From the tires to the top, Porsche's all-new 911 Cabriolet bristles with technical superlatives.
When I drove the new 911 Carrera Coupe last summer, I raved about its overall blend of stunning performance and new found handling capabilities. When I drove it again at the Catalunya Race Circuit in the autumn, I was even more impressed with its handling at the limit. At that point, I thought that the car could not be measurably improved in any significant way. But I was wrong.
In the past, 91 Is have always had their structural integrity and therefore their handling, compromised by the removal of the roof. By designing the new Cabriolet as a model by itself from the ground up, Porsche have exorcised this devil once and for all. So the new 911 Cabriolet is able to offer the ultimate extra dimension of motoring pleasure to Porsche fans with next to no sacrifice in handling.
The other sacrifice was in rearward visibilty, because of the folded top and fiddly tonneau cover. That has been elegantly resolved by a Boxster-like top mechanism which takes the top below a smooth, flushfitting body panel.
The dynamic strengths of the 911 Carrera Coupe are its outstanding performance, handling and grip. The latter two qualities are enhanced by an extremely rigid bodyshell and a rear subframe which keeps suspension geometry true under high cornering forces. All these qualities are largely carried over to the 911 Cabriolet which is one of the fastest and structurally stiff open cars ever produced-this one 25 percent stiffer than its predecessor.
Your fingertips pick this up the moment you deviate from smooth interstates to badly maintained secondary roads. The superb absorption abilities of the Carrera's suspension system, even on the optional 7.5J and 10J x 18-inch wheels, takes the sting out of the bumps. But at the same time, despite superbly weighted powersteering and good road isolation compared to previous 911s, the massive 225/40ZRI8 and 265/35ZRI8 tires faithfully relay road surface information to the driver, but sans the level of kickback of older 91 Is that was known to worry drivers new to the marque.
The grip generated by such wide rubber usually serves to accentuate any structural weakness in a car's shell. The fact that one of the messages relayed through the helm of the new 911 Cabriolet on a bumpy road is that of a structurally stiff and resilient shell speaks volumes. Cowl shake was barely hinted at when pushing hard through the bends on bumpy Italian byways. It was exactly like driving a coupe that just happened to be roofless!
In the past, all Porsche 911 Cabriolets have been designed as conversions to the basic coupe structure. This time however, both were developed in parallel from the beginning as complete entities in themselves. This has made the new design visually coherent and so very much neater.
The fact that the Boxster and the new Carrera were also developed in tandem had a lot to do with this. Developing the Boxster, a roadster-only car, gave Porsche many valuable insights on the structure of what was to be their new Carrera Cabriolet. If one bears in mind the sharing of much of the internal structure of the two car lines, starting with the floorpan, then you can say that all three cars-the Boxster, 911 Coupe and Cabriolet- were developed as a family. This dramatically reduced development costs across the board to the benefit of the cars and customers.
Externally, the Cabriolet shares its sheet metal with the Coupe up to the ends of the doors. Aft of that, both the external and internal bodywork is new except for the engine lid and bumper. The new poweroperated top of the Carrera Cabriolet takes a page from the Boxster book, disappearing neatly under a metal rear deck cover in just 20 seconds with the touch of a button.
The car looks absolutely stunning from just about every angle (perhaps even better than the Coupe), preserving the Coupe's lines including two small rear side windows. Window frames tighten the top's fit along the windowline, without creases or wrinkles.
Porsche states that the electro-hydraulic operating mechanism is very similar with that of the Boxster, but there are also major differences. For one, the Carrera has a longer top to cover the cabin of the 2 + 2 seating arrangement. The locking mechanism has also progressed. Where you have to manually release and engage the locking mechanism at the top of the windshield frame on the Boxster, the Carrera Cabriolet's system does this automatically at the touch of a button.
In fact, sitting in the car and pressing the button with the ignition on but the engine off, is only one way of operating the top. However, should you be outside the car, you have the option of turning the key in the driver's door lock beyond the locked position or using the remote key control to raise or lower the top.
The canvas top itself is made from a very tough material Porsche calls "Sonnenland." The linkage and magnesium frame is concealed by an internal roof lining and the rear window is unfortunately, flexible plastic. It's a real pity that Porsche couldn't figure a way to use a glass rear window in both the Cabriolet and Boxster.
