Running underweight in F1

Jenson Button, San Marino GP 2005

Jenson Button, San Marino GP 2005 

 © The Cahier Archive

It took the FIA Stewards the best part of six hours to confirm that Jenson Button's BAR-Honda was legal after the San Marino Grand Prix. According to a statement the car was weighed after the race and was above the minimum weight limit but was subsequently drained of fuel and found to be underweight. The FIA rules state that a car must weigh "no less than 600kg at all times during the event". This is impossible to measure because the cars are racing and in the past there have often been suggestions that some teams may have been filling up the cars with extra fuel at the end of the races in order to ensure that the car is above the weight limit. This means that the cars can be run underweight if someone sets out to break the rules. However there are signs when ,for example, cars have short final stints but fairly long final stops. The fuel flow from the refuelling machines is known to be 12 litres per second but it is difficult to measure the amount of fuel going into a tank because the time that a car is at rest does not necessarily equate to the time during which the nozzle is on a car.

One can construct arguments in most races. In the case of San Marino, for example, one of the cars did three stints of 27 laps, 22 laps and 13 laps. At the first stop the car was stationary for 9.5secs. The second stop was for six seconds. From that one might calculate that the nozzle was on for eight seconds and thus the car took on 96 litres. Logically the car would have been empty at that point because drivers want to go as far as possible in their first stint. The fact that the car returned to the pits after 22 laps would mean that consumption was about 5.2 litres a lap. This being the case it might be considered odd that the final pit stop lasted for as long as six seconds and one could calculate that 72 litres were put into the car when only 62 were needed and that would suggest that there would be 10 left in the tank at the finish. As each litre weighs around 0.8kg, that could in theory mean that the car was underweight at various points during the race. The problem with such a theory is that unless one can monitor the nozzle time exactly one cannot know if someone is cheating because one or two seconds can make a huge difference.

Whatever the case, BAR successfully convinced the FIA that the problem was something other than fuel which is logical as big corporations such as Honda have nothing to gain by cheating because of the negative impact if they are caught. It is better to lose races than to be caught cheating.

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