Renntech has built a special one-of-one W140-chassis Mercedes-Benz S-Class to show the world what it’s capable of. Under the hood of this already classic 1992 Mercedes 600 SEL is the largest displacement M120 V12 ever built at 7.6 liters pumping out 615 hp (458 kW) to the rear wheels only. Here’s a detailed look at one of the slickest pieces of rolling advertising we’ve seen this year.
For the unaware, Renntech is a performance engineering firm founded back in 1989. Since then, it’s created some of the most overbuilt modified Mercedes models ever. At its helm is Hartmut Feyhl, a man with 12 years of job experience at AMG before spending time as the North American division’s technical director. He knows how to make a Mercedes even faster than it already was and the S76R is what Renntech is calling the “perfect W140.”
Read More: Making a W221 out of a W140 Mercedes-Benz S-Class
Under the hood of the S76R is a heavily modified (yet still naturally aspirated) version of the 600 SEL’s 6.0-liter V12 that was bored and stroked out to 7.6-liter. It’s aided by a ME-1 engine management conversion installed together with a handmade wiring harness and RENNtech ECU tune. The result is a healthy boost from the stock V12’s 402hp (408 PS) and 428 lb-ft (580 Nm) to 615 horsepower and 703 pound-feet (952 Nm) at the crank.
Renntech didn’t stop there as the original model’s 4-speed automatic was swapped out for 5-speed auto transmission, and an OS Giken limited-slip differential. Renntech says that with these mods, the 4,800 lbs (2,177 kg) German sedan can hit 60 mph (96km/h) in the low 5-second range while topping out at around 155mph (250 km/h).
To aid in the experience, Renntech has added some supporting modifications to the S76R as well. They include a custom, handmade stainless steel exhaust system with quad mufflers and sport catalytic converters that not only increase power but give the V12 a louder and meaner snarl as well.
The car was fitted with a bespoke AMG Carbon Ceramic braking system with six-piston calipers on the front axle and four-piston calipers at the rear. At the same time, it rides on one-of-a-kind forged Renntech aluminum wheels measuring 19 x 9″ in the front and 19 x 10.5″ in the rear with 235 / 45 (F) and 285 / 35 (R) Michelin Pilot Sport 4 S tires.
Inside the cabin, there’s a completely custom interior and trim set. Above the occupants is an Alcantara headliner with carbon fiber inlays. A leather dashboard sits ahead of everyone and the seats are finished with diamond-stitched leather upholstery. The rear bench seat has been replaced altogether with a pair of fully adjustable individual rear seats. Renntech has even added a modern sound system with iPhone integration.
While this example is a one-off, Renntech says it will happily build your own custom W140 Mercedes S-Class with all these mods and more, though it did not provide any details on pricing.