I`m done spending BIG money on my heap for now and am lookin at ways to make my dart a bit better at speed and wanted to hear/see what you guys have done. My first area was going to be be the rear valance area in which I was thnking about drilling some 1" holes across the back and inside where the support brace is to releave that area of air as it looks like it catches quite a bit. Then I was curious if you guys think air going THROUGH the car would help like; removing the plastic piece that bolts to the inner fenderwell behind the ft. tires and even drillin holes in the doors and door jam to release that pressure area..........almost Indy Car like along w/a ft. air pan. Am I off base here or is it simply back to the "Air needs to go around the car not under it" deal............thankxxx.........

I'd think your biggest gain would be to put some plastic behind the grill opening (I've already made templates for mine) You could also run a chin spolier this will keep the air from going under the car and bouncing all around. Not sure cutting holes in the rear valance will help much. I have always heard running w/ the vents open helps but I warn you, make sure they are clean and free of debries... leaves, pine needles, nut shells, dirt make a heck of mess at 100mph AMHIK.

Did the grill thing and slowed down but lookin back I had it recessed into the grill and not flush which caught too much air. The ft valance/damn is something to look into for sure also...........Don`t have vents anymore as I completely gutted the ducting and it`s blocked off anyhow below the window.

Your car already runs better than it should. How much more could you want out of that thing.

Well your hood scoop is facing the wrong direction for Aero...

Was waiting for that one...........

Mine really liked the front grill area all blocked off - other than engine temps. I removed the rear valance/roll pan on the back of mine because it looked like it would trap air under the bed - and it made zero difference at all. The jury is still out on whether my front air dam helped or hurt my mph - but it made it handle WAY better at speed.

Drag cars don't spend much time at high speed, but aero improvements would help above 60 or so. Air going through the car increases drag as opposed to air smoothly going around it. Getting the nose down and addressing airflow at the roof/windshield and under the car would be your biggest improvement; hard to do anything about the roof/windshield without cutting. Back in the AFX days, it was learned that a spoiler on the trunk lid brought MPH up. The Dart's concave rear window hurts aero. I remember a Car and Driver study on a Dodge B100 van where the biggest improvement was removing the mirrors.

Looking at your truck the grill block-off makes sense but on a brick of a dart it didn`t help in back to back same day tests........

Havn`t tried that..................

Maybe this is too fugly for you car but I put 2 small hinges on the lower rad support and some diamond plate and made a air valance but to push air to the radiator.
here is a clearer pic of it.

Have you see my car? Fugly............

Dom you could go this route http://magneticbrain.blogspot.com/2010/03/deception.html

I put a chin spoiler on mine and fiberglass between the bumper and lower valance so no air can enter. Didn't see any mph difference running on the throttle stop only added weight. When in Boise we took the spoiler off no change in mph put it back on same mph

just build a SB and get rid of that boat anchor up front, your not going fast enough to worry about aero

Get the car lower to the ground... cover the whole
bottom of the car with thin alum so you dont have drag
on all the junk under there... dont let the air get
under the car... side mirrors.. gone.... but being
your a street car you cant do most of the stuff that
will reduce drag... angle of the windshield is too
steep..... so basically you cant do much