Cd of 2011/2012 Jetta TDI

[Cd]

Originally Posted by mspropst

Hi,

Also, how to calculate changes to the Cd


Thanks.

Try doing a coast down test like this :

Measure the drag coefficient of your car

[Pendragon]

Originally Posted by Cd

The Flow Illustrator tool is nice, but will not show real world results like the vortexes that show up around the sides of the car, or other problem areas like under the car.

As I recall it, VW had a Golf TDI show car which was shown at the Geneva show a couple of years ago. It was supposed to test reaction for a production version, but I do not think it made it any farther than that.

They lowered the car somewhat (1 1/2 - 2 inches ?), installed low rolling resistance tires and a new front facia from a GTI (?).

I do not know if anyone has a mathematical model to determine the benefits of reducing the amount of air getting under the car and/or modifying the air flow because of it by simply lowering the car with a suspension kit.