dukesauto

how about some recent pics instead of 5 years old

eogel

Here are my 2 wheel to wheel race cars. Red car has a homemade plywood splitter covered with fiberglass. It sits 3-3 ½” off of the ground to allow for suspension compression when at speed. This car has stock suspension, but the heaviest springs front and rear.

The green & white car is relatively new to me and has not been corner weighted or had ride height set, so splitter height is not where it should be. This car has coilovers, so I expect the splitter height to be lower than the red car when set up due to a stiffer suspension.

See avatar.

mfain

Don't forget to think "dynamically". It really doesn't make much difference how high (or low) the splitter is at low speeds. I have a high travel suspension with bump stops on the shocks. I set the stops to put the splitter just touching the ground at high speed (max aero down force) and/or max braking with the maximum roll I expect for the lateral g-loads. On rebound, as in acceleration off the corner, the splitter ends up about 4 inches above the track. Look at the videos of the new C7 Z06 at Nurburgring and you will see (and hear) the splitter scrape under heavy cornering loads. Some guys on the C7 Z06 forum are really whining about how high the car sits and how "un-cool" that looks, but if you look at the travel under racing conditions, it has to be that way to utilize the spring and sway bar rates GM has selected. I personally think they need a little more roll stiffness in the front - the car appears to have an excessive roll angle and is really unloading the inside rear tire during hard cornering. Here is a picture of a factory-stock C7 Z51 at Nurburgring that will give you an idea of how much the suspension travels -- dynamics.