Hi Aero....,
How about this one:
http://inter.action.free.fr/images/a...t-aerodyne.jpg
The main link to this sight gives a very interesting road vehicle aerodyamics section. Thank you Google for the autotranslation feature!
Check out
http://inter.action.free.fr/ Then hit the "Aero Lab" link, and follow by hitting the "Aerodyamics of Road Vehicles" link.