 The use of biofuels will also be allowed in the prototype categories, with petrol engines allowed to run 10% ethanol, and diesel teams allowed to use biodiesel.The GT1 and GT2 categories remained unchanged in the new rules.Prior to the Le Mans Test Day, Audi announced that they would be the first team to adapt their cars to use 10% biodiesel as allowed by the new rules, with partner Shell developing a biomass to liquid fuel.