A few questions about mods
 

First, does anyone ever make front wheel skirts, why or why not? When making wheel skirts does anyone ever use hinges to be able to lift the skirt up to get the tire off if needed? I know about air dams, but has anyone put air dams on the sides of the car? Finally, does anyone know what is the minimum recommended ground clearance? Sorry for all the questions, hope I can get some of them answered.

Welcome to the site. I'd like to encourage you to head over to the introduction forum and tell us a little about yourself.

Here are my answers to your questions:

Front wheel skirts are trickier because your wheels have to turn and skirts get in the way of that.

Yes, people have used hinges in their skirt designs.

Basjoos has side skirts on his car.

go to the home page, scroll down to the thread entitled "Aerocivic - how to drop your Cd from .34 to .17". Plenty of pictures.

Front wheel skirts.

why you would make them: they help
why you wouldn't: they're trickier (see also: doax's post)

side air dam? you mean wheel skirt?

ground clearance: 6"? if you want to be able to go over speed bumps. I've looked for a standard speed bump height before, but i haven't found one. maybe someone else has had better luck

*edit* I really suggest looking at the aerocivic for design questions. If it doesn't have it, it's probably addressed it.
*edit*

See also: DIY Rubber Front Wheel Skirts on a Dihatsu Mira

Other than basjoos and the Mira, I don't think anybody else here has done it, though I'm going to be looking at front skirts for my car later this summer.

EDIT: correction - Phil also has front skirts on his Toyota truck. See http://ecomodder.com/forum/showthrea...8976#post12727

ive been thinking about getting a set of trailer fenders and extending them to cover everything except the bottom 3 or 4 inches of the tire. It would be attached to the spindle so it moves with the wheel.

You should be able to get a very tight fit and really minimize some turbulence, plus it would look awesome. To take it off to change a tire you should be able to jack up the car and unbolt it, my tires drop @ least 6 inches when i jack my car up.http://www.northerntool.com/images/p...s/12640_lg.gif

what do you guys think?

Vince-HX: It depends on what you're trying to do. You still won't be able to "seal" the gap around the tire to smooth the flow past the wheel opening as your guard will be hugging the tire. It will, however, reduce losses associated with the boundary layer drag on the rotating tire and should keep your tires cooler (that's why big rigs use these things). It will eliminate much of the need for pizza-pan hubcaps.

saunders: There are vehicles with "side skirts" that are like air dams on the side of your car. They work well in vehicles that have a low front air dam to keep air from flowing under the car from the sides. I think this is a lot of the reason that long-wheelbase luxury vehicles have pretty good drag coefficients as a lot of them are straight-sided pretty low to the ground (BMW 7-series).

I'm pretty sure that 6" should be more than enough ground clearance on a car. My motorcycle sits 5.3" off the ground dry. With fuel and me on it, it should probably be at least half and inch to an inch lower. I don't know if that clearance would work well for cars or not.

As to the side skirts,Check out basjoos' Civic.As to ground clearance,the Society Of Automotive Engineer Standard Practices dictates that a fully-loaded passenger vehicle have a 16-degree "approach" angle,as measured from the front tire bottom projecting up and forwards to clear the underside of the nose.The "break-over"angle in between the wheels, project up to meet each other at a 10-degrees where they intersect the rocker panel.Behind the rear tire,the "departure"angle is also 10-degrees to clear under the rear bumper.If you drive very carefully,or leave or enter driveways obliquely,you can cheat a bit,without scrubbing the car to pieces on the road.Active suspension is tops,although a little pricey.