RENNTech Gives Us All The Details On The S76R’s Bored And Stroked 7.6-Liter V12

We recently reported on what RENNTech calls the largest displacement V12 on record for the Mercedes Benz M120 engine. The naturally aspirated 7.6-liter V12 with its 615 hp (458 kW) is just the icing on the cake of what is a truly stunning bespoke super sedan in the S76R. We were so mesmerized by it that we reached out to RENNTech with questions and they gave us details you won’t read about elsewhere.

This isn’t just an old W140 S-Class with a big tuned engine inside in place of the 6.0-liter unit that used to make 402 hp (299 kW). It’s a custom creation RENNTech built for a customer and as a demonstration of just what the firm is capable of. It comes complete with a bevy of supporting modifications like stronger connecting rods, better brakes, and a completely new exhaust system.

RENNTech’s Lars Totterman told us that every performance upgrade in the S76R is also lighter than the OEM part. The carbon ceramic brakes, the exhaust, and the suspension are all included in that list of components. RENNTech says that each individual 92 mm piston with its titanium connecting rod is 358 grams lighter than OEM. Multiply that by 12 cylinders and you get a savings of 4.3 kg (9.4 lbs).

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Despite those significant changes, weight reduction wasn’t the main goal of this car according to Totterman. “As a performance company reducing weight is always our goal, however with the S76R our goal was not a lightweight sports car rather a vehicle that preserves 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’s pushed up above 3,500 rpm.

We also asked about performance figures, like top speed and 0-60 times, which RENNTech says are coming in the future. For now, it’s in the middle of its break-in period so high-stress tests like that will have to wait. It believes that it’ll do the sprint in the low 5-second range and top out somewhere around 155 mph (250 km/h).

Finally, we wondered about the customer’s choice of a five-speed automatic transmission. Totterman says that the additional power created by the 7.6-liter V12 was simply too much for the original 4-speed to handle. The 5-speed 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 commission one. That also applies to the 6.0-liter V8 builds that the company creates.

You can take a look at the gallery right below documenting the build. It provides clear evidence of just how meticulous the S76R’s engineering really is.