Coefficient of Drag
From Citroen SM Wiki
- The SM was reported at launch by Citroen to have a Cd of 0.25. Very extensive wind tunnel work was done on the car, uniquely for it's period. Amongst other things, airflow under the bonnet was tested in the wind tunnel.
- It was revised some years later to 0.339, which is the commonly accepted number.
- Note that this a great number even by todays standards.