Aerodynamic Aids - What a drag, What’s your drag? Options

[chris914]

Have you made changes to your 914 body or are you thinking of it?

Here are a number of computer models comparing different body modifications to the 914 and the effects that they have on the cars aerodynamic drag.

http://www.cassidy-online.com/porsche914/aerodynamic_aids

[Mugs914]

Just a few somewhat random thoughts to add to the discussion:

Sean is right, "wind resistance" is not linear. Aerodynamic forces (drag, lift, downforce, all of the above) function as a square of the speed. In other words, double the speed and aero forces quadruple.

When you are looking at a various race cars for examples of things to try, keep in mind that the wings on those things are very tightly restricted by the rule book. Even those humongous billboards on the A mod cars are restricted (If I remember correctly) in the overall area and number of elements. Most of time what you see on race cars are not the ultimate solutions to an aero problem, but the best solution they can come up with and still be within the rules.

I did a study once looking at low speed wings in an autocross application. I found that a 6'span, 1' chord wing with the proper airfoil and camber (Very similar to the wing Paul has built, by the way) could produce as much as 45 pounds of downforce at 30mph. Doesn't sound like much, but last time I looked they time autocross down to the thousandth of a second... A small advantage is still an advantage!

Very, very generally, downforce helps in the turns, drag reduction helps in the straights. Look at where you spend most of your time on the track and in most cases an increase in drag in exchange for more downforce is a good swap. The only place I know of where minimum drag wins races is at Bonneville... (IMG:style_emoticons/default/biggrin.gif)

Suit on; flame away...