[Cd]

Originally Posted by 3-Wheeler

Hi basslover911,



As basjoos has mentioned earlier in this post, you definitely do NOT want to lower the car in anticipation of getting higher MPG's, because they have a strong chance of actually dropping from this mod.

Take a look at the PAC Car II pictures that are on-line. Notice how this car is actually 'raised' from the ground.

Raising the car actually improves the slipperyness of any vehicle, discounting the raised exposure of the tires to the frontal area of the vehicle.

Typically, the best Cd of a 'floating' vehicle high above the ground is about .04 and when this same vehicle is lowered within inches of the ground, it's best Cd now becomes .08 or so.

This is due to the ground effect, which changes how easy the air goes around the bottom side of our ideal shape.

So in summary, except for exposing more tire area in the frontal view, you can decrease your effective Cd by 'raising' the vehicle. Of course this always causes other side effects, such as decreasing vehicle dynamic stability in handling, due to the CG now being higher. There are always compromises to make!!

Hope this helps.

Jim.