Porsche Doppelkupplungsgetriebe (PDK)
The new generation Porsche 911 Targa 4 and 4S are available for the first time with the new Porsche Doppelkupplungsgetriebe (PDK), literally Porsche double-clutch gearbox. Offering no less than seven forward gears, the new gearbox combines the driving comfort of a torque converter-equipped automatic transmission with the dynamic manual gearshift functionality of a sequential racing gearbox. PDK also boasts an entirely automatic gearshift function, and replaces the Porsche Tiptronic S automatic transmission offered previously. Through its optimised and adaptive gearshift programmes, PDK further improves the acceleration of the 911 and reduces fuel consumption to an even lower level.
In principle, 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 both cooling and lubrication, form the heart of the transmission. 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 masterminds both the wet clutches and the shift cylinders activating the transmission ratio required.
The gearshift perceived by the driver comes not from the gears actually changing, but from the change of positive clutch engagement. In this case, the clutch on one transmission opens or disengages while the clutch on the other transmission closes or engages in a simultaneous process. The big advantage is an even faster gearshift than with a conventional manual gearbox or torque converter automatic transmission. The gears are already ‘in mesh’ when shifting and the power of the engine need not be interrupted in the process.
PDK also reduces to a minimum transmission power loss courtesy of the high standard of mechanical efficiency in the double-clutch, and this manifests itself in fuel economy improvements of approximately 13 per cent compared with a conventional Tiptronic S transmission. PDK also offers an advantage in terms of weight – despite two additional gears, it weighs 10kg less than Tiptronic S.
To use the various functions of the double-clutch transmission, the driver can either shift gears by means of sliding toggles on the spokes of the new steering wheel, or via the new gear selector lever. The driver can press forwards to shift the gears up, and press them from behind to shift downwards. Alternatively, pushing the gear selector lever forwards shifts up a gear, and pulling it back shifts down. The option of PDK costs £2,338.
This PDK gearshift principle was first developed by Porsche for motor sport 25 years ago. Porsche works drivers benefiting from this technology were able to accelerate faster than their competitors and keep both hands on the steering wheel while changing gears, thus avoiding even the slightest distraction while shifting.
The seven-speed PDK shifts gears up to 60 per cent faster than a conventional automatic transmission, and naturally, gives the new 911 Targa models even better performance.
For example, with the manual six-speed gearbox, the 911 Targa 4 accelerates to 62mph (100km/h) in 5.2 secs and the even more powerful S-model completes the same exercise in 4.9 secs. The optional Porsche Doppelkupplungsgetriebe shifts gears even faster to set an even higher standard, the 3.6-litre Targa 4 with PDK accelerating to 62mph in exactly 5.0 secs, the Targa 4S offering an even faster and more dynamic 4.7 secs.
And those in search of optimum driving dynamics have the option to combine PDK with Sport Chrono Package Plus, now featuring Launch Control.
As with the second generation 911 models series overall, these latest 911 Targa models are distinguished by the discreet modification of the nose and tail and the use of new lighting technology. All 911 Carrera models feature, as standard, bi-xenon headlights and new LED daytime driving lights. Dynamic Cornering Lights are available as an option.
Like the 911 Carrera 4 and 4S models, the Targa 4 and 4S is 44mm, or 1.73”, wider across the rear wheel arches than the two-wheel drive 911. Further definition and character is added courtesy of a new reflective trim that spans the width between the LED rear lights.
Porsche Communication Management (PCM)
Inside the 911, the new Porsche Communication Management (PCM) centre console with its larger, touch-sensitive screen improves operation of the audio system and optional satellite navigation to an even higher standard. And a further important point is that PCM is now compatible with Bluetooth, USB and iPod requirements.
Porsche 911 Targa 4 Prices
The second generation Porsche 911 Targa 4 models go on sale in Great Britain and Ireland on 25th October 2008. The Targa 4 Coupe 3.6-litre is priced from £72,980, and the Targa 4S Coupe 3.8-litre is priced from £80,270.
Fitted to every 911 is a Porsche Vehicle Tracking System (VTS), a sophisticated vehicle security package approved to Thatcham Category 5 standard, and customers will also be able to explore the potential of their new car on a Porsche Driving Experience course.Published 28 July 2008