Click above for high-res gallery of the 2009 Porsche 911 Carrera S with PDK

Click above to watch Porsche's PDK gear box in action

Porsche's unveiling of the 2009 911 Carrera also came with the introduction of the new PDK seven-speed twin-clutch gearbox. It can shift 60-percent faster than the Tiptronic system, and reportedly helps the 911 S lap the Nurburgring eight seconds faster than the six-speed variant. Porsche has released a video explaining more about how the PDK works, showing off the dual wet clutches that are simultaneously connected to two gears so that when gear is engaged the next gear has been selected, essentially providing instantaneous shifts. Follow the jump to watch the PDK gear box in action and learn more about how the dual clutch system works.

Porsche, like every other automaker under the sun, is under pressure to produce vehicles with improved fuel efficiency that emits less CO2. The current 911 puts out 225 g/km of CO2, but Porsche believes that it can hack another 10 g/km off that figure with the implementation of start-stop technology on its flat-six engines. Not so fast, say Porschephiles. According to the automaker, buyers aren't fond of such a feature on their arse-engined performance machines. Porsche didn't cite the reasons behind consumer's reluctance, but a 10 g/km reduction doesn't seem like much in the overall product scheme of Porsche.

Click above for a high-res gallery of the 2009 Porsche 997 Carreras