Thanks everyone you've all been a great help. And you basically confirmed the inevitable that I was trying to avoid. Wind tunnel and field testing. Just trying to save design time. As usual behind schedule, but not over budget. Yet.
Is there a book(s), software or rule, that I can use to model air flow over / under a car body for the purpose of determining high and low pressure zones at different speeds. I'm investigating the placement of openings and type / style of opening for component cooling. Additionally any...