The PDK Transmission

How Porsche’s quick-shifting PDK works.

January 15, 2015
The PDK Transmission 1
The PDK Transmission 2
The PDK Transmission 3

Throughout most of its history, Porsche has been synonymous with sports cars that involve the driver. The majority of these cars have been equipped with manual transmissions, and many hardcore Porsche enthusiasts would not have it any other way.

Porsche, however, has always been an engineering firm at heart that has continually worked to develop new technologies to enhance performance, driver comfort and safety. It was to this end that the Sportomatic transmission of the late 1960s was developed. This semi-automatic transmission concept was based on a conventional manual transmission, but it lacked a clutch pedal; the clutch was vacuum actuated via a microswitch that responded to movement of the gearshift lever.

The Sportomatic also featured a torque converter to allow the engine to idle without stalling while the vehicle was at rest. The “Sporto” was offered as an option in the 911 from 1968 and was initially well received, but consumer interest waned through the 1970s and it was eventually discontinued.

Porsche’s next attempt to expand its market share via the proffering of a two-pedal transmission option was much more successful. The Tiptronic transmission of 1990 was based on contemporary automatic transmission design, with planetary gearsets and a torque converter. Its innovation was electronic controls that allowed the driver to manually shift gears at will. This feature eventually became common in more conventional vehicles, but the more important implication of the Tiptronic was that its take rate greatly increased among buyers of Porsche sports cars throughout the 1990s and 2000s, especially in the American market.

The PDK

While the torque converter-equipped Tiptronic was vastly improved over the years, Porsche was well aware that it was no substitute for a proper manual gearbox in the view of performance-oriented drivers. The engineers at Zuffenhausen had been intermittently tinkering with the idea of a fast-shifting dual-clutch automated manual transmission since the 1970s in the form of the Porsche DoppelKupplung, or Porsche dual-clutch transmission.

Porsche’s main vessel of PDK development was the 956/962 endurance race car program of the 1980s. Despite its considerable weight penalty of 88 pounds (which is significant in a sub-2,000-pound race car), the original PDK transmission offered the promise of much quicker gearshifts and lap times. Porsche product planners also realized the PDK’s viability as the gearbox of the future in its road cars, so race development went full steam ahead.

Also from Issue 226

  • 991 Carrera GTS
  • Bangkok 911
  • Market Update: 1989-1998 911s
  • A 911 racer’s R Gruppe street car.
  • Porsche’s Sporting Scout Car
  • Grant Wolfkill
  • Profile: Peter Falk
  • Enzmann 506
  • The Keeper 924
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