In Porsche’s decades-long history, few developments have proven as crucial to the brand’s continued success as the Porsche dual-clutch transmission (AKA “Porsche-Doppelkupplungsgetriebe” or simply PDK).
In short, the PDK is similar to a manual transmission, but with two electronically controlled clutches that work together, one handling even gears and the other odd, to pre-engage the next gear while the previous is in use, resulting in super-fast changes and the option to shift manually or automatically.
But how did such an innovative piece of engineering come to be?
It was back in the 1980s when a young transmission test engineer named Rainer Wüst dredged up prototypes of a dual-clutch system that had been originally floated by famed engineer Imre Szodfridt in the 1960 and sat in storage since.
“Szodfridt was a very clever man, so this preliminary work helped us,” Wüst recalls, explaining how he, then the Technical Manager for the project, and his team worked to upgrade the tech in a time before control electronics or electrohydraulic valves were available to automakers. “We got the Szodfridt transmission from storage and worked with pneumatic valves, which we converted to work hydraulically. It was complicated pioneering work from the ground up, but the result already had pre-series status.”
The first working unit was set into a 1980s 944 Turbo, which wore the PDK gear lever in the centre console along with instructions to push the lever to shift down and pull to shift up. It worked.
“The idea was to combine the best of two worlds – the advantages in the degree of efficiency of a manual transmission and the potential for performance of full automation, which still had many weaknesses at the time,” says Wüst. “It was a huge challenge for a small department such as ours. Maybe it was naivety that helped us, but certainly our pragmatism in dealing with the challenges did – as well as our passion for this subject.”
With the first use-case a success, Porsche decided to test the tech further on the track, this time in a 956. It was here that the brand’s professional drivers noted the performance benefits of the smoother, faster gearbox.
“We were able to change gears and drive significantly faster without interrupting the engine’s drive,” remembers Hans-Joachim Stuck, who Wüst says was the first to suggest placing gearshifters on the steering wheel. “Being able to keep my hands on the steering wheel when changing gears at full throttle felt great right from the start.”
The PDK’s advantages became more apparent with each lap. Drivers no longer had to reach down to shift gears during sharp corners. They could brake later into corners as the PDK shifted down easily for them. Power was served up in an uninterrupted fashion, allowing for a higher top speed. Iconic Porsche driver Jacky Ickx even developed a trick of his own to give him a boost coming out of corners. “Jacky Ickx quickly learned to brake with his left foot when cornering and accelerate with his right to keep the turbo going,” Wüst recalls. “This made him significantly faster coming out of a corner.”
In 1986, Derek Bell drove a Porsche 962 using a PDK to an historic victory at the 360-kilometre race at Monza, and then followed it up with a win at the 1986 World Sports-Prototype Championship. This was just months after an Audi Sport-Quattro S1 with PDK took the top spot at the 1985 Semperit-Rallye.
But, due to the aforementioned lack of commercially available control electronics or electrohydraulic valves, Porsche’s advanced gearbox wouldn’t enter a series production vehicle until the 2000s. In 2008, the Porsche PDK appeared as an optional extra on the 911 series. Then, in 2009, the Porsche Panamera became the first Porsche to be fitted wit the PDK as standard.
“PDK is definitely a highlight of my 38 years at Porsche,” says Wüst. “There were many lovely projects, and this was one of the loveliest…A lot of what you work on ends up in the bin. But this is here to stay, I can feel it. This makes me proud. When I see a car with PDK on the road today, I know: a piece of me is inside that. And this is a wonderful development.”