Hartmut Feyhl’s life and passion extend far beyond the cars RENNtech has engineered. Working closely with AMG in its infancy is an almost unimaginable privilege — yet Feyhl lived it. Today, he is the most important living link to AMG history in North America, holding the spirit of the pre-merger AMG era with an ultra high-quality, à la carte variety of performance solutions for Mercedes-Benz enthusiasts worldwide.
Hartmut Feyhl: The Legacy Behind RENNtech
A Legacy of Innovation
Fast forward 35 years later, innovation is at the core of RENNtech’s values as a brand. The tuning house is known for their rock-solid reliability, quality of craftsmanship, and innovative engineering solutions that go beyond engine tuning. Hartmut Feyhl believes that a holistic approach must be taken in order to ensure that his products do not simply move faster, but they perform better in every way imaginable.
RENNtech goes the extra mile to develop proprietary software and hardware solutions that seamlessly integrate with a vehicle’s telematics, unleashing the vehicle’s full potential. Suspension systems are refined, and aerodynamics are optimized in order to keep the vehicle secure on its course. RENNtech’s evolutionary pursuit of performance technology has paved the way for motorsports. In 2018, RENNtech Motorsports’ AMG GT4 raced its inaugural race at the Circuit of the Americas.
From Affalterbach to the World Stage
It’s a fascinating time to be alive for those who admire modern classic Mercedes-Benz and pre-merger AMGs. These cars are now both nostalgic icons and valuable collector’s pieces.
The Mercedes-AMG brand has evolved into a household name in performance, but discerning enthusiasts will also recognize another name: Hartmut Feyhl.
“The apple doesn’t fall too far from the tree.”
Hartmut grew up in Affalterbach, Germany — home to a small tuning company called AMG. As a young man, he enjoyed sports like shooting sporting clays and racing go-karts at the local track.
One day, after winning at the range, he was congratulated by Hans Werner Aufrecht, the “A” in AMG. The two discovered they shared a passion for both shooting and motor racing.
Hartmut was soon invited to apprentice at AMG, working directly with Aufrecht and Erhard Melcher (the “M” in AMG). From 1978 to 1986, Feyhl advanced from Technician to Master Mechanic and AMG Engineer.
Outside of the workshop, he continued racing — in go-karts and Formula Ford — believing that pushing vehicles to their limits was essential for understanding and improving them.
By 1986, Feyhl had become Technical Director for AMG North America.
The Birth of a Legend:
The Hammer
Feyhl played a major role in developing the W124 E 300 6.0 AMG, famously nicknamed “The Hammer.”
The first U.S.-spec Hammer (1987) featured a 32-valve head, producing 360 bhp and 400 lb-ft of torque. Its name stuck because in both English and German, “Hammer” implies raw power — Das ist Hammer! (“This is awesome!”).
Top Speed Glory
When Car and Driver invited Feyhl for the “Ultimate Top Speed Shootout,” he reached 300 kph (186 mph) with only subtle modifications. The magazine famously wrote:
“The Hammer covers ground so quickly that you swear you can feel the earth’s curvature racing to meet you.”
The RENNtech Era
In 1989, with Aufrecht’s blessing, Hartmut Feyhl founded RENNtech. The name blends the German word Renn (“race”) with “tech” for technology. His mission: bring bespoke racing technology to the street.
RENNtech’s first shop in Delray Beach, Florida quickly became known for its Hammer builds and R129 enhancements.
By 1990, the company had moved to a larger facility in Lake Park, FL. Feyhl evolved the Hammer formula, creating RENNtech 6.0 Hammers based on the M119 engine in the 400 E or 500 E chassis. Every car was built to customer specifications, making no two exactly alike.