However, Porsche went to great lengths with their acoustic experts to achieve very low wind noise when the top is up. In practice, this work has paid off. The car feels really snug when the top is in place. Bombing down the autostrada at well over 130 mph, the loudest wind induced noise came from the external mirrors. And with the top up, the car has a very slippery 0.30 drag coefficient.
Stew Structure
Safety has always been an issue with cabriolets, and the new Porsche offers as much protection as possible to build into an open car. A bodyshell with exceptional torsional stiffness is a good start. It is also designed to deform in a very specific manner should the worst happen. Both driver and front-seat passenger get full-sized airbags and there are three-point inertiareel belts for all four occupants. Front side airbags are an option. Unlike the side protection airbags from other manufacturers, these have been specially designed for use in an open car.
The last line of defense is an extremely strong front windshield frame and two rollover bars which spring up from the deck area behind the rear seats when a tilt sensor detects a risk of overturning. They are cleverly hidden down in the rear seatbacks.
When winter comes and you want all the benefits of a coupe, you just refit the hardtop which comes standard with every 911 Cabriolet sold in the U.S. This double-layered and lined aluminium top weighs 65 lbs., has a heated glass rear window and a reinforcing aluminiurn rear parcel shelf. Fitting or removing it is a straightforward operation for two people and does not require a workshop which was the case before.
The power top was developed by Porsche AG and CTS (Car Top Systems), a company founded jointly by MercedesBenz and Porsche to develop and build the mechanisms for their convertible cars. The CTS factory in Korntal-Munchingen manufactures the tops and delivers the complete modules to Porsche ready for installation. They also designed and produce the hardtop.
Mechanically, the new Cabriolet is identical to the Coupe. The DOHC 3.4-liter water-cooled all-alloy flat-six has variable valve timing, a variable inlet manifold and produces 300 hp at 6800 rpm with 251 lb. ft. of torque at 4600 rpm.
At 3069 lbs., the Cabriolet weighs about 152 lbs. more than the Coupe, but it is still about 88 lbs. lighter than its predecessor. This extra weight has taken a slight edge off the Cabrio's acceleration compared to the Coupe. Zero to 60 mph takes 5.3 seconds, 0-100 mph, 11.9 seconds and top speed is 175 mph. The optional five-speed Tiptronic S version is of course, slightly slower.
Driving the car though, you would not notice the difference. The smooth engine has effortless performance in any of its six gears and is without doubt, one of the best engines in the business. Feed in the throttle at anything over 1000 rpm, and you get a linear increase in performance all the way to the redline. There is masses of torque everywhere in the rev band and you are never disappointed with the response to a demand for more speed. And even though the new water-cooled engine is quieter mechanically, it will still rip out that familiar hard-edged scream when revs climb above 5000 right on up to the 7500 rpm rev-limiter cut out.
Porsche expects at least a third of 911 sales to be Cabriolets but they can and will alter the production mix to suit demand. These figures are based on recent experience with the 993 Coupe and Cabriolet where overall production of Cabriolets ran at about a third. In fact, the model mix may vary from market to market, but it works out at a third of total production. The United States takes the largest number of Cabriolets, whereas markets like the Middle East and Far East prefer the Coupe.
The perception of the 911 also varies from market to market. In Europe for instance, the Coupe and Cabriolet are viewed as two different cars that appeal to different buyers. In the United States on the other hand, the two are looked upon as one car, and the launch of the Coupe has been held back to this May whereupon it will be launched simultaneously with the new Cabriolet. The new Carrera 4 will arrive later this year for both body types and a Targa will likely follow next year before the all-new Turbo. In any form, however, the new 911 is sure to be a hit. And as a Cabriolet, it will be hard to top.
The grip generated by such wide rubber usually serves to accentuate any structural weakness in a car's shell. The fact that one of the messages relayed through the helm of the new 911 Cabriolet on a bumpy road is that of a structurally stiff and resilient shell speaks volumes. Cowl shake was barely hinted at when pushing hard through the bends on bumpy Italian byways. It was exactly like driving a coupe that just happened to be roofless! 
The last line of defense is an extremely strong front windshield frame and two rollover bars which spring up from the deck area behind the rear seats when a tilt sensor detects a risk of overturning. They are cleverly hidden down in the rear seatbacks. 