following detailed description fig1 shows a schematic perspective view of a side region of an engine compartment 9 with an air filter system 1 of one embodiment of the invention in this case the side region is substantially taken from a wheel housing 18 of a front wheel a dot dash line characterizes in fig1 the transition zone 11 between the engine compartment 9 with the laterally disposed wheel housing 18 as well as with a filter housing 5 which is to be disposed on the wheel housing 18 and an air intake region 10 in which an air intake opening 29 of a raw air duct 4 is disposed the cooler device 35 of the vehicle is disposed between engine compartment 9 and air intake region 10 in addition to the raw air duct 4 and the filter housing 5 an adapter 13 also pertains to the air filter system 1 this adapter being disposed in a bodywork opening 16 and having a first tubular attachment 19 with a first receiving opening 14 toward the air intake region 10 the first receiving opening 14 can receive one end 20 of the raw air duct 4 if the raw air.