Doesn't the location of that downforce play a big role too? I mean, putting out at the very trailing edge of the car is obviously more effective (for oversteer) than putting it on the roof. Did your calculations take into account the location?

 

First and foremost, these are really mickey-mouse ways of looking at it!!!

The cornering speed stuff, I looked at the car as a point mass. The car obviously isn't a point mass. But it serves the point of putting into proportion the magniture of downforce that we're talking about. The total amount of lateral force the tyres can give is pretty much the total reaction force multiplied by the coefficient of friction and increasing that reaction force increases the available lateral force but if we're taking about 60lbs or so, it's very slight.

For the balance, i was looking at the car's longitudinal reaction force distribution between front and rear and trying to give some indication to the original question of whether the wing at the rear affects front/rear balance - which it does not appear to do so. This IMO the most important role played by the (longitudinal) location of the wing.

I don't think the location of the wing affects the over/understeer in the way that it will act to reduce or increase the yaw angle regardless of where in wing is in relation to the centre of rotation of the car. I mean, if the wing was a vetical surface or a parachute then yes. Since the wing does not cause all that much drag (I hope), that shouldn't be a significant effect. Second order perhaps as the wing will cause some drag but not all the significant, I think.

The reason I think F1 cars are so dependent on front/rear wing balance for their under/oversteer is that they generate heaps and heaps more downforce that we can imagine. If they can make more than 1g additonal force on the front, then the front will grip a whole lot more and considering the front wing's location and the magnitude of the force, it probably lifts the rear a little too and that probably significantly alter front/rear available traction and centre of reaction force thus under/oversteer behaviour. Besides, there is also the airflow to worry about. You can have your front wing working real well but it will perhaps ruin the effectiveness/efficiency of the rear wing. I mean, if they can make enough downforce to stick the car to the ceiling that's like more than doubling the load on the wheels compared to static loads. If they have all that downforce to play with it's extremely possible that the car will work totally differently at high/low speeds. (and the guys who drive them are gods).

Going back to the front/rear change of balance on the evo arising from the wing, the WRC evo has the 'rear' wing just behind the rear wind shield, practically above the rear wheels. The intention is perhaps to avoid the downforce generated here 'lifting' the front end.... I guess... oh crap, another long post...

 

^^^ Too technical for me