Please excuse me if this has been discussed before. I am trying to figure out the big difference that gives the focus wagon a lower coefficient of drag. The focus is the same from the B-pillar forward, so all of the difference is in the back of the car. The roofline is the same height, and the wagon has equal or as little taper as the hatchback. I wonder if their measurement also included the roof rack.
The things that boggles my mind is that the rear end is slightly longer, but the primary difference is only the rear roofline and hatch. You could count the squared off ledge in the bumper cover as well. In theory, you could duplicate the shape of the wagon easily on the ZX3/ZX5 and drop .05+ off your cD... ?
Sedan:
cD: 0.31
Frontal Area(est): 21.97 sq.ft.
ZX3
cD: 0.36
Frontal Area(est): 21.97 sq.ft
Wagon:
cD: 0.30
Frontal Area(est): 22.24 sq.ft.