At the beginning of 2020, the new generation of the US sports car Corvette will be hitting the market with a surprise: For the very first time, a mid-engine in the rear propels the American icon. General Motors awarded the development and production of ventilation grilles to sheet metal specialist Graepel.
The German supplier has confirmed the start of production for the final assembly of Chevrolet's sports cars in Kentucky.
GM relied on an engine in the front of the vehicle for a long time. The new V8 in the top model Stingray delivers 364 kW (495 HP) from a displacement of 6.2 liters. Two large grilles in the powerful rear hood ventilate the engine, which accelerates the car from zero to 60 miles per hour (100 km/h) in about 3 seconds. The air outlets—like no other component—is the focus of the amazed observer: The components are positioned on both sides of the hood window insert, which gives a clear view of the powerful engine block – this is where the heart of the Corvette beats. The requirements in terms of precision were very high, but so were the demands for aesthetics.
The supposedly banal perforated sheets posed a real challenge for the suppliers. “Top quality cannot be achieved with simple punching methods,” emphasizes Mark Zumdohme, Chief Executive Officer of the US plant. He points to the crux of the design: The grilles must be light, but stiff in every web. In addition to it, it should be one piece, neatly shaped and gracefully designed. "And the air flow rate, the main technical characteristic, should be at a maximum," adds Zumdohme. Graepel achieved a free cross-section of over 80 percent: a phenomenal value.
The sheet metal specialist achieves this through complex forming operations, precise high-speed presses and program-controlled punching operations. The holes are not circular, but hexagonal: A bionic shape that features an excellent distribution of forces. And the aluminum sheets are only 1.2 mm (0.05”) thick. Another grille is supplied for the middle section of the rear bumper.
Graepel is one of the pioneering manufacturers in the industry. The company’s beginnings go back more than 125 years – to the beginning of industrial automobile production. Not like any other company, Graepel specializes in perforated and cold-formed sheet metal components. The company even develops its tools in-house. The US plant in Omaha, Nebraska, exists since 2006. By the way, the Chevrolet Corvette project is not the first of its kind: Graepel also supplies for the Honda/Acura NSX sports car.