[lunarhighway]

i intent to fit some small dams in front of the wheels of my vectra. it's got a pretty sweet 0.29Cd but there's room for improvement.
I'm trying to better understand why exactly these little dams are installed on production cars and how they function aerodynamically so i could trancelate that to my speciffic situation rather then just copy an existing design... of course these might have resulted from trial and error wind tunnel tests, but still some info might be extrapolated from the increasing number of existing designs. BMW for example seems to have the bigges ones i've see so far, but almost all their cars also have relative short overhangs before the wheels.

Ford seems to use a split design on the new focus and mondeo models with a straight section in front of the wheels and a second backwards angled part in front of the suspention sepparated by a slit (wich i guess is to allow cooling air to the breaks and perhaps to allow flexing when an obstacle is encountered).


my vectra already has small dams in front of the wheels at the bumper edge, but nothing directly in front of the wheels. In fact the inner wheelwell pannels end about 5cm above the lowest part of the bumper... extending these below this line would make very normal looking "wheel dams" as they exist today.

i'm wondering what dimentions i might aim for an if break cooling would have to be accounted for?


any insight on the matter would be appreaciated!