CITROËN RACING’S DEVELOPMENT OF 2017 WORLD RALLY CAR ACCELERATES IN FINLAND

With its large, fast and rolling roads, Finland is among world rallying’s most revered venues. Due to the high speeds and the difficulty to “read” the road, it is one of the toughest terrains to grasp, with the drivers needing to concentrate on the jump approaches that send the cars flying into the air.

It is, therefore, no surprise that this country figures among the priority destinations for the team in charge of developing the Citroën that will compete in the 2017 FIA World Rally Championship. After the rough terrain of southern France and the mud-filled tracks in Portugal, Finland was ideal to continue assessing the car’s reliability and performance.

For this test, the aerodynamics were closely scrutinised by the engineers. “The freedom allowed by the FIA regulations offers us a much larger range of possible solutions than before,” says project manager for the 2017 World Rally Car, Alexis Avril.

“The bodywork of the WRC must entirely cover that of the original model and the maximum width is set at 1875mm. In this framework, we have a lot of freedom to design the wheel arches and bumpers. We can also create air intakes for re-cooling the rear brakes and add on a diffuser. Paradoxically, there are more restrictions for the design of the rear wing than today, but its efficiency will be increased tenfold by its further backed and raised positioning.”

The aerodynamics of a race or rally car must solve the complex equation of attaining maximum down-force, minimum drag and maximum cooling. To achieve this, Citroën Racing’s engineers have adopted what is now a standard methodology.

“We started the work with the CFD calculations, which let us sift through the possible options, continues Alexis Avril. “We collaborated with the Citroën design studio in order for the race car to resemble the characteristics of the production model. From this data, we built a model that was used in the wind tunnel. Between sessions, we carried on with the CFD calculations in enriching the data from the tests, and vice versa.”

With this approach, the expertise gained during the development of the WTCC Citroën Elysée has been widely put to use: “We have made great strides in our understanding of the flow principles and aerodynamic performance since 2013 and the debut of the WTCC programme. We have saved time in utilising the proven solutions. As the disciplines are different not everything was transferable, in circuit racing, there is a form of systematisation that doesn’t exist in rallying. Thus, the compromises are more important.”

While the aerodynamic development itself was done with CFD calculations and wind tunnel tests, the test sessions were used to assess the resilience of various components. “Vulnerability is an essential point in rallying. The dirt, mud, stones and gravel can quickly tear away the element or block the air intakes,” recalls Alexis Avril. “So you have to run in all the conditions to find a compromise between reliability and performance.”

FOR FURTHER INFORMATION:

ANDREW DIDLICK
02476 884309
andrew.didlick@mpsa.com

JOHN HANDCOCK
02476 884548
john.handcock@citroen.com

KATIE READ
02476 884570
katie.read@citroen.com

MICHAEL ARNOLD
02476 884580
michael.arnold@citroen.com

CRAIG MORROW
02476 884261
craig.morrow@mpsa.com

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The Citroën brand:

Citroën harnesses creative flair and technology to enhance well-being. Since 1919 Citroën has made a major contribution to putting cars within reach of the general public, providing practical and purposeful answers to the questions arising in each era. Citroën cars today place a premium on design, comfort and useful technology. With 10,000 customer contact points and presence in over 90 countries, Citroën sold 1.2 million vehicles worldwide in 2015. The brand has also amassed eight manufacturers’ titles in the WRC and two Manufacturers’ FIA World Championship titles from the 2014 and 2015 WTCC seasons.