While GT3 vehicles are increasingly being driven by professionals in global GT racing, the GT2 class is primarily driven by so-called gentleman drivers: ambitious, semi-professional racing drivers. The Mercedes-AMG GT2 - with up to 707 hp the most powerful homologated racing car in the history of the Mercedes-AMG Customer Racing Program - is aimed at this target group. A racing suspension from thyssenkrupp Bilstein ensures precise drivability and maximum agility and performance.
The shock absorber manufacturer had to prevail against tough competition as part of a tender, as Timo Drüge, Sales Manager Performance & Motorsport, reveals. “For a long time, we were able to equip many of the fastest teams with our products. As a result, many other teams followed suit and also wanted the corresponding product.” However, the market situation has since changed. “Today's motorsport is characterized by strict homologation requirements,” says the engineer. These requirements are intended to ensure that racing vehicles comply with the technical and safety-specific rules and regulations laid down by the organizers of the various racing series. “Racing vehicles and their components must be homologated, i.e. approved for a specific racing series or class. As a rule, this also includes the shock absorbers. The homologated parts are then mandatory for the teams. Retrofitting them is only possible in a few exceptional cases.”
Especially in customer motorsport, where car manufacturers such as Mercedes-AMG, Porsche and BMW produce homologated racing cars in small series, factors such as performance, development expertise, testing and simulation know-how and cost efficiency are now of crucial importance. These are all criteria in which thyssenkrupp Bilstein has been able to make a decisive mark.
In order to create the best compromise in terms of performance and cost efficiency, the suspension specialists at thyssenkrupp Bilstein had a special idea: the concept was to adapt the high-performance BILSTEIN EVO RT 5-way racing shock absorber, with which the Mercedes-AMG racing cars in the particularly professional GT3 class have been celebrating international success for years, to the requirements of the Mercedes-AMG GT2. This resulted in a special challenge. After all, “the GT2 homologation status obliges Mercedes-AMG to install a maximum of a three-way system in the vehicle,” says Timo Drüge.
But thanks to the modular system architecture, with which the motorsport department at thyssenkrupp Bilstein designs its products, this was possible. While the 5-way shock absorber is adjustable in the rebound and compression stages, in both the low-speed and high-speed ranges (piston rod speeds from 0 to approx. 125 mm/s and over 125 mm/s) and also has a blow-off valve, downsizing was now the order of the day. The engineers reduced the five ways of the shock absorber system for the Mercedes-AMG GT2 to three. The newly developed BILSTEIN EVO RT 3-way racing shock absorber is adjustable in the rebound stage in the low-speed range and in the compression stage in the low-speed range and in the high-speed range. In this way racing teams can develop their own individual damper setups that are perfectly matched to the respective race track.
Timo Drüge is convinced that this is a significant competitive advantage: “The fact that we were able to adapt a high-end technology originally designed for the GT3 class for use in accordance with GT2 regulations was probably a decisive factor. Because one thing is quite clear: this is a highly potent damper system whose technology is unique in the GT2 sector. Both rebound and compression damping can be adjusted in the BILSTEIN EVO RT 3-way shock absorber in a range of ten precise clicks. “The manually adjustable controls have a very good feel from click to click - this also sets us apart from the competition,” says the Bilstein engineer.
The time factor posed a particular challenge during the development. “In motorsport, development projects are often very tight on time. This project was no different,” reveals Timo Drüge. This is where thyssenkrupp Bilstein was able to play another ace. “Our shock absorber prototypes were tested by Mercedes-AMG on various racetracks around the globe. Due to the tight time frame for the development phases, we developed the vehicle and our shock absorbers in parallel using our 7-post test rig at the Nürburgring.” This is a state-of-the-art vertical test bench with seven hydraulic rams, which simulates the driving behaviour of road and racing vehicles on a wide variety of track profiles and can be used to optimize the spring/damper design. Once again, the expertise of the Bilstein engineers and the ability to test chassis on the test bench at a very early stage of development proved to be key success factors. “This enabled us to significantly help the customer to reduce their testing costs,” says Timo Drüge. “In this way, expensive race track days can be saved because we can develop much more efficiently and selectively with the test bench.”
At the Nürburgring, for example, especially on the just about 25-kilometer combination of the Grand Prix circuit and the Nordschleife. “Most of the time, there are certain points on the racetrack where you want to analyze the behavior of the vehicle and optimize it accordingly. For example, a jump or a certain curb. At the Nürburgring, the driver always has to drive eight-minute laps to get to this point. This naturally drives up the costs. With our test rig, we can simulate the same spot and repeat it several hundred times if necessary - under exactly the same conditions, regardless of wind or rain. That's a very, very big advantage for us - and an important factor for getting the best out of it as a development partner.”
But before the time finally came, one last test had to be completed: The decisive approval test for homologation at the renowned Paul Ricard race track in France. The moment when everything was at stake. But the BILSTEIN EVO RT 3-way racing shock absorbers passed the final test with flying colors. “That was the decision for us to win the series,” says a delighted Timo Drüge. “We didn't know whether we would be awarded the contract until shortly before the start of production. As soon as the go-ahead was given, we received the order from Mercedes-AMG. And then everything had to go hand in hand again to keep to the ambitious timing,” says the sales engineer. But once again, thyssenkrupp Bilstein was able to impress - thanks to the close cooperation with colleagues from the Original Equipment (OE) division.