I cannot let Michael Cotton’s comments on the fuel consumption formula in Group C in his piece ‘Controversy in East Midlands’ (MS Oct.90) pass unnoticed.
When the formula was decided on, I was part of FISA’s Technical Committee and I may be accused of being biased, because I was really the man who boxed it through, against considerable resistance from most manufacturers involved or to be involved, except Porsche and Mercedes. Help came only from Committee President Curt Schild whom I had managed to convince and, if I remember well Committee members Eberhard Morr from Germany and Nigel Eason Gibson from Great Britain. Once the principle was accepted, which was the most important thing, the amount of the original fuel allocation was set at a much too high level 60 litres/100km because otherwise several manufacturers refused to endorse it. It was later reduced to 51 litres which, I feel, was still too high. Both Schild and myself, aware that most Cosworth DFV and DFL engined cars use less than 30 litres per 100km at Le Mans, thought that an allocation of 30 or 35 l/100km would have been more realistic.
One thing I want to stress is that the plan to adopt a fuel consumption formula did not originate from any consideration of fuel shortage, but rather from the fact that it is the only non-arbitrary way to give atmospheric and forced induction, as well as any other type of engine, equal chances. In contrast to a capacity limit formula, as will be used again from next year on, which imperatively requires the use of specific racing engines running at 13,000rpm and maybe more, a fuel consumption formula can be met with basically production engines because the high mechanical losses associated with very high rpm are detrimental to specific fuel consumption. From 1982 on, all major Group C races have been won with basically production engines, whether they come from Porsche, Jaguar or MercedesBenz.
When the formula was being discussed, rather than limiting the fuel allocation for the entire race, it was envisaged to use a fuel flow restrictor, but this was finally rejected because of possible reliability and accuracy problems. We also envisaged the possibility of an air flow restrictor, as advocated by Michael Cotton, but this was rejected on two grounds: a) the public easily understands the reason for limiting the fuel consumption, but limiting the consumption of air, which is free for all, is difficult for the layman to understand. (I believe Joe Lowrey put forward this possible solution, for F1 racing, years ago. ED).
b) though limiting the air flow automatically limits the quantity of fuel going with it, it does not promote fuel efficiency. An air formula contains no incentive to undertake all the developments made under the fuel consumption formula to improve the fuel efficiency, which were also undertaken in Formula One when the fuel tank capacity rule was introduced.
I maintain that the fuel consumption formula was a very interesting one and this is confirmed by all the manufacturers who took part in Group C events. It brought with it many useful developments which have since been adopted in production cars and will be in the near future. It also was a remarkable development exercise from which production engines have benefited and will benefit in the future, especially those on which the racing engines were based.
As to the sporting side and the problem of drivers having to drive on an economy basis or cars running out of fuel in sight of the finishing line, there is a very simple solution which I have often advocated: take a 1000km race and limit the fuel allowance to the first 500 kilometres only and make the consumption free for the remaining half of the race, making sure that on turbocharged cars, the wastegate setting cannot be altered. Nobody will be foolish enough to risk running out of fuel before the first 500km are covered, and if a car had to be driven carefully to reach half distance, the second half of the race will give it a good chance to catch up with the others. This would often result in exciting finishes while retaining the fuel consumption principle and the useful developments it encourages.
Whatever the future of Group C, which adequate promotion could make more popular, my opinion is that it is wrong to set the same technical targets in Formula One and Group C which now almost double up since future Group C races will be only marginally longer than Formula One Grands Prix.
Thank God we still have Le Mans, but the exclusion of turbo and supercharged engines which are to be found in many standard production cars all over the world, is a major error.