Conceptual wrote:I think that it has more to do with the lower "mid-wing" supercharging the steeper diffusor profile.
The mid-wing forms a part of the diffuser if what I *read* is correct (I haven't seen any decent photos, so cannot *really* comment with conviction). The lower surface of the mid-wing will in effect become the upper surface - the suction surface - of the diffuser.
This increases the expansion area ratio from the floor to the diffuser exit, which results in the effects scotracer has done a very, very good job of explaining.
There are also effective areas (analogous to effective profiles) to consider, and more aggressive diffuser profiles will result in yet more gains. Until of course separation, but current F1 diffusers are a good way from that.