1975 Porsche 924
Aerodynamic development of the 924 began using one-fifth scale models that were tested in Paris Laboratoires Eiffel. The results gained from these tests were then applied to full-size prototype that was optimised in the Volkswagen wind tunnel.
With the headlights retracted, the Cd was 0.36. With headlights up, it increased to 0.38. Projected frontal area was 1.76m2, giving a CDA of 0.634m2 with the headlights down, and 0.669m2 with the lights raised.