chuckdanny wrote:I can hazard a guess. If there is a y250/bargeboard vortex located on the undercut then the flow crosses the step spanwise in a manner that shed another streamwise vortex in the step(low pressure) that reduce stagnation pressure hence drag of the reartire plus enhance sealing of the top of the floor and reduce tire wake, 3 in one better than shampoo!
They've always had that and no one else does. Another thing I noticed is that they've always had a different type of CF layup in that area than other teams who have a big checkered board pattern CF layup for their floor. I am guessing its really a difference in CF layup that causes them to have a sandwich floor with something in between the top of the floor and top of the diffuser (bottom of the floor).