OK...this question is racing related but only heard discussed in NASCAR, mabe you can help me understand. On cooler days typically at superspeedways you hear of the crews taping off the grill. Obviously you can only do this in cool enough conditions or for small quantities of time such as qual. They say it creates more front downforce and reduces drag..........OK here we go. How do you INCREASE downforce and REDUCE drag. Seems unusual but mabe I'm missing a formula somewhere.

Thanks