Dual-clutch gearboxes – from the Porsche 956 to the Kia Ceed
There was a time when a fast car had either a manual gearbox or an optional, and usually terrible, automatic. Take the original Honda NSX, for example, which came with a five-speed and later a six-speed manual, and a truly, truly awful four-speed automatic as the alternative. Those days are mostly had long gone, and lower down the automotive food chain conventional automatics are becoming less and less common too – usurped by the double-clutch automatic.
To simplify things vastly, where an old school torque converter automatic uses fluid to transmit the power and torque of the engine to the driven wheels, a double-clutch automatic is a type of automated manual ‘box in which, as the name suggests, there are two clutches, allowing you to drive in one gear with the next gear ready to rumble. The trade-off is often low-speed smoothness – which torque converters have in spades – for shift speed, something double-clutch boxes are renowned for.
The concept of a dual-clutch gearbox dates back to the late 1930s and an engineer called Adolphe Kégresse. It was to be used in the Citroën Traction Avant, but, sadly, Kégresse’s money dried up and the double-clutch wasn’t seen again until the Hillman Minx of the 1960s. That’s right, the Hillman Minx. But Hillman can’t be credited for the now widespread use of dual-clutch gearboxes, but Porsche. Porsche first used a dual-clutch gearbox in the 1980s, dropping a ‘Porsche Doppelkupplungsgetriebe’ or PDK ‘box into a Porsche 956 in 1984. Just two years later a Porsche 962 C won the Monza 360km race with a PDK gearbox.
Fast forward nearly two decades and it was the Volkswagen Golf R32 that became the first road car to use a double-clutch, and since then it has sprung up in supercars like the Ferrari 458 Italia, Porsche 911 GT3 RS, and Bugatti Veyron. At the other end of the scale you can find a double-clutch in a Volkswagen Polo, Kia Ceed and Ford Fiesta, as well as the Volkswagen Golf, and with six, seven, eight, nine and even ten speeds.