page_title: Mercedes-Benz CLR
section_title: Development
hierarchical_section_title: Mercedes-Benz CLR / Development
caption_attribution_description: English: Mercedes-Benz CLR
context_page_description: The Mercedes-Benz CLR was a set of racing cars developed for Mercedes-Benz through a collaboration with in-house tuning division Mercedes-AMG and motorsports specialists HWA GmbH. Designed to meet Le Mans Grand Touring Prototype regulations, the CLRs were intended to compete in sports car events during 1999, most notably at the 24 Hours of Le Mans which Mercedes had last won in 1989. It was the third in a series of sports cars raced by Mercedes, following the CLK GTRs and CLK LMs that had debuted in 1997 and 1998 respectively. Like its predecessors the CLR retained elements of Mercedes-Benz's production cars, including a V8 engine loosely based on a design used in some models as well as bodywork based on the CLK and CL-Classes. The CLR's bodywork was lower in overall height than that used on the CLKs to produce less drag.
  Three CLRs were entered for Le Mans in 1999 after the team performed nearly 22,000 mi of testing. The cars suffered aerodynamic instabilities along the circuit's long high-speed straight sections. The car of Australian Mark Webber became airborne and crashed in qualifying, requiring it to be rebuilt.
context_section_description: Work on designing a new car to meet LMGTP regulations began in September 1998 as Mercedes was closing out its second FIA GT Championship season.  Development was led by HWA GmbH, the motorsports division of AMG, which became an independent company the following year.  The LMGTP rules did not require road versions of the cars to be built, so Gerhard Ungar, chief designer for HWA, was free to develop the CLR without concern for road legality issues or the inclusion of driver comforts.  The transition from GT1 to LMGTP also allowed a decrease in the minimum allowed weight, from 950 kg (2,090 lb) to 900 kg (2,000 lb).  The new design had a much smaller cockpit monocoque made from carbon fibre and aluminium honeycomb.  The monocoque derived the design of its lower half from the CLK LM's combination of carbon fibre and steel tube frame, but required a full carbon and aluminium upper half because of new load tests mandatory for LMGTP cockpits.  The bodywork of the CLR was also 10 cm (4 in) shorter in overall height compared to the CLK LM, while the nose was substantially lower and flatter than its predecessor due to a shorter wheelbase allowing longer overhangs.  Aerodynamic development on the design was carried out at the University of Stuttgart's wind tunnel and assisted by the aerodynamic specialists Fondmetal Technologies.  Aerodynamic emphasis was placed on low drag for maximum top speed.  Mercedes-Benz's brand image was also retained with the reuse of CLK-Class tail lights from the CLK LM and a front grill and headlights based on the then-new CL-Class.
  The engine for the CLR was also a variant of the design used on the CLK LM. The GT108C 32 valve naturally aspirated V8 engine was loosely based on the M119 engine used in Mercedes-Benz road cars at that time.  A previous variant of the M119 had won Le Mans for Mercedes in 1989.  Displacement was increased from 5.0 L (310 cu in) to 5.7 L (350 cu in) to compensate for the new air restrictor limitations in the LMGTP category, which allowed the engine to produce approximately 600 bhp (450 kW; 610 PS). The first engine was completed and began testing in December 1998. The Xtrac 6-speed sequential gearbox came directly from the CLK LM, while Bridgestone continued as the team's tyre supplier. The suspension setup from the CLK LM was largely carried over to the CLR, although a central spring was added to the rear suspension.
  Mercedes publicly announced its CLR programme in February 1999 just days before the first car began private testing at California Speedway in the United States.  Testing continued into March at California as well as Homestead-Miami Speedway in Florida before the team moved to the Circuit de Nevers Magny-Cours in France.  At Magny-Cours three CLRs completed a 30-hour test session covering 8,073 mi (12,992 km).  On 20 April the CLR was shown to the press for the first time during a test session at the Hockenheimring in Germany.  By that point in the development process the CLRs had covered 21,735 mi (34,979 km) in testing without any major failures.
caption: The low profile of the CLR
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