2007 Citroen C4 WRC

The Citroën C4 WRC - Citroën Sport’s new weapon - will be premiered on 5 September. Before making its debut in the World Rally Championship (WRC) from 2007, it is set to be one of the main attractions at the 2006 Paris Motor Show (28 September - 15 October).

The C4 Citroën Sport concept car was a vehicle symbolising the renewal of the Marque. It was the result of cooperation between engineers from the styling and sports departments. In the first instance, the project completely disregarded regulatory requirements. A true exercise in style, it met the challenge of developing a futuristic vision of a new car. A car to replace the Xsara WRC, winner of three world "manufacturers" crowns between 2003 and 2005. In the expert hands of Citroën Sport’s engineers at Versailles Satory, the C4 Citroën Sport concept car became the C4 WRC. 

Citroen C4 WRC

Adapting to regulations


Although the overall styling was maintained, the car had to be adapted to international regulations and performance requirements. This is where the design office of Citroën Sport stepped in. The project working group came up with a first rolling model of the Citroën C4 WRC that was already a long way from the original concept. The roof, for example, was no longer made of glass, since this is banned in rally racing. The front and rear wings, bumpers and spoiler were modified to satisfy regulations and performance criteria. To save time and money, a number of body parts were studied in wind tunnels on a scale of ¼ before validation of the full-size parts at the end of the project.

The main lines of the development programme


The role of the development programme was to validate the parts and powertrain sub-systems developed by the design office. Reliability was the first factor and performance the second. To achieve the desired result, several working sessions were necessary on both asphalt and gravel. The technical team of Citroën Sport then compared the performance of the C4 WRC with that of the Xsara, which remained the standard, the absolute reference. Although it is still in its development phase, the Citroën C4 WRC has shown real potential. Now, its performance can only truly be confirmed in rally conditions.

-Expectations and objectives

Citroen C4 WRC

The mechanics, engineers, crews and managers of Citroën Sport, are impatient to see how the C4 WRC performs in an actual rally event. Designed to be as easy to drive and as reliable as the Xsara WRC, the C4 WRC aims to set even higher standards of efficiency and performance. A car built and developed to enable Citroën to target the "drivers" and "manufacturers" titles once more from 2007.

Main technical characteristics of the Citroën C4 WRC


Like the Xsara, its glorious predecessor, the Citroën C4 WRC features four-wheel drive and a 2-litre turbocharged engine mated to a cross-mounted 6-speed gearbox. At 4.20 m, the C4 WRC is longer than the Xsara and, in line with regulations, therefore has a larger width of 1,800 mm, compared with 1,700 mm for the Xsara. This change should provide better stability on bends.
As also laid down in the new regulations, the use of electronic driving aids is limited, in the same way as for the Xsara in its 2006 configuration. Referring again to the regulatory budget cuts, the sub-systems of the C4 WRC – such as the engines, gearboxes, front, central and rear differentials and dampers – must last longer and be more reliable.

Citroen C4 WRC

Technical characteristics of the Citroën C4 WRC


Engine

  • Turbocharged
  • Developed from the XU7JP4 engine
  • Layout: crosswise, tilted 25° towards the exhaust
  • Number of cylinders: 4 in line
  • Aluminium block
  • Capacity (cm3): 1,998
  • Max power (bhp – rpm): 315 at 5,500
  • Max torque (mkg – rpm): 58 at 2,750

Timing

  • 2 overhead camshafts driven by a toothed belt
  • 4 valves per cylinder

Power supply

  • Magneti-Marelli multipoint injection
  • Type: 2KR

Transmission

  • 4WD
  • Carbon three disc clutch
  • Mechanical differentials on the front and rear axles – electronically controlled at the centre
  • Sequentially controlled 6-speed semi-automatic gearbox


Front brakes

  • Asphalt: ventilated discs, 6-pot callipers
  • Gravel: ventilated discs, 4-pot callipers

Rear brakes

  • Asphalt and gravel: ventilated discs, 4-pot callipers
  • Front/rear distribution adjustable by a compensator
  • Hydraulic handbrake

Suspension

  • Front and rear: MacPherson type with coil spring
  • Citroën / Exe-TC dampers

Steering

  • Hydraulic power assisted

Wheels

  • Asphalt: 8 x 18 inch
  • Gravel: 7 x 15 inch
  • Goodrich Asphalt BF tyres: 225/40-18
  • Goodrich Gravel BF tyres: 215/65-15

Dimensions

  • Length: 4,274 mm
  • Width: 1,800 mm
  • Wheelbase: 2,608 mm
  • Front/rear track: 1,598 mm

Weight

  • 1,230 kg (minimum authorised)

2 comments:

Citroen already has a C4 (not the 2007 model) car in the WRC diven by Sebastien Leob

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