Shifting gears: the history of PDK

Shifting gears: the history of PDK


Rainer Wüst laughs when asked about the beginning of this success story. He raises his hands almost in apology and says: “Well, the honor was great, the work was great. And then I, the boy. There was stress there too. But one thing is also clear: It was a great opportunity – and looking back, it’s a story very good.” Wüst had been a transmission test engineer at Porsche since 1971, and ten years later, at the age of 35, he suddenly took over as technical director, responsible for the development of the Porsche double clutch (PDK) electric transmission.

40 years ago, Rainer Wüst started a journey that has made travel easier for millions of drivers today.

That was more than 40 years ago, and Rainer Wüst shakes his head slightly at the moment when the defining innovation in automotive development became solid. “It was about combining the best of two worlds – the efficiency benefits of a manual transmission and the performance capabilities of a fully automatic transmission, which at that time still had many weaknesses. A big challenge for a small department like ours. Maybe it was ignorance that helped us – but certainly our pragmatism in addressing the challenge and our passion for the topic.”

Shipping expertise from Porsche

Porsche had already developed its own distribution expertise before. Porsche’s interactive development brought the distribution department forward. Wüst now had a strong professional team in his midst, which set about the task of creating a two-part transmission with great motivation. They were ready – but was the time right?

Rainer Wüst answers the question clearly today. But more on that later. 40 years ago, Wüst found the development of an old gearbox with the engineering expert Imre Szodfridt on the ground floor. In the late 1960s, he had already presented the idea of ​​a double clutch to Ferdinand Piëch, head of development at Porsche at the time. “Szodfridt was a smart guy, this preparatory work definitely helped us,” says Wüst. What didn’t help: In the early 1980s, there were no electronic power controls or mass-produced electronic valves suitable for cars. “We took the Szodfridt gearbox out of the basement and worked with pneumatic valves, which we operated with water. It was hard pioneering work from the ground up, but the result already had a pre-series status,” says Wüst.

944 Turbo, 2022, Porsche AG

Back to front. Jacky Ickx pioneered this development because the power of standing propels you forward anyway.

PDK display in the cockpit of the 944 Turbo, 2022, Porsche AG

Rarely seen: the PDK display in the cockpit of the 944 Turbo.

He is standing next to the 944 Turbo, in which the innovative transmission was successfully tested in the 1980s – a historic car with a PDK shifter on the central console: a minus sign in front of downshifts, and a plus sign behind for upshifts. That was enough for the switching process. It was an interesting development. Since the gear in PDK is divided into two small transmissions, each with its own clutch, of which only one is involved, the new gear can already participate in the second transmission. To change gears, only the new clutch used has to be closed and the previously used one opened at the same time.

944 Turbo with PDK, 2022, Porsche AG
A timeless beautiful tail – and transmission that was ahead of its time.

For Wüst and his team, however, the test in the Porsche 944 Turbo was only an intermediate step. Its head of development at the time, Helmuth Bott, was convinced that everything that could be tested in the race must also be tested there.

Rainer Wüst, 2022, Porsche AG

Rainer Wüst’s passion for development work 40 years ago can still be seen today.

So they decided to prove the performance of the new race-developed PDK with the 956. Drivers interested in racing technology immediately recognized the great potential of the new development. “We were able to shift gears and drive faster without interruption of traction,” recalls Hans-Joachim Stuck, who, according to Wüst, came up with the idea of ​​connecting the gear knobs to the steering wheel – the main idea of ​​which “Keep your hands on the steering wheel when shifting gears under full load It felt good to be able to do it from the start,” says Stuck.

Advantages of PDK

But with the advantage of no longer being able to reach the shift lever in the event of violent lateral acceleration on the curve and being able to be very fast at the end of the straight, for example, due to constant traction, PDK also provided other benefits. “Jacky Ickx learned early on to brake with his left foot in a corner and continue to accelerate with his right foot to keep the turbo going,” says Wüst. “So he had a lot of speed after the corner.” it was no longer possible, and the drivers were able to brake later before the corner because the PDK downshifted better.

“But there was still a problem,” adds Wüst. With each shift process, the PDK provided the racing car with a forward kick Shift gears allowing the car to move forward at all times. In a production car, this is an intolerable departure from comfort. zone, in motorsport a welcome increase in speed. “But these effects put a lot of stress on the gearbox and the whole shaft of the car. The increase in torque has few Sometimes it meant that everything blew up in our faces and I stayed at home. evening and left everything hanging,” recalls Wüst.

Then they reduced the weight of the gearbox and thus found their way. Stuck tested the new development in the 962, the first race car with PDK – and in 1986, together with Derek Bell, they achieved the first victory in the 360 ​​km race at Monza. In the end, both were able to win the 1986 World Cup.

962 C with PDK, 2022, Porsche AG
Guaranteed success in the 80s: Shell Dunlop Porsche 962 C with PDK.

PDK also attracted attention in the rally: Walter Röhrl immediately took first place when the Audi Sport-Quattro S1 with PDK was used for the first time at the Semperit Rally at the end of 1985. This is where the advantages of power shifting came into play due to the large number of activities conversion. However, success in the race did not lead to success in the series. In fact, the time was not yet ripe. “We were at least 20 years ahead of our time,” says Wüst. In addition to the development of valves and electronic equipment, which was not yet advanced enough for series production, the development of the use of the necessary wet clutch was also absent. .

Success of PDK

That only changed for the worse, when VW boss Ferdinand Piëch, to whom Wüst once reported in the early 1980s about PDK work (Wüst: “Piëch never forgot anything”), took over PDK and with the help of mature technology it has now made a success.

962 C with PDK, 2022, Porsche AG
The PDK mark on the Shell Dunlop Porsche 962 C: “There’s a piece of me there,” says Wüst.

Porsche introduced PDK in 2008 as an option for the 911 range. A year later, PDK found its way into the Panamera as a variant of the standard all-wheel drive architecture. It thus became the first Porsche in which PDK was fitted as standard in some derivatives.

It was a late success for Wüst, who by then had been promoted to head of chassis development. “PDK is definitely the highlight of my 38 years at Porsche. There were many great projects, this was one of the best,” says Wüst. Now he is standing next to the Shell Dunlop Porsche 962 C and is about to get a little emotional: “In your work you do a lot with a waste paper basket. But this one stays, I can grab it. That makes me proud. When I see a car with PDK on the road today, I know: there is a piece mine there. That’s a wonderful development.”

information

The text was first published in the magazine Porsche Klassik 23.

Author: Frieder Pfeiffer

Photographer: Heiko Simayer

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