From the 2007 GCR glossary, page 116: Engine Compartment - The loosely defined volume, nominally enclosed by panels on top and sides, which is the normal location of the engine in a car.
From the 2007 GCR, IT Category Specification 9.1.3.D.1.c:
...Air intake source shall be within the confines of the engine compartment or stock location...
At the NARRCOffs we impounded ITS cars to check air intakes. I saw a BMW 325 which piqued my interest, but I decided I was looking at shades of grey and chose not to write the car up.
The pertinent question is whether the engine compartment stops at the radiator and its mounts, or can be thought of as continuing on to the grill area. The GCR definition of Engine Compartment is unhelpful in this regard. Discuss.