A few years ago, I added side skirts to my Civic.
I removed them since they add several feet of frontal area to the car when hit by a crosswind. *
What kind of FE hit does a car get from increased
side frontal area ?
On a similar thought, what about boattails and the increase in frontal area that they produce ?
* Where I live ( the 'hill country' ) , there is a lot of wind that blows in from the sides of the car.
