2009 Porsche 911

Consider the 2009 911 a brand-new car, even though the basic structure remains essentially the same as the outgoing model's. Two entirely new and more powerful engines and a new twin-clutch automatic transmission are the major refinements to Porsche's 45-year-old model, but there's much more to the transformation than the powertrains.

Suspension, brakes, lighting, interior and exterior styling all were massaged for the Carrera and Carrera S, and the process has resulted in the best 911 yet. We drove both models on a drizzly day over autobahn and narrow German back roads, and all we could do at the end of the drive was shake our heads in admiration: They've done it again. They've built a better 911.

Arriving at North American showrooms in September, the lineup is a base Carrera Coupe, outfitted with a 3.6L, 345-hp boxer six and mated to a revised six-speed manual, at $75,600. The base Cabriolet and Carrera S Coupe, which is powered by a 3.8L six with 385 hp, are both $86,200, while the Carrera S Cabriolet is $96,800.

Both models boast more power, bigger brakes, more athletic suspensions, and a clean and classic exterior rehabilitation, but arguably the most significant aspect of the oh-niners is Porsche-Doppelkupplungsgetriebe (say PDK to avoid lingual strain), the new twin-clutch gearbox that replaces the generally unloved Tiptronic S.

Built by ZF, PDK has a three-shaft configuration that's more compact than Tiptronic, lighter by 22 lb, and so slick in operation there's no auxiliary cooler even though less gearbox oil is used to reduce internal drag. Airflow is all that's required to keep the oil at optimum temperature, though a separate oil chamber, cooled by a small heat exchanger, is used to lubricate the two wet clutches that give the gearbox its name. One clutch handles the odd gears, 1-3-5-7, and the second engages 2-4-6. PDK offers a range of shift strategies within its software, from a total consumption-optimized approach to one that gets the most out of the powertrain, but either way the gears change more quickly, by up to 60 percent when the car is fitted with optional Sport Chrono Plus.

When asked to lope along, PDK reaches the taller gears in less time and culminates in an especially economical seventh gear. When the driver goes to the whip, acceleration is optimized by exploiting the rotary mass's energy during upshifts and by eliminating the interruption of tractive force. In the sport modes, downshifts are accompanied by a rev-matching blip of the throttle, and kick-down will drop top to second gear without visiting any of the intervening ratios, and without any noticeable passage of time.

Especially welcome are the steering-wheel mounted switch-like paddles -- push to change up, pull to shift down -- that replace Tiptronic's cheesy plastic buttons. They're fixed just above the new three-spoke steering wheel's two lateral arms, which makes it easy to keep track of their placement when cranking through corners. As before, automatic or manual modes are chosen by repositioning the console-mounted shift lever, which also offers push/pull gear selection.