Grille block and test by the famous MetroMPG:
Testing grille blocking & wheel skirts: +5.7% improvement - MetroMPG.com
The graph is a good one to post at your site.
Ask them how well their cars would do with wings and an aviation engine strapped to it. It wouldn't fly. Too heavy, underpowered and not aero enough. That might get them to see things from a different perspective.
Show them a Porsche 911 without a grille. Hmm.. never thought of that did they?
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Vortex generators are old tech. My new and improved vortex alternators are unstoppable.
"It’s easy to explain how rockets work but explaining the aerodynamics of a wing takes a rocket scientist.
