This car was developed by Opel Performance and driven by Manuel Reuter in the German Touring car championship. Now it is driven by Ric Wood in the Dutch Supercar Challenge (2006 & 2007 seasons)
The awesome DTM Opel Astra V8 Coupe runs a 460hp 4-litre V8 combined with a light weight chassis to give excellent race performance. This car has competed at the highest levels in Europe and continues to compete well against a very strong and well funded fields in the DSC with some very good drivers.
Wind tunnel developed aerodynamics and carbon brakes give superb race handling and performance. Ventilated 380-millimetre carbon discs and six-piston aluminium calipers at the front, ventilated 340-millimetre carbon discs and four-piston aluminium calipers at the rear – this is the standard braking system for DTM race cars, supplied by UK specialist AP Racing. Anti-lock braking systems (ABS) are prohibited.
To give some idea of how this differs from standard cars, production vehicles achieve a maximum deceleration of 0.8 to 1.1g, DTM cars nearly reach 2.0g. And while the production vehicle needs about 40 metres to brake down from a speed of 100 km/h to zero, the V8 CoupО needs only 25. This high level of braking power is the result of the ratio between vehicle weight, the road-holding capability of the standard Dunlop tyres and the energy transformed by the brakes. To illustrate this point, accelerating the Opel Astra V8 CoupО with a mass of 1,150 kilograms – including driver and fuel – to a speed of 200 km/h requires a distance of 200 metres and takes 6.4 seconds, thanks to about 350kW of engine power. Decelerating the same vehicle, however, only requires a distance of 63 metres, which equates to the braking system absorbing about 1,100kW of power in the process. This in turn means that 1.1 megawatts of power are transformed into heat within a mere 3.6 seconds!
One of the major development objectives for the DTM Astra was a notable increase in aerodynamic efficiency, calculated in terms of down-force and drag. The coefficient of drag which, in the production Astra CoupО reaches an excellent Cd-value of 0.28, has clearly been raised for the racing CoupО, owing, for example, to enormous wheel arch extensions, but also to air ducts for cooling water, oil, brakes and gearbox.
The impact of these air ducts on drag and down-force, resulting from such factors as the location and design of the air intakes at the front apron must be kept at an absolute minimum.
Extensive simulations helped create a 40-percent scale model of the racing Astra used for investigating air flow and down-force behaviour in the wind tunnel of Fondmetal Technologies in Italy. Because DTM regulations only allow one particular aerodynamic configuration per racing season, these investigations were soon followed by wind tunnel tests of the original vehicle at the University of Stuttgart and, of course, on the track itself.
The wind tunnel in Stuttgart is currently rated as one of the world’s most advanced facilities, enabling road simulation tests of vehicles up to a speed of 250 km/h. This is accomplished by five air-cushioned steel running-belts, one between the wheel track and four for driving the wheels. Velocity plays a decisive role, because the aerodynamic forces rise at a square relative to the increase of speed. Consequently, doubling the speed from 100 to 200 km/h quadruples the aerodynamic forces that come into play.
Aerodynamic forces lead to higher wheel loads, which means that higher forces can be transmitted via the tyres. This results in higher cornering speeds, better braking deceleration and higher traction when accelerating from corners.
The rear aerofoil is the most conspicuous aerodynamic component. The restrictive technical regulations of the DTM prescribe both the spoiler profiles and their position. A considerably higher developmental effort is invested in the air flow underneath the vehicle. While a flat underbody is mandated between the axles, the front splitters and the diffuser provide for ground effect.
Based on a carefully crafted shape worked out in wind tunnel tests, the air underneath the front spoiler is accelerated, with the higher air flow velocity creating a suction or vacuum-like effect on the vehicle.
Front flaps located on the left- and right-hand sides of the vehicle front, which may be removed for performing the balanced vehicle set-up, increase down-force. The diffuser, which sucks out the air from underneath the vehicle, thus creating a suction or vacuum-like effect at the vehicle’s rear, works in a similar way to the front splitter. The wedge shape resulting from a change in the vehicle’s position through front and rear ground clearances is another major factor in this. The objective is to achieve an optimum of aerodynamic balance, resulting in driving behaviour that is as neutral as possible, without compromising optimal wheel load values.The definition of aerodynamic balance is derived from the distribution of the down-force coefficient to the front and rear axles.
One of the truly challenging aspects of racing a car like this is the configuration of the car for circuit and conditions. A minor change in ride height or front or rear down-force can make a huge difference to the way the car performs. As a race driver this makes the difference between competing and being on the podium. Ric Wood Motorsport know how to make that difference. It’s how we race and it’s part of the service we provide.