One of the highlights of the Detroit motor show this month is the new Cabrio version of the Porsche 911 Carrera. Due here 'in about March', according to local dealer Porsche Centre Hong Kong, the model arrives with a new hood that retains the model's classic roofline and uses magnesium in its components to reduce weight and fuel consumption, and improve ride comfort, the German marque says.
Built with a longer wheelbase and a wider front track than its predecessors, the new Porsche 911 Carrera convertibles are fitted with the marque's latest electro-mechanical power steering and, along with other optional active control systems, the promise of a more precise and agile drive.
The new models are fitted with the same engines as the 911 Coupe equivalents, the 350-horsepower 3.4-litre Carrera Cabrio and a 400hp, 3.8-litre Carrera S version, both with the option of a seven-speed manual or Porsche double-clutch (PDK) transmissions that offer more fuel efficiency and faster acceleration. Both models consume less than 10 litres of fuel per 100km on combine runs. Porsche says.
The seven-gear PDK transmission is automatic and has proven as popular as the marque's Tiptronic S system.
Popular among Hong Kong's Porsche community, the PDK 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 cooling and lubrication, form the heart of the transmission,' Porsche says.
'One clutch is for the first transmission unit with the uneven gear ratios (1,3,5,7) and reverse, and the other clutch is for the second transmission unit with the even gears [2,4,6].'
Via a number of pressure valves, the hydraulic control unit manages the wet clutches and the shift cylinders to activate the transmission.
The gearshift occurs when the clutch on one transmission opens or disengages, while the clutch on the other transmission closes or engages in a simultaneous process, Porsche says.
'The big advantage is an even faster gearshift than with a conventional manual gearbox or torque converter automatic transmission,' it says. 'The gears are already 'in mesh' when shifting and the power of the engine need not be interrupted in the process.'Topics: Sports Cars Mechanical Engineering Road Transport Porsche Road Transport Automatic Transmission Automatic Transmission