We recently reported on what RENNTech calls the largest displacement V12 ever registered for the Mercedes Benz M120 engine. The naturally aspirated 7.6-litre V12 with its 615 PS (458 kW) is just the icing on the cake of what is a truly stunning custom super saloon in the S76R. We were so fascinated by it that we approached RENNTech with questions and they gave us details you won’t read anywhere else.
This isn’t just any old W140 S-Class with a big tuned engine in it instead of the 6.0-litre engine that used to deliver 402 hp (299 kW). It is a custom creation that RENNTech built for a client and as a demonstration of what the company is capable of. It comes complete with a slew of assistive tweaks like stronger connecting rods, better brakes and an all-new exhaust system.
Lars Totterman of RENNTech told us that every performance upgrade in the S76R is also lighter than the OEM part. The carbon ceramic brakes, exhaust and suspension are all included in that list of components. RENNTech says each individual 92mm piston with its titanium connecting rod is 358 grams lighter than OEM. Multiply that by 12 cylinders and you get a saving of 4.3 kg (9.4 lbs).
Despite these major changes, weight reduction was not the main goal of this car, according to Totterman. “As a performance company, our goal has always been to reduce weight, but with the S76R, our goal was not a lightweight sports car, but a vehicle that retains the vault-like character and planted feel of the W140 S-Class,” he explained. He went on to say that the only time passengers hear the engine from inside the cabin is when it is pushed above 3,500 rpm.
We also asked about performance figures, such as top speed and 0-60 times, which according to RENNTech will come in the future. For now, it is in the middle of the break-in period, so such stress tests will have to wait. He believes he will do the sprint in the low range of 5 seconds and finish somewhere around 250 km/h.
Finally, we wondered if the customer had chosen a five-speed automatic. Totterman says the extra power from the 7.6-liter V12 was simply too much for the original 4-speed manual transmission. The 5-speed transmission is much more capable and has better ratios, he said. RENNTech is also happy to build an S76R with a 5- or 6-speed manual transmission, should a customer order one. So are the 6.0-liter V8 builds the company makes.
You can take a look at the gallery below to document the build. It provides clear proof of how meticulous the engineering of the S76R really is.