Just about everyone and their mother makes a Porsche 911 restomod, most following the template set out by Singer, blending modern engineering with absolute reverence for the past. But over in the Netherlands, KCPerformance does something different. It built a 993 with a PDK transmission.
And this isn’t a full drivetrain swap. Their 993 retains its original air-cooled flat-six, albeit modified both to work with the new transmission. KCPerformance builds all sorts of restomods beyond Porsches for individual customers, but it also works with other shops. Its experience doing modern electronics for air-cooled 911 engines took it down this particular path.
Kazimir von Hooijdonk, one of the co-founders of KCPerformance, felt that some higher-powered old 911s left a bit to be desired. When you go up in power, you need a stronger clutch, and almost invariably that means a heavier pedal action. He’s not a fan, and he suspects customers aren’t either.
"We have a couple of clients that have those 911s and 964s as well, and they just park them in the garage and they don't drive them," he tells Motor1. "Sometimes they drive them like on Sunday to do a quick tour, but they never drive them during the week."
A shame, in his view. Cars are meant to be enjoyed. The shop has a lot of experience swapping ZF eight-speed automatics into older cars, so the thought of pairing Porsche’s excellent modern dual-clutch transmission with an air-cooled 911 felt natural. The benefits are the same as choosing PDK over a manual in a new car—more performance, more usability, and to a lesser extent, better gear ratios.
But getting it to fit is complicated. KCPerformance designs and mills its own adapter plate to mate engine and transmission. Von Hooijdonk says that any good shop with an engineer proficient in SolidWorks can design things like this, but not many can do CNC work that’s precise enough to actually make the aluminum part. KCPerformance also fits a new flywheel with an integrated crankshaft position sensor, and an electronically controlled throttle body. The throttle itself is a Porsche part, but the pedal comes off an E90-generation BMW 3 Series. KCPerformance has a big BMW business, so it’s familiar with the automaker’s extensive parts catalog. The E90 pedal just happened to fit well.
Still, there’s a lot more to the project than just bolting everything together, and this is where KCPerformance’s expertise helps. In addition to the electronic throttle, KCPerformance fits the engine with modern fuel injection and electronic ignition, plus a handful of other sensors. An aftermarket ECU running a custom map directs the conversations between the engine and transmission. This obviously enables the whole system to work, but it also provides for a ton of flexibility. You can make “comfort” and “sport” throttle maps, and if you ditch the stock Porsche transmission controller, you even set up how the transmission itself shifts.
“If you look at the gearbox in [a GT3 RS] car, they slam it in gear. We can do the same thing,” von Hooijdonk says. On the flipside, KCPerformance can also make shifts feel as smooth as those in a regular 911 Carrera.
If you want a stock look, KCPerformance can make the system work with the original Tiptronic gear lever, or fit the more modern PDK lever. You can shift manually with the Tiptronic rocker switches on the steering wheel, too.
The PDK also opens up some interesting possibilities. All that extra hardware added to the engine enables the use of modern traction control, and the shorter ratios of the seven-speed gearbox can influence engine tuning. While KCPerformance did its first PDK conversion with a 993—Von Hooijonk’s favorite of all the air-cooled 911s for its modernity—any air-cooled 911 can be so equipped. The shop is even building an all-wheel drive 930 Turbo with PDK for a client, and that car will even get the ABS system off a BMW E46 M3.
It took KC 1,500 hours to realize this first PDK swap, but now that the hard work has been done, future cars will take far less time. Von Hooijdonk says that even creating engine and transmission maps should only take a couple hours on the dyno, since KCPerformance already has a baseline to work with thanks to this 993. Still, it’s not cheap. Figure around €50,000, depending on how you want it configured.
At the end of the day, it’s about drivability. "I think the difference between us and a lot of companies is that we want you to be able to hammer [the car] all day, every day and drive it to work without fail,” von Hooijdonk says.
The company prides itself on the unusual, too. Plenty of restomod shops can take off-the-shelf parts and put them in an old chassis and call it good. KCPerformance does real R&D.
