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.

During the launch of the 2009 911, CAR asked Porsche engineers what the CO2 limitations are of the current flat-six, and according to Thomas Wasserback, "it might be possible to produce a Boxster that emits 180 g/km, it would be difficult to engineer a 911 to produce 200." However, Porsche intents to maintain current performance levels, despite a possible reduction in engine output, by lessening equipment levels and making use of more lightweight materials and body shells. Interestingly, Porsche estimates that the new 911s equipped with the seven-speed PDK transmission, which increases fuel economy and decreases emissions, will account for 80-percent of all 2009 911s sold and could spell the end of the stick shift within five years. However, manual transmissions will remain standard on Porsche's 911 Turbo, GT2 and RS models due to the torque limitations of the PDK gearbox, but a stronger version of the 'box is in development, so expect to see dual-clutch technology on all those models in the coming years.

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[Source: CAR]