Video.................wind tunnel done right - not small scale.
How Effective is Your Aero? - Wind Tunnel Testing a Nissan 350Z
<iframe width="560" height="315" src="https://www.youtube.com/embed/Pgpawejpi6o" frameborder="0" allowfullscreen></iframe>
Because in Canada, you have to test it in the cold.
They can make it snow in there - WOW!