1 is nested inside the hollowed-out input shaft 2).
The flow of power from the engine is only ever transmitted through one clutch at a time, while the next gear is preselected by the second clutch. During a gear change, a conventional shift no longer takes place. Instead, one clutch simply opens and the other closes at the same time. Gear changes therefore take place within a few hundredths of a second.
Clutch 1 controls the odd gears (1, 3, 5, 7) and reverse. Clutch 2 controls the even gears (2, 4, 6).
The crankshaft transmits engine torque to the dual-mass flywheel which is then channelled through the clutch housing and onto the multi-plate clutches, or to be more precise, the outer disc carrier.
Under oil pressure, clutch 1 closes and forms a frictional connection with input shaft 1. The torque is now transmitted through the differential to the rear axle or, in the all-wheel drive variants of the 911, the front and rear axles.
At this stage, PDK has already preselected the next gear. Engine torque is already acting on the other outer disc carrier and, in response to a gear change signal, the overlap shift is initiated, i.e. as clutch 1 opens, clutch 2 closes. The non-positive connection with input shaft 2 is established, and power is transmitted to the wheels. The gear which is engaged is displayed on the instrument cluster.
PDK has distinct benefits. The very rapid gearshifts, with no interruption in the flow of power, produce faster acceleration.
Driving feels even sportier and more dynamic, and agility is increased. Depending on the gearshift program, the gear change is optimized for comfort or for sporty handling.
The compact dimensions of the gearbox reduce rotational masses, which results in a more direct engine response, and the system is more lightweight.
This, along with the long-ratioed 7th gear, helps to achieve reduced fuel consumption and emission figures comparable with those of a manual gearbox.
With the optional Sport Chrono Package Plus, PDK is enhanced by the ‘Launch Control’ and ‘motorsport-derived gearshift strategy’ functions.
This new, distinctively designed three-spoke sports steering wheel for PDK has two ergonomic paddles. One press with the thumb and the PDK shifts up.
One pull with the index finger and the PDK shifts down. Either the right or left hand can be used.
On request, the sports steering wheel for PDK is also available as a multifunction steering wheel (alternatively in smooth-finish leather, Aluminum Look, Carbon or Macassar). Steering wheel heating is available as an option in conjunction with PDK.
The gear selector for PDK is ergonomic and designed for high functionality, enabling you to change gear manually. The control concept mirrors the logic of the paddles on the sports steering wheel for PDK – press forwards to shift up, pull backwards to shift down.
Even if the gear selector is set to automatic mode, you can still change gear manually using the paddles on the steering wheel.
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