2008 Porsche 911 Turbo Cabriolet First Drive

The 911 To Be Seen In

Published: 07/12/2007  - by Jason Kavanagh, Engineering Editor

Purists love to hate the Porsche 911 Turbo Cabriolet. Save for the Cayenne, few Porsches have drawn as much condescension from the cognoscenti.

Over its lifetime, the 911 Turbo has morphed from a hairy-chested badass to a refined GT car. And when the Stuttgart automaker last lopped off the top of the 911 Turbo in 2003, the spirit of the first Turbo Cabriolet was resurrected, a symbol of wretched 1980s excess. Porschephiles everywhere groaned.

Now the 2008 Porsche 911 Turbo Cabriolet is with us, a car based on the new 997 platform of the 911. Personally, we can think of worse things than an all-wheel-drive 911 Turbo with a top that disappears. Are the purists wrong, or are we lost in some kind of time warp where Miami Vice is a logical lifestyle choice?

The Consequences of Going Without Your Top
Once you cut the roof from any car, you can bank on a few side effects: vastly diminished structural stiffness, more weight in the process of compensating for same, reduced aerodynamic slipperiness and more wind noise. In creating the $136,500 Turbo Cabriolet, the most expensive variant of the 911, Porsche has nevertheless done an admirable job of managing most of these adverse effects, as we learned when we drove the car in the countryside near Frankfurt, Germany.

The Turbo Cabriolet is largely similar to the Turbo coupe, only additional metal has been bonded and welded to the rocker sills and floor pan to help restore some of the structural rigidity lost with the removal of the roof. This work to the body shell adds weight, of course, yet once you factor in the additional structure plus 93 pounds more for the electrical folding top and rollover-protection hoop, the 2008 Porsche 911 Turbo Cabriolet comes to the curb at 3,649 pounds, only 154 pounds more than the Turbo coupe.

The Cabriolet also has a surprising amount of structural rigidity. At 6,638 pound-feet/degree, the Cabriolet is 738 lb-ft/degree (13 percent) stiffer in torsion than the previous 996-based Turbo Cabrio. Nevertheless, the Cabriolet has just one-third the torsional stiffness of the 911 Turbo coupe; a measure of the importance of a roof to an automobile's structural integrity. In the Cabriolet, this loss of rigidity manifests itself as tiny quivers you can sometimes feel in your backside while driving over uneven pavement.

New Lid, Familiar Silhouette
Cabriolet-specific revisions to the springs, dampers and antiroll bars of the 911 Turbo's suspension were necessary to maintain ride quality, which proves compliant enough for daily driving. If you choose the optional Porsche Ceramic Composite Brakes, the ride quality might further improve from the reduction in unsprung mass. These brakes also help reduce the sprung mass of your wallet by relieving it of an eye-watering $8,840.

With the top up, the Cabriolet convincingly retains the smooth, humpbacked roof line of the 911. Elegant it isn't, however. The additional cut lines in the Cabriolet's bodywork add to the visual clutter of the Turbo coupe, which includes vents, slots and zoomy 19-inch wheels. The overall look is slabby rather than svelte.

The wind doesn't notice. The rear wing extends 1.2 inches further than the coupe's movable element to help the Cabriolet maintain the same aerodynamic lift characteristics (and 0.31 drag coefficient) as its tin-topped counterpart.

20 Seconds to Freedom
Pressing a single button tucks the Z-fold soft roof cleanly into the rear deck in about 20 seconds, an action that can be done at speeds up to 31 mph. It's worth the short wait — when the top is down, wind noise is minimal and buffeting within the cabin is largely nonexistent even at autobahn speeds.

Much of the credit goes to a windblocker panel that mounts above the cargo — er, seating — area behind the front seats. When not in use the panel folds up and is stored in the trunk. A 73-pound aluminum hardtop is available as an option for those seeking security.

Sit down. Look around. If the Cabrio's interior looks familiar, that's because it is another carryover from the coupe. Except for the fabulously extravagant three-layer folding headliner, of course.

Shared Motivation
You already know all about the Cabrio's twin-turbocharged 480-hp, 3.6-liter power plant, since it's unchanged from the coupe. Headlines include variable-geometry turbo whiz-bangery, which generates quicker boost response by varying the velocity of the exhaust gas reaching the turbines.

The result? Torque production responds to the position of your right foot with commendable linearity. Mat the throttle and there's only the tiniest pause before the Turbo's formidable reservoir of torque is channeled forth through all four wheels, hurling the car forward effortlessly. The Turbo engine might not have the urgent yowl of the 911 GT3's normally aspirated engine, but there's still the unmistakable flat-6 wail and an intake whoosh that the alfresco Cabrio makes even more noticeable.

As expected, this thing is deceptively rapid. There's 457 lb-ft of torque delivered between 1,950 and 5,000 rpm in a curve that's as flat as week-old hefeweizen. It might have put on a few pounds, but the Cabriolet nips at the heels of the Turbo coupe when it comes to speed.

Porsche claims the Cabrio will cross the line at 100 kph (62 mph) in 4.0 seconds and reach 124 mph in 12.8 seconds with the row-it-yourself six-speed manual transmission. The optional $3,420 five-speed Tiptronic S autobox betters these numbers by two-tenths since it allows you to brake-torque the car at the starting line to build turbo boost for a quicker launch.

It's hard to imagine any Cabriolet owner doing such a thing, however. Between the folding roof and more willowy chassis, the Cabriolet works best as a relaxed high-speed cruiser. There are other Porsche 911 models in which to play racer.

As in the 911 Turbo coupe, the Turbo Cabriolet offers more urge if you want it. The optional $1,920 Sport Chrono Package provides a 10-second overboost function to lift torque to 501 lb-ft between 2,100 and 4,000 rpm. Normal boost pressure of 14.5 psi is raised to 17.4 psi during this overboost period, and we're told that the transmission's ability to shed heat dictates the limit of 10 seconds.

A Different Kind of Speed
There's no question that the 997-based 2008 Porsche 911 Turbo Cabriolet is fast and utterly capable, and the corporate strategy of broadening the marque's appeal with such models has indisputably been good to Porsche's balance sheet.

Just the same, this is not a simple, flyweight 911 with more motor and less roof. It's a GT car, more like a Jaguar XKR convertible than a Ferrari F430 Spider. That's why we strongly believe the leaner, meaner 911 GT3 embodies Porsche's core values better than any other model in its lineup, including the almighty 911 Turbo.

Well, the purists might be right. This is a car that's more about style and speed, and not so much about Porsche-ness. Still, as crushingly fast cruisers go, there are few better than the 2008 Porsche 911 Turbo Cabriolet. Maybe it's all right to give in to your inner Sonny Crockett once in awhile.

Edmunds attended a manufacturer-sponsored event, to which selected members of the press were invited, to facilitate this report.