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GP Week : Issue 167
RALLY >>> TECH Inside R5 The final link in the FIA’s programme for rationalising the international rally car categories is now clear. Martin Holmes quizzes Karl-Heinz Goldstein on Group R5 The R5 class (formerly called R4T) is a turbo four-wheel-drive category aimed at providing a more budget friendly alternative for Super 2000 which, with the introduction of the 1.6 turbo version S2000s, has now become no cheaper than World Rally cars. The formula becomes effective on January 1, 2013. R5 cars are ultimately intended to serve as the sport’s second level formula, and rules have recently been approved by the World Motor Sport Council. Group R5 rally cars, like the two types of S2000 cars, are to be based on mass-produced cars already homologated within Group A rules (which means production runs of 2,500 examples in 12 months) and run with a minimum weight of 1200kg, like the current S2000. The FIA official delegated to the work of developing this formula is Karl-Heinz Goldstein, a former WRC engineer for various teams, who explained how this will come about: “It is intended as a lower level and more affordable version of Super 2000. R5 uses many of the principles behind S2000, notably the opportunity to convert an existing two-wheel-drive car into four-wheel-drive, but it can also be based on a production car that is already four-wheel-drive. “The engine must be a 1.6 turbocharged four-cylinder engine, not necessarily with direct injection. This can be either an already turbocharged engine from within the range of the manufacturer or a normally aspirated engine with an approved turbocharger added, but it must not be a Global engine design. “Maximum compression ratio is 10.5:1. The basic engine can be enlarged or reduced in capacity as required.” (Curiously the maximum engine size in R5, unlike world rally cars, is not 1600cc but 1620cc). “We don’t know the maximum possible power output of these engines as we haven’t seen a prototype engine, yet. The engines must have a 32mm turbo restrictor and a boost pressure limit of 2.5 bar as written in the rules, but with a proviso that there is freedom to change either if appropriate later on. There is no limit for maximum revs, as this is self limiting” . It is possible to use your own production turbocharger or you can change it to a FIA controlled one. The transmission must be a controlled design, using a five-speed gearbox (six-speed in S2000) with mechanical limited slip type differentials front and rear with limits on their use – for example with no negative pre-load facility. For the suspension, only McPherson type struts and shock absorbing systems can be used. Cost savings are planned for the suspension: “For example the S2000 uprights are often of welded construction, which are more expensive than those with machined construction. This means the R5 uprights are inherently heavier than the S2000 uprights but there will not be so many options to homologate. They have to be interchangeable front to rear, the suspension control arms as well.” Modifications for the bodywork can be made to allow fitting of the four- wheel-drive transmission in the same way as S2000, and additional openings are allowed in the bumper with extra air ducts for specific purposes. Maximum width of the cars is 1820mm, like the latest S2000 cars. Caps on costs of R5 are still being considered: “People were not so happy with a cost cap idea, but we still have it in the rules. When you talk with the people interested in R5, manufacturers and so on, they are all aware that you have to build an affordable car. People cannot invest so much money in rally cars. I have spoken with engineers who used to have other ideas but they have changed their thinking to cost effectiveness, which is good.” There have been no specific problems in the development of the R5 regulations: “Engineers are now asking how to interpret the various rules. We say how we interpret the rules. There are on-going questions all the time. “Recently the FIA has had to formulate policies on things like daylight lamps. For 2013 the wording has changed to be a little clearer for example, like when you switch on your headlights the daylights are going off. Some people wanted to remove the daylights to have more cooling for the shock absorbers, but that wasn’t allowed. If you take away your daylight lamps out, you must put an original part in.” As from the start of 2013, R5 cars will run in Class 2 alongside 2-litre S2000, 1.6 turbo S2000 and R4 cars: “Even with these changes, when you talk to the engineers who are designing these cars at the moment, they believe the car will be competitive in the class. There is no current plan to stop the use of the existing S2000 (2-litre or 1.6 turbo). Originally this was the idea but not now. The S2000 cars will run and run until the R5 has naturally taken over, certainly at least till 2015. The same with N4 cars. I think the policy is to let the existing cars continue even longer, to let them run until they die for themselves. There is no plan to cut them out.” Peugeot are expected to be the first manufacturer to produce an R5 design, based on the 208, with a similar car to be produced by Citroen, developed by the same engineering team, intended to follow shortly after wards. They say they expect to have their first car ready this northern autumn: “We are not pushing to know when the car is ready. It looks like all their existing queries have been resolved; they know now what to do. I think Peugeot is the furthest ahead, the leader at the moment.” The other manufacturer currently in active consultations with the FIA on R5 design is Skoda, but Ford have also admitted they are actively studying the opportunities for an R5 car at this time. Karl-Heinz Goldstein 35 GPWEEK.com // PARTNERS: