Pursuing its involvement in top-class road racing, Citroën Racing has unveiled its new DS3 WRC, due to take part in the 2011 season of the World Rally Championship. Citroën DS3 WRC complies with the brand new regulations drawn up the FIA and is packed full of Créative Technologie.
The compact, dynamic and aggressive design of this ‘little racer’ immediately catches the eye – it has clearly been designed with winning in mind with its widened wings, redesigned bumpers and aerodynamic features. Built using the production body shell, the chassis has undergone many modifications to adapt the four-wheel drive transmission and the McPherson-strut suspension system. The safety of the driver pair is guaranteed by a roll cage, which enhances the sturdiness of the car.
Compared with the previous generation of World Rally Cars, the 2011 regulations have led to a genuine revolution under the bonnet. Citroën DS3 WRC is powered by a four-cylinder, 1600cc turbocharged direct injection engine. A first at this level of motorsport, the use of a direct injection engine opens up new possibilities for the development of racing engines, especially in terms of fuel consumption. Designed and built from start to finish by Citroën Racing, this engine develops a healthy 300bhp.
The bodywork has been extensively tested in the windtunnel by Citroën and the panels a mixture of polycarbonate and filled with foam to improve crash protection properties and also weight reduction.
Built using the DS3 production body shell, the DS3 WRC chassis includes a roll cage made of over 40 metres of steel tubing. The lower part has undergone several significant structural modifications:
Upper attachment points added for the rear McPherson-strut suspension
Optimisation of the lower suspension attachment points
Integration of the transmission tunnel and the rear differential
Lateral reinforcements added level with the body sills
Since DS3 is more compact than C4 WRC, Citroën Racing’s engineers worked on improving the position of each component so as to achieve the best possible balance between the car’s centres of inertia and centres of gravity.
ENGINE: THE DIRECT INJECTION REVOLUTION
Since ground link system regulations have only undergone minor modifications compared to the previous generation of World Rally Cars, design office engineers were able to make the most of their experience, deploying solutions that have proven successful on C4 WRC.
The McPherson-strut front and rear suspension systems have latitude that enables the position of the attachment points to be optimised. In order to keep development and running costs down, it is now only possible to certify one type of pivot. DS3 WRC uses the same part at the front and the rear, on both the gravel and tarmac versions. The struts are connected using an interface part that varies according to the version. Just like its big sister, the C4 WRC, the four-way adjustable shock absorbers (low- and high-speed compression and rebound) have been designed and built by Citroën Racing.
Slightly smaller than on C4 WRC in order to comply with the 2011 regulations, the 355mm (tarmac) and 300mm (gravel) brake disks at the front, and the 300mm brake disks at the rear, come with four-piston callipers. A water-cooling system improves the efficiency of the brakes on tarmac.
TRANSMISSION: FOUR-WHEEL DRIVE FOR ALL SURFACES
With special stages on icy Swedish roads, rough gravel tracks in Greece and smooth Catalan tarmac, DS3 WRC will need to cope with both varied and demanding road surfaces. Although it is without any electronic assistance, the four-wheel drive transmission has been designed to maximise performance in all conditions.
The 2011 regulations require constructors to select a supplier that has met the specifications drawn up by the FIA. They set the weight and price of each element. Citroën Racing has signed a technical partnership agreement with the French company, Sadev.
The six-speed sequential gearbox and the front differential are integrated in an aluminium housing. These are connected to the rear differential via a longitudinal drive shaft. The central differential is now prohibited, but a system may be used to disconnect the rear wheels when using the hydraulic hand brake. Semi-automatic, steering wheel-mounted controls are also outlawed, and have been replaced with a totally manual gearshift lever.
As with the engine, the lifespan of the gearbox increases with the 2011 sporting regulations. At one point in the season, teams must use two gearbox/rear axle assemblies for three rallies.
DS3 WRC is set to make its official competitive debut at Rally Sweden (10-13 February), the first round of the 2011 FIA World Rally Championship.
Structure Reinforced body with weleded, multi-point roll cage
Bodywork Steel and composite fibre
Type Citroën Racing – 1.6-litre turbocharged direct injection engine
Bore x stroke 82×75.5mm
Maximum power 300bhp at 6,000rpm
Maximum torque 350Nm at 3,250rpm
Specific output 188bhp/litre
Ditribution Double overhead camshaft valve train driven by timing belt
4 valves per cylinder
Fuel feed Direct injection controlled by Magneti Marelli SRP-HP unit
Type Four-wheel drive
Gearbox Sadev six-speed sequential
Differential Front and rear mechanical, auto-locking
Front Ventilated disks, 355mm (tarmac) and 300mm (gravel)
Water-cooled 4-piston callipers (tarmac)
Rear Ventilated disks, 300mm
Distribution Adjustable from cockpit
Handbrake Hydraulic control
Front McPherson type
Rear McPherson type
Shock absorbers Citroën Racing four-way adjustable shock absorbers
(low- and high-speed compression and rebound)
Tarmac 8x18’’ wheels
Gravel and snow 7x15’’ wheels
DIMENSIONS, WEIGHT AND CAPACITIES
Wheel base 2,461mm
Track 1,618mm (front and rear)
Fuel tank 75 litres
Weight 1,200kg with driver pairing (regulations)