On a hot and humid night in May, RENNtech arrived at Palm Beach International Raceway’s drag strip with a brand-new Mercedes-AMG GT 63 S 4-door Coupe. The menacing family “sedan” had left the factory in Affalterbach, Germany, with the AMG developed 4.0L (M177) twin-scroll BiTurbo V8 engine 681 HP and 736 lb-ft of torque (dyno measured by RENNtech), but since arriving in the United States, the car had benefitted from RENNtech’s engineering and know-how for developing some seriously fast Mercedes-Benzes in Stuart, FL.

True to their go-fast(er)-philosophy, this GT 63 S had been upgraded with RENNtech’s R2Performance Package. Including ECU, Turbo, Fuel System upgrades, Downpipes, Blow Off Valves, and BMC Air Filters, RENNtech had raised the power output to an incredible 875 HP and 873 lb-ft of torque!! Increasing the power output by 194 HP and 137 lb-ft of torque on a highly tuned AMG engine is a remarkable feat and passing the 800 HP mark offered new challenges for the RENNtech engineers.

First, RENNtech had to develop a Fuel Delivery system capable of raising the volume to match the increased power created by the upgraded turbos. Second, to remain “street-spec” the car had to perform on readily available pump gas, because that is how RENNtech sees their customers using the car. Testing product upgrades with high octane racing fuel, volatile Nitrous Oxide or highly flammable Methanol, does not fit RENNtech’s modus operandi of developing race technology for daily street use.

A few weeks earlier RENNtech had tested the GT 63 S with their plug-and-play HHT ECU upgrade (783 HP and 798 TQ) and set a record time of 10.652 seconds @ 127.38 mph with a flip of a switch. Now, with an additional 92 HP and 55 lb-ft of torque breaking the mid 10-second mark was the target but certainly not a given, and on this muggy Florida night the dyno measured figures were about to turn into real-world results.

RENNtech has been the leader in Mercedes-Benz and AMG tuning in the United States since 1989, and its Owner and President, Hartmut Feyhl, takes the engineering and development of performance tuning very seriously. As the AMG GT63S R2 crept toward the starting line, the mood of the RENNtech crew was noticeably tense, after all, the results of hard work and their reputation as the number one Mercedes-Benz AMG tuner was on the line.

With Feyhl behind the wheel the GT 63 S R2 roared down the lane and lit up the timing board at 10.479 sec at 130.87 mph. Seriously fast, and a new record as the fastest AMG GT 63 S 4-Door Coupe running on readily available pump gas (tested with 93 octanes in FL).

When asked about the result, Feyhl answered in his German matter-of-fact way. “The car performed excellent, but it can go even faster. With a change in temperature, or DA (Density Altitude), our customers will experience faster times. A hot and humid Florida night like tonight is like driving through soup.”

For everyone at RENNtech, as well as their band of loyal customers, the night was a success. Erasing their own record by creating a new one measured both progress and performance, while proving that RENNtech is on top of their game.

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