My understanding of SPlitters is they come out horizontally from the car and not only help prevent air going under the car they help a bit with front downforce as the air coming down from the dam pushes down on it prior to going around the back.
This force has to come from somewhere though and that will be your engine so as usual in aero you need to make the decision whther it is worth the power loss for the downward force benefit.
rH+
Rev, I was a semi involved spectator on a race team up here that went racing with IMSA in the GTS1 category in the mid '90s (only a few race events, never the full schedule), they were allowed a splitter of a certain maximum dimmension (I forget how much, but not a whole lot).
In researching what was best, the member of the team in charge of that came to the conclusion that the drag penalty of a splitter would be difficult to measure so long as you kept is short enough (or made it stiff enough) so that it wouldn't need brace rods to the bumper.
Put another way, the 4 - 6 brace rods had several orders of magnitude more drag than the splitter (I don't recall it being very thick).
Of course at some point I'm sure you reach the ever popular "point of diminishing returns".
As I recall, there was a limit in the rules as to how far that lower surface could extend aft past he air dam too.
I have no idea where that gentleman was getting his information, and I have lost touch with him so I can't ask him.
All I know is the car went alot better than most people expected a car to do, that came from here.
(can't do that if doesn't stick in the corners
)
