Interesting thread.............
A wing to give downforce at relatively low speeds would need to be rather large. Seems to me you would create a aerodynamic imbalance in the car that while may help corner exit could in fact slow your lap times due other factors as a result of the imbalance.
Where is Richard Hudgins?
Seems to me you have done some good things already. Additional items I would think about. Get the air out of the wheel wells. You need to let the air out in a low pressure area, ideally where it will not further interrupt the laminar air flow over the body (little Cobra joke there
). Stop the air from coming under the car. Front dam (as wide as possible) and side skirts. Plug up that BIG opening in the front. I know you have ducks to the brakes, but do the body openings really need to be that large? Even a extruded type mess over the radiator,
oil and brake duct openings in the body should improve aerodynamics (I have heard 2-3 MPH on the top for this). Be SURE that the duct from leading to the coolers is sealed to the coolers and that the taper from the opening to the cooler is a gradual as you can make it (no more than about 15 degrees). No sharp edge on entry. It would be great to give this air some place to go. The 'Turd' was an attempt at this. Rear chin spoiler I am sure would help. Make it like the nascar boys do and play with height and angle.
The rear diffuser seems to be an interesting idea.
IF I ever get spare time I have daydreamed about a scale wind tunnel where I could play around with the aerodynamics of these cars. But, in the end, they are aero-bricks.
A manometer, some tape, yarn tufts, a video and still camera and a willing couple of friends with another vehicle can give you lots of valuable information.
Rick