Back before AMG was owned by Mercedes-Benz, anyone with deep pockets could send their Mercedes to AMG for a la carte modifications which ranged from aesthetics to mechanicals. These pre merger AMG's, as we refer to them today, carry a lot of prominence and value. Once the official purchase of AMG had begun in the early 90's, Mercedes began to standardize the AMG offerings of each model and the days of custom outfitting your Mercedes were gone. Or were they?
One of the former AMG Germany employees, Hartmut Feyhl, decided to branch out on his own and founded RENNtech in 1989. This meant that Hartmut could continue to build mind-blowing builds for customers willing to pay for top-notch craftsmanship and quality. Hartmut spent 12 years at AMG Germany before serving as the North American division's Technical Director for AMG Central so he's revered as one of the most knowledgable Mercedes tuning specialist in the world. RENNtech has certainly made a name for themselves with record-breaking builds that not only produce outrageous performance numbers, but also do so with reliability. This 1993 SL740 RENNtech is one of those builds.
This 1993 SL740 RENNtech was previously featured in the September 1997 issue of MotorTrend Magazine and is now headed to auction with Bring A Trailer. This R129 began life as a 600SL but sometimes the top just isn't high enough. To reach 7.4 liters of displacement, RENNtech bored each cylinder to 91mm from 89mm and increased the stroke from 80.2mm to 95mm. The radiator is also upgraded along with the addition of an external oil cooler to keep things in line. A full stainless steel exhaust helps to increase air flow and capture the raw sound of the potent V12. The valve body is upgraded to provide 1st gear start and an ASR defeat switch added. The result increased horsepower from 389 to 575 and torque is now rated at 584 lb-ft. The car is accompanied by receipts from RENNtech (viewable in the gallery below) showing the price one had to pay in 1996 to have black magic performed on their M120.
The M120 engine is known for being silky smooth in it's power delivery and seems to only get stronger the faster you go. This SL740 launches from 0-60mph in only 4.4 seconds which was staggering in 1997. Keep in mind, while the car is a convertible, it still weighs over 4400 pounds. The quarter mile was covered in a mere 12.7 seconds at 114.2 mph when tested by MotorTrend. At the time, this was the fastest street-bound vehicle with an automatic transmission that MotorTrend had ever tested.
Additional modifications include 14" front and 12" rear Alcon brakes, lowered and stiffened suspension with additional links, oversized anti-roll bars, limited slip differential, and paint-matched O.Z. Racing Futura wheels. On the exterior, RENNtech incorporates an additional hood vent to assist with air flow. The headlights have also been upgraded to OEM xenon housings. The car still wears it's original Mercedes body kit and the interior remains largely stock aside from the steering wheel by RENNtech.
The car now sits with 52,750 miles which is still very low, especially considering the car is 27 years old now. We're pleased to see the car still appears original as to how it left RENNtech's facility. The 7.4 is at the top of the food chain and we expect this car to do very well at auction. The opportunities to purchase a car like this are few and far between so we'll be watching this auction which is now live with Bring A Trailer closely!