With more than 600bhp, weighing just 795kg and with a 0-62 time of 2.3 seconds, this SLK could possibly be the fastest Mercedes-Benz in the world, or at least on certain parts of it. That’s a weighty statement to make, but this car is built for the European Hillclimb Championship where there are rules to govern safety but not much else. Power is restricted only by traction, speeds are only limited by physics. If you can conceive it, if you can build it, then you can race it… and that’s just what Swiss driver Reto Meisel has done with this highly-modified Merc.
Reto lives and breathes the marque. His father opened a Mercedes-Benz dealership in the sleepy Swiss village of Leuggern in 1972. Some of his earliest memories are driving around in something his dad pulled off the forecourt, and at 16 years of age Reto’s higher education consisted of a four-year engineering apprenticeship at Mercedes-Benz in Zurich.
When he began to get seriously interested in motorsport, an M-B was the only car he considered, and an ex-DTM car no less: the 190 Evo II that Roland Asch raced in 1993. With this beautiful machine he took both the 2002 and 2003 Swiss Hillclimb championships, but with the pace of developing technology he needed something faster, as he says, “a proper race car!” He chose a 190 body again to start that build, but he put a Judd Formula 1 engine in it. With this car he won the German hillclimb championship in 2007, 2009, and again in 2011. By then the car was seven years old though, so for more speed and performance he needed a new project, and this is where the utterly unique beast pictured here came from.
As he needed a small current-model car with two doors to carry out his new vision, Reto he chose the SLK over the bigger and heavier C-Class coupe. A bodyshell was ordered from the factory, but nothing else, as for such a hyper-focused hillclimber there is not much use for anything found on the road-going version of this car. It wasn’t just the metal body he got from the factory though, as Reto also managed to procure a DVD full of CAD files. Normally this is something kept more or less top-secret, but a friend from back in his university days now works in the engineering department and managed to pull a few strings. This meant that with additional CAD files for the gearbox, paddle shift gear selectors, and the engine, very accurate renderings could be made of the interior and exterior elements. The design process was taken on by another good friend—an hour in the morning and an hour in the evening as he commuted to and from work on the train each day.
The first tangible pieces of the project came together in the form of the roll cage, as it’s both the safety cell and what everything else is mounted to. An incredible 90 meters of 25 pieces of chromoly tubing went into its construction by a company called Lockid in Germany and it’s a very specialized, very high-tech job; it has to be FIA-approved, so it wasn’t something Reto could do himself.
Modern Mercedes aficionados might already know that there wasn’t a 340 model designation for the SLK range, but that’s because under this hood there is a Judd 3.4L V8 out of a LMP2 car, so a slight name change was necessary. It’s a secondhand motor of course, but it only did one or two races before it had a complete rebuild and was put up for sale. At £65,000, it was still the single most expensive part of the project. It’s light, naturally-aspirated, and as Reto’s car is lighter than even the prototype endurance car this motor was made for, his SLK has—he says with a knowing smile—“exceptional performance.”
The gearbox connected to the high-revving V8 is from Hewland in the UK, and this particular unit has a sad story attached to it. “Georg Plasa was a best friend of mine who passed away a few years ago, and his brother was selling everything from his race shop. I took the gearbox and can say that is a very sentimental piece.” We recently shared the story of Georg’s rebuilt BMW E36 hill climb car, another Judd-powered monster.
Suspension on the Merc is a three-way adjustable setup from KW, and they feature race springs modified specifically for this car, as its quite a bit lighter than other race cars they would normally be fitted to. The valves in the shocks are a little different too, but Reto reminds me that its not unusual for top race car to have a specialized setup made just for it, and this discipline of the sport is certainly one of the more technical.
Since its completion the car has been raced in the E1 Hillclimb class, and the rules stipulate you must have the floor and A and B pillars of the original car, so the bulkhead, transmission tunnel, and the floor to just before the rear wheel arches is all original material in Reto’s SLK—everything else was superfluous and fell victim to the angle grinder. The rear light covers are original but just the outer plastic pieces are in place, as working lights are not needed for hillclimbs. In addition, the door handles are original parts, as is the three-pointed star on the front grill. The rest of the bodywork is made from fiberglass from moulds of the original panels, with the arches additionally sculpted to fit the huge racing tires: Avon 13×15 on the rear and 10×13 on the front, mounted on BBS wheels. The brake disks are made from ultralight ceramic composite material and for the short blasts up the hill the fuel tank has been reduced to a minuscule five-liter cell. The minimum weight for the class the is 780kg, and this car weighs 795kg at the moment I saw it, and Reto says that to take out that last 15kg will be a very expensive job given how bare it is already.
The most striking aspect of his SLK on first impression are obviously the massive bookshelf-sized wings and the diffuser to match. The design was done by a guy who has twenty years of experience building wings for race cars, but despite knowing what a competitive advantage getting the wings properly tuned by way of experience, time in a wind tunnel is still something he’d like to pursue. “It’s something I would like to try and arrange with Mercedes, but to do it right you need two or three different setups to test and analyze the data of, and I don’t have that many yet.” All three flaps in the massive rear wing on the car in these photos are adjustable, and each hillclimb course necessitates its own aero setup, naturally. When he gets around to it, all of the additional little winglets will be adjustable as well. Top speed isn’t as important as acceleration and cornering speed in hillclimb racing, so Reto won’t even hazard a guess as to what the car could get up to in a straight line—it’s not what it was designed for.
“But it all sounds too easy! But building this car was the hardest thing I’ve ever done in my life,” he says as we wait for the coffee machine to pour out another espresso. “It must be absolute heaven to work on a race car in a manufacturer’s team with a hundred people all under one roof having meetings every day, but with this being such an international build it was a crazy situation trying to bring everyone together to organize schedules, deadlines, and budgets. For example the paddle-shift system comes from Germany, the electronics for the engine is Motec from Australia, the mapping system for the dyno is from the UK. Sometimes one part was not finished and we had to wait two months because the next process couldn’t begin without it. And of course there were plenty of stupid little details that took up too much time. Also, in the background to all that we built new premises for the dealership, became the Swiss partner of Carlsson tuning and I did another engineering degree to become a master engineer. That’s why it took three years to get it to its first race. It was a very busy few years!”
In the time since these photos the car’s paint job has changed among other little things, but that screaming Judd mill is still the centerpiece—you all know the way to YouTube right?
