S erendipity, they call this. It is the hottest day of the year in Britain, the 911’s on-board thermometer showing a scorching 34.5o C, and your favourite automotive magazine team are out on road test with a delectable double of 991.2 Carrera Cabriolets. Basking in the sun’s intense glare, both 911s are topless, their fourpanel roofs stowed neatly under the curvatures of their respective posterior. I can’t help but feel lucky to call this ‘work’. Aside from the favourable bright sunshine beating down on Josh, my Features Editor, and I, our 991.2 Carreras are delivering the full accoutrement of the 911’s traditional Cabriolet experience, namely a positively visceral auditory of the hard-working internal combustion engines behind us.
In 991.2 guise this means that, as an overtone to the snarling and popping of exhausts as each car rides in Sport mode, there’s a high-pitched whooshing from the turbochargers as Josh and I traverse a narrow corniche along the breathtaking Elan Valley’s southern front. Situated in the very centre of Wales, the road dissecting the Elan Valley has long been a Total 911 favourite for its brisk changes in elevation, pace and accompanying scenery. Save for the obligatory sheep inevitably loitering close by (perhaps tyre detritus and surplus tarmac chippings are the perfect garnish to the habitual Welsh terrain?), the road is wonderfully quiet, giving us plenty of time and space in which to exploit the boundaries of our impressive Porsche 911 Carrera Cabriolets.
This is just as well, as the fact both cars are Cabriolets is of little relevance to today’s journalistic test. The reason we’re here, then, is because the Carmine red 991 I find myself in has drive going to all four wheels, while the Graphite blue example Josh is piloting employs the conventional 911 genetics of rear-wheel drive. In years gone by, a C2 v C4 head to head would be a largely superfluous exercise. The rear-driven car has always been a purist-pleaser, is faster, and doesn’t understeer so readily, while the C4 is intended for those whose 911 brief is unabated everyday usability. Now though, the terrain is different. The 991 generation’s 100mm extended wheelbase and revised engine position, now sitting more atop that rear axle, has blessed the entire model line-up with a deftly balanced chassis. As a result, understeer has been greatly reduced, the C2 and C4 included. Then, when the Carrera went turbocharged for the 991’s second generation, something quite incredible happened: for the first time, the all-wheel-drive variant boasted a quicker 0-62mph sprint time over its rear-driven comrade. This means that in terms of true, outright performance, the new C4S is now the de-facto choice for those wanting the fastest possible Carrera.
So where does this leave the rear-wheel drive variant? Well, the difference in sprint time from 0-62mph between the C2 and C4 is just 0.1 seconds, hardly a night-and-day conclusion to proceedings. Besides, at Total 911 we don’t decide duels by statistics, we decide them by feel, deliverance and above all, emotion. The Carrera 2 may have its tail between its legs when it comes to a dash off the line, but overall the RWD and AWD cars are closer than ever before. So which edges it? The Carmine red Carrera 4S was busy winning me over even before I took a seat in it. Entirely subjective I know, but the four-wheel-drive Carreras are visually superior to the Carrera 2s. Their wider body gives a more aggressive stance on the road (admittedly, I think this works better in Cabriolet form with the roof stowed) while there’s an undeniable beauty to that red connecting light between those rear clusters, something the rather more simple Carrera 2 doesn’t have.
These extra aesthetic devices are a clue as to the additional engineering that’s gone into the all-wheeldrive 911. For while its rear axle is always driven (and biased), the C4 employs an active all-wheel-drive system using an electro-hydraulic multi-plate clutch with variable map control (PTM) to send power to the front wheels, too. Honed on the first-generation 991, the new Porsche Traction Management system is taken direct from the Turbo and is more sensitive than the previous model, responding quicker than it, too. Tied in with Porsche Stability Management and a host of sensors monitoring the rotational speed of each wheel, steering angle input and longitudinal and lateral acceleration, Porsche says its PTM takes no longer than 100 milliseconds to react at any one time. Blink and you will have missed it, quite literally. To add to the traction armoury, 4S examples such as this get a limited-slip differential with Porsche Torque Vectoring, which brakes the inside rear wheel (on manual gearbox cars the diff is mechanically locking but for PDK it’s electronically controlled with PTV Plus, which is essentially more active).