The revised technical regulations for 2009, designed to cut downforce, specify a much smaller rear diffuser. Brawn, Toyota and Williams have interpreted the rules differently to their rivals and have adapted other areas of bodywork to effectively enlarge their diffusers.
Stewards at both the season-opening Australian Grand Prix and the second round in Malaysia declared the ‘double-decker designs, which use bodywork openings to feed them more air, legal. However, BMW Sauber, Ferrari, Red Bull and Renault have all appealed the stewards findings, questioning whether the diffusers adhere to the wording and spirit of the regulations.
Should the Court agree with them, it could in theory strip Brawn, Toyota and Williams of their points from Melbourne and Sepang, which would dramatically alter the face of the championship table. Alternatively, it could insist they change their diffusers for a more ‘conventional design.
If the Court deems the diffusers legal, then it will leave the other seven teams on the grid playing catch-up. Many have already begun development of similar diffuser designs - thought to be worth as much as half a second per lap - which, if required, could be introduced as early as the Bahrain Grand Prix later this month.
A decision is expected from the Court on Wednesday afternoon.