When Porsche first introduced the 7-Speed Porsche Doppelkupplung (PDK) in 2009, the industry viewed it as a game changer. The modern PDK program can be traced back to the 956 and 962 sports cars of the 1980s, but it really came of age in 2009. The quick-shifting original 7-Speed PDK, which debuted in the 997, shared much of its architecture with the contemporary 7-Speed manual. This new 8-speed PDK transmission, developed for the Panamera, combines the original system's extremely fast shifts with improved packaging, a higher torque ceiling and an additional gear for the next generation of cars and fuel efficiency.
The latest Panamera is not grossly larger than its predecessor, and the models are more powerful across the range. The increasing importance of hybrid models means that this new PDK transmission needs to integrate more technology than ever before. The massive torque of the Panamera hybrid models has to be accounted for, alongside improving efficiency in conventionally powered Porsche vehicles, while providing a driving experience befitting of a Porsche.
Oh, and it can't be any larger than the old 7-Speed PDK.
Packaging for Performance
At first glance, the new 8-Speed PDK looks quite similar to the preceding 7-Speed PDK used in the Panamera. Like its predecessor, the new transmission uses two countershafts linked to a single mainshaft. The fixed gears on the mainshaft are designed to be shared between various ratios on the countershafts, allowing the transmission to decrease in size overall. The transmission is designed with higher internal gear speeds to decrease power loss.
A New Modular Concept
In addition to being compact, the new PDK transmission is extremely strong. The torque ceiling is up to some 737 ft-lbs, and the modular concept allows the same basic transmission to be used in both hybrid and non-hybrid models (the original Panamera hybrid was the only model in the range with a Tiptronic transmission). The hybrid module is integrated directly into the dual-clutch bellhousing. All of the key components, including a torsional damper, the electric motor and separating clutch and hardware, can then be packaged in a very small space on the input side of the transmission. The positioning of the hybrid components allows the 100kW electric motor to accelerate the Panamera to 87MPH on electric power alone. The new PDK transmission affords three overdrive ratios for the sake of efficiency, and the Panamera reaches its top speed in sixth gear.
The modular concept continues to the various supported drive trains. The new PDK transmission works with both hybrid and non-hybrid models, as well as both rear and all-wheel drive models. In all-wheel drive applications the front wheels are driven by a hang-on clutch. For the time being this new transmission is exclusive to the Panamera; the Cayenne will continue with the Aisin 8-Speed Tiptronic transmission in the interest of preserving its off-road and towing capabilities.
The new Panamera hybrid models offer better fuel economy than many economy cars, and better performance than many sports cars. As remarkable as the engines and motors are on their own, their power is nothing without the ability to put it to the road. In conjunction with the exciting new powertrains, the new 8-Speed PDK makes the Panamera both faster and more efficient than ever before.