I adore a compound German word, and Doppelkupplungsgetriebe is a cracker. Double-clutch gearbox. Which is what it suggests, or PDK for quick when speaking about the Porsche one particular. And the tale of the PDK commenced more than 40 a long time ago. Rainer Wüst was the person at the helm of its growth programme, and at the time he was the tender age of 35. “The plan,” he says, “was to incorporate the very best of two worlds – the strengths in the diploma of efficiency of a handbook transmission and the prospective for general performance of complete automation, which still experienced a lot of weaknesses at the time. It was a massive problem for a compact division such as ours. It’s possible it was naivety that aided us, but definitely our pragmatism in dealing with the worries did – as perfectly as our passion for this subject matter.”
Let’s begin with the principles of the PDK. The gearbox is break up in to two sub-transmissions, and each individual has its possess clutch. Only one of the clutches is ever engaged at any a single time, which means subsequent equipment can already be selected in the 2nd sub-transmission. To adjust gear, the manage device only opens the clutch that was transmitting travel, while simultaneously closing the one particular that wasn’t. That’s all which is necessary for a rapid and seamless change. Seems basic, doesn’t it? Properly, the journey was everything but.
The starting off point was when Wüst uncovered some outdated prototype advancement transmissions languishing in storage. These have been the get the job done of engineer Imre Szodfridt, who, late in the ‘60s, experienced pitched the notion of a twin-clutch transmission to the Head of Improvement at Porsche. He was a fella identified as Ferdinand Piëch. “Szodfridt was a really intelligent guy, so this preliminary function aided us,” Wüst remembers. This was a welcome spring board, then, but Wüst continue to had a sizeable hurdle to surmount: early ‘80s know-how.
“There were neither potent control electronics nor car or truck-compatible electrohydraulic valves in series creation. We obtained the Szodfridt transmission from storage and labored with pneumatic valves, which we transformed to get the job done hydraulically. It was intricate revolutionary function from the floor up, but the end result already had pre-sequence standing,” he claims.
The testbed for this surprise ‘box was the Porsche 944 Turbo, but the Porsche philosophy of screening in motorsport meant the new PDK was soon out on keep track of in a 956. The racing motorists weren’t sluggish to recognise its possible. Hans-Joachim Stuck factors out, “We ended up capable to transform gears and travel significantly quicker with out interrupting the engine’s generate.” And it was Trapped who came up with the novel notion of putting paddle shifters on the steering wheel. “Being capable to retain my hands on the steering wheel when modifying gears at full throttle felt good right from the start off.”
In the meantime, Jacky Ickx found out yet another benefit: currently being able to left-foot brake while accelerating with his correct foot to preserve the turbo boosting. “This built him noticeably more quickly coming out of a corner,” suggests Wüst. Of class, there were also the apparent gains of being able to change up faster for improved acceleration and maximising the pace down the straights. Faster downshifts also meant shorter braking distances. It minimised human mistake, much too the PDK wouldn’t overlook shift and danger popping the engine.
Continue to, there were some issues to address. The smoothness of the gearchanges for one particular, which was unsettling the racing automobile in the course of variations. The clutch control was not extremely smooth, so each time the driver shifted a gear there was ‘a significant jerk.’ And in accordance to Wüst, those jerks also “put fantastic strain on the transmission – and the total driveshaft. On a handful of instances, this excessive torque despatched all the things traveling around us, and I sat at household in the evenings and just about gave up on the entire factor.”
He didn’t give up, of study course. He tested a advancement PDK in the 962 with minimized transmission inertia. This was the to start with racing automobile with a PDK, and, in 1986, Derek Bell broke its successful duck with victory in the 360-kilometre race at Monza. In the exact same yr, Bell and Stuck went on to gain the Environment Sporting activities-Prototype Championship, as well. There was rallying results as well. An Audi Activity-Quattro S1, total with a PDK and one particular Walter Röhrl at the wheel, grabbed prime honours in the 1985 Semperit-Rallye.
These successes proved the technical strengths of the PDK in motorsport, but what about collection creation? Wüst states, “We were at least 20 a long time in advance of our time. Alongside with the improvement of valves and electronics, which were not sufficiently superior for sequence generation, the disorders have been not in location but for the deployment of the needed wet clutch.”
So we leap to the 2000s, by which time Ferdinand Piëch was the boss of Volkswagen and, according to Wüst, a man who “never forgot everything.” And obtaining recalled the examination programme at Porsche all all those several years ago, he facilitated what was now a perfected racing technology through to road cars. In 2008, Porsche changed the 911’s optional Tiptronic torque converter car with the alternative of a PDK. A yr later on it was equipped it as standard to variants of the Panamera.
Wüst is now Porsche’s Chassis Head of Growth, but he receives really emotional about the PDK a long time. “PDK is certainly a highlight of my 38 yrs at Porsche. There were being several wonderful jobs, and this was a person of the loveliest. A ton of what you operate on finishes up in the bin. But this is here to continue to be, I can feel it. This would make me very pleased. When I see a motor vehicle with PDK on the highway right now, I know: a piece of me is inside of that. And this is a amazing improvement.”