KEY POINTS:
Porsche has always taken an evolutionary rather than revolutionary approach to its legendary rear-engined 911 - and the latest facelift is no different.
But you will have to look closely to spot changes to the new Carrera and Carrera S when the cars land here around September.
Both
models get a new-look front bumper and grille, and the revised headlights, indicators and tail lights get LED bulbs.
But the big news is under the skin. For the first time ever, the German company is offering a rapid-shifting dual clutch gearbox as an option.
Called PDK (Porsche Doppler Kupplings), the seven-speed unit is a development of a system first used 25 years ago in the company's Le Mans racers. Audi also had something similar on its rally cars back then.
Using either the gear lever or paddles mounted on the redesigned steering wheel, drivers can now change ratios around 60 per cent faster than with the old Tiptronic semi-automatic set-up, says the company. PDK also weighs 10kg less than Tiptronic.
To make the most of the new transmission, engineers have upped the power on the car's trademark flat-six motor while reducing the weight of the engines by 6kg.
A range of tweaks, including the addition of direct injection (standard on the Cayenne V6 and V8 engines since last year) mean the output from the Carrera's 3.6-litre engine increases by 15kW to 258kW, while the 3.8-litre S is boosted by 22kW to 288kW. Performance is blistering, with the Carrera and higher-powered S sprinting from zero to 100km/h in 4.7 and 4.5 seconds respectively.
The revisions also mean fuel consumption is reduced by about 12 per cent across the range, giving a claimed town and around consumption of 9.6 litres/100km, or 29.4mpg.
Porsche says CO2 emissions are down by up to 15 per cent to 225gr/km to meet EU5 emissions regulations.
The coupe and the convertible versions of the Carrera models benefit from the upgrades, while the faster Turbo, GT3 and GT2 remain unchanged.
In principle, PDK, like the Volkswagen Group's Double Shift Gearbox (DSG), consists of a conventional manual gearbox and a hydraulic control system divided into two separate transmission units.
Two wet clutches in radial arrangement, controlled hydraulically, and using oil for both cooling and lubrication, form the heart of the transmission. One clutch handles the uneven gear ratios (1,3,5,7) and reverse, and the other the even gears (2,4,6).
Via a number of pressure valves, the hydraulic control unit masterminds the wet clutches and the shift cylinders to activate the transmission ratio required.
The big advantage is an even faster gearshift than with a conventional manual gearbox or torque converter automatic transmission.
It's pretty much a simultaneous process - the clutch on one transmission opens or disengages while the clutch on the other transmission closes or engages. The gears are already in mesh when shifting and the power of the engine need not be interrupted in the process.
Porsche says PDK contributes mightily to the 12 per cent fuel saving.
