Porsche 911 Turbo Cabriolet 2008

The 911 Turbo Cabriolet is Porsche’s lucky fourteenth version of the 997 model and only the GT2 and Turbo S models remain to be built. We took some time in the version with the six-speed manual, but most of our driving was with the five-speed Tiptronic S. Though only 20 percent of North American 911 customers opt for the Tiptronic S sequential automatic (while the rest of the world ranges between 40 and 60 percent), in the Turbo Cabriolet we prefer it. The 997 Turbos with Tiptronic S go quicker from 0-60 miles per hour, while, on the other hand, the cabriolet lifestyle should be lived with as little effort as possible, hands always free for other things.

Car Top Systems supplies the roof mechanism for all 911 cabs. The automatic system works as well as we remember, requiring just sixteen seconds by our count (Porsche claims twenty seconds) to either open or close. You can also open or close the roof while traveling at any speed up to 31 mph—only a semi-benefit, as a Porsche Turbo should never be traveling so slowly. Curb weight for this cabrio Turbo is reportedly only 154 pounds greater than that for the coupe. At 3726 pounds in Tiptronic S trim, therefore, that means each of the 473 horses in the 3.6-liter twin-turbo engine is responsible for lugging around just 7.9 pounds. (And 7.7 pounds per with the six-speed manual.)

Much of the added briskness in this generation Turbo is due to the variable turbine geometry turbochargers that were created to consistently handle the intense heat under hard throttle while practically eliminating turbo lag. Under total throttle with Porsche Active Suspension Management in sport mode and with Porsche Stability Management off—and with the 45 added pound-feet of torque overboost between 2100 and 4000 rpm via the Sport Chrono package—the Turbo on dry, warm pavement literally hunkers down flat like a lioness on the prowl. The sound of the exhaust under full 502-pound-foot pressure is not so much rumble or roar, but like a high-pressure sand-blaster with some thunder in the belly. The all-wheel-drive system discreetly sends up to 40 percent of this torque to the front axle (normally just 5 percent), creating a feeling of utter stick-to-itiveness through the seat of the pants.

In many a roofless sports car, aerodynamics can go all to hell. The coefficient of drag usually spikes much higher than in the hardtop version, frequently to the detriment of the car’s driving dynamics. Porsche is bored with this reality and has managed to keep the drag coefficient for the cabriolet with roof up the same as for the coupe, at 0.31. This was done by allowing the rear wing on the cabrio to extend 2.6 inches, 1.2 inches farther than the coupe. According to Porsche officials, this makes the 997 Turbo Cabriolet the only sporting droptop on the world market to create active rear-axle down force in order to maintain the stability of the coupe. We definitely feel the improvement over other 997 cabriolets, as well as a notably better drive versus the 996 Turbo Cabriolet. At the 193-mph v-max, the car is unflappable. Without a solid roof, the Turbo’s torsional rigidity is naturally compromised, but body wag is hardly noticeable thanks to the 911’s traditionally short wheelbase and narrow tracks.

One bit that is always up for improvement on the 911 design is the resultant high wind noise, particularly from the two rear corners of the roof. Roof shut on the cabrio, this noise while traveling at any speed greater than 75 mph becomes rather huge. With the roof open, therefore, thank goodness for the really effective wind-buffeting screen behind the headrest. We had all side windows up and this screen in place for our roof-down faster sections and felt a negligible amount of wind-swirl in the cabin—despite the monumental white noise. We tried a stretch at speed with the windows down and screen retracted, and you don’t wanna know about the eye surgery our long-locked driving partner required afterward.

But with sun and fun at this level, and with the realistically limited clientele, who actually whines that much about the good old-fashioned turbocharged wind factor? Porsche in Germany tells us deliveries in North America are slated to start September 8. Pricing starts at $136,500 if you choose the six-speed manual—a $13,600 premium over the coupe.


Jacobi S said...

Yeah, wind noise and buffeting are the two dreaded gnomes that spoil all the fun of alfresco rides. Mounting a wind deflector is an absolute necessity to tackle these gremlins in roadsters. Well on my Cabrio, I have mounted a Backblade windblocker and it’s doing a great job of keeping my cabin noise-free and tranquil.