glad we all agree on 7 degrees then!......I think we have differing opinions on how it all works, but the parcticalities of the design advice above still stand.
as your racing a 3 series beemer, the chances of using the rear wing to pull the air through the diffuser is zilch.......thats for LeMans, F3 and F1 cars........
I just dont understand that a diffuser is supposed to slow the air?......if so then why do people use the depression under the rear wing on LeMans F1 and F3 cars to "pull" the air through the diffuser.......a pull would indicate that faster is better
also looking at all diffusers from the birds eye view, why are they wider at the front/entry and narrower at the rear/exit.......an F1 front wing is a classic example......not wanting to argue, just curious thats all
I always remember Adrian Kidd pointing to his diffuser on his F4 car and saying the faster that air go's through that, the more down-force you generate.......from an aero perspective - that makes sense to me