sknguy wrote:Just a note of interest, but wouldn't relying on the diffuser/groundeffects be more dangerous than relying on the rear wing for downforce. I should think that the wing would provide some safety features which the diffuser could not. Better braking and stability for an unstable chassis perhaps? Would this not be a correct asumption?
Not quite sure what you mean by dangerous. Though IMHO, the diffuser by itself without wings and only has the body surface for downward forces acting on the lower pressure area created by the diffuser. The diffuser would allow what small amount of forces to occur due to the removal of the "lift" forces that get created underneath (greater possibility of lift occuring without a diffuser).
It becomes a matter of balancing that with the setup of the car and any addition elements that could be added to the body, spoilers, air flaps etc.
The same is true of adding wings along with the diffuser, the diffuser adds more leverage of downforce to the package. Balancing the wings for stability becomes the object of focus.
In my opinion it's incorrect to say the diffuser generates or creates any downforce at all but rather increases the leverage of wing's (downforce) or any down ward forces created through spoilers, body panels, flaps etc. All of these have increased efficiency with a diffuser present. Personally I prefer to describe a diffuser as an anti-lift device.
Though some may argue that it's only semantics and that "down force" and "down ward forces" are the same thing, when looking at car balance and setup balance as a whole package, there are some very fundamental differences between the two in when considering stability.
A note about braking ability. A winged car has far greater braking ability than without wings even with a diffuser on either. The air drag (and slightly increased wing angle due to pitch) produced at the initial strike and beyond of the brakes being the difference. Diffusers offer no drag penalty that helps braking.