https://www.langracing.com/bmw-race-...ir-dam-design/
https://nasaspeed.news/tech/aero/air...e-whole-point/
"An air dam can be one of those magic improvements, increasing downforce and reducing drag at the same time. It can also improve engine cooling by increasing the air flow rate through the radiator. An air dam reduces drag by reducing the rate of air flow under the car, which reduces drag caused by all of the protrusions and cavities under the car. Everything that you see under the car is a drag source, so hiding that mess behind an air dam is a simple way to reduce drag."