15 days through the desert, on hard tracks and through soft sand, temperatures between freezing and over 40 degrees centigrade: The Dakar Rallye that will start in Lisbon on 5 January and will end in Senegal on 20 January, after 15 legs covering a total distance of 9,273 kilometres, is one of the toughest tests in motorsport.
Not only for the four Volkswagen factory driver/co-driver pairings, Carlos Sainz/Michel Périn (Spain/France), Giniel de Villiers/Dirk von Zitzewitz (South Africa/Germany), Mark Miller/Ralph Pitchford (USA/South Africa) as well as Dieter Depping/Timo Gottschalk (Germany/Germany), but, above all, for their competition vehicle, the Volkswagen Race Touareg 2.
To meet the rally’s tough demands, the Volkswagen factory team has subjected the 280-hp TDI diesel prototype that won the Cross-Country Rally World Cup in November with Carlos Sainz and Michel Périn to further optimisations in an intensive development and testing programme as well as having adapted the prototype to the changes in the "Dakar” regulations.
Intensive, detailed work for optimum performance
"While preparing for the 2008 Dakar Rally we concentrated on detailed optimisations of the Volkswagen Race Touareg 2,” explains Volkswagen Motorsport Director Kris Nissen. "For this reason, intensive tests with endurance runs took priority over the participation in selected competitions.”
Preparations for the 2008 Dakar Rally started as soon as they arrived at the finish of the "Dakar” in January 2007. "The last ‘Dakar’ showed that our speed is very good. After all, ten of 14 legs went to us. Now the objective was to optimise numerous details,” says Eduard Weidl, Technical Director of Volkswagen Motorsport. "We embarked on a so-called clean-up process during which we reviewed and improved about 400 items. From rerouting individual cables to installing new parts, we performed a lot of highly detailed work.”
Hence attention to detail instead of achieving major evolutions was the motto of preparing for the 2008 Dakar Rally. "An important aspect was to make the job in the cockpit easier for the drivers and co-drivers,” explains Kris Nissen. "We were now able to implement the things that used to have a lower priority.” For example, air conditioning can now be used on particularly hot stages of the rally, as better sealing of the vehicle hardly allows the intrusion of dust any more. In addition to ergonomics and comfort, the Race Touareg’s performance was fine-tuned as well. "We worked on the rear suspension kinematics and improved the distribution of weight yet again. This enabled us to achieve progress in terms of handling as well. The Race Touareg’s handling is now even more neutral than before,” summarises Eduard Weidl.
Rule changes require modifications of gearbox and air restrictor
For the 2008 "Dakar”, the Technical Regulations were changed: rally prototypes like the Race Touareg may now only be fitted with a five-speed gearbox instead of the six-speed units previously permitted. This posed an additional challenge to the Volkswagen engineers as the load is now distributed to fewer gear wheels and the steps between the gears are bigger. "We managed to develop a transmission with the same durability. After the first tests the drivers even felt the new gearbox was more pleasant, as they do not have to shift gears as frequently,” explains Kris Nissen. "However, the new gearbox reduces the top speed by about five kph, but this affects our competitors as well.”
The Volkswagen Race Touareg 2 is powered by an innovative 2.5-litre TDI turbo diesel engine. "This powerplant offers a number of advantages for use in cross-country rally racing,” comments Donatus Wichelhaus, Head of Engine Development at Volkswagen Motorspoort. "The engine develops very good torque, which is particularly positive on sand. Due to its low fuel consumption a diesel-powered vehicle can start to a longer leg with less fuel, the weight advantage compared to a car with a petrol engine can amount to as much as 200 kilograms.”
The current regulations prescribe a reduction of the air restrictor from 39 to 38 millimetres. "Reducing the size of the air restrictor was not an easy task for our engine department, but we came up with a good solution,” says Kris Nissen. "The total number of the optimisations we performed on the entire vehicle should almost completely offset the restrictions resulting from the regulations. At the 2008 ‘Dakar’ we shouldn’t be notably slower than last year.”
Successful tests and competitions
As early as in August the development work for the 2008 Dakar Rally was finished: During a 6,000-kilometre endurance run in June a whole "Dakar” distance was covered, while on another 4,000 kilometres at Volkswagen’s test track in Ehra the team simulated the driving on liaison stages. In September the Volkswagen Race Touareg proved its reliability yet again on 6,000 trouble-free kilometres in Tunisia. "After this run we just performed some brief maintenance on the car and then fielded it in the Morocco Rally,” says Eduard Weidl. Giniel de Villiers and Dirk von Zitzewitz finished the rally in the vehicle that had more than one "Dakar” distance under its belt with a highly impressive result: victory.
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