wvumtnbkr UltraDork
April 21, 2017 9:15 a.m.

I am trying to install an air dam on the front of my chumpcar. I do not want to make any silly mistakes. I have a couple of questions...

1) How close to the ground should it be?

2) Does it need to have anything behind it? In other words, I do not have a splitter on the car and the airdam will just hang down from the front of the car.

3) anybody have any tips and tricks or experience I can learn from to avoid common mistakes?

I plan to use "circle track roll plastic" to make the air dam. I was going to secure it to the plastic/rubber bumper of my RX7 with about 25 rivnuts (for easy removal). I was then going to brace the back of it with some aluminum angle iron strips that go to the stock bumper.

Any help is appreciated!

Thanks!

Rob R.

jimbbski Dork
April 21, 2017 9:26 a.m.

Depending on the suspension set up (How stiff are the springs?) and what you could hit/run over if you have an "off" during the race should determine the clearance from the bottom of the air dam and the pavement. I have used that same plastic and the only added bracing I used was a strip of that "angle iron" aluminum along the front edge of the air dam so it acts like a "mini" splitter.

wvumtnbkr UltraDork
April 21, 2017 9:32 a.m.
jimbbski wrote: Depending on the suspension set up (How stiff are the springs?) and what you could hit/run over if you have an "off" during the race should determine the clearance from the bottom of the air dam and the pavement. I have used that same plastic and the only added bracing I used was a strip of that "angle iron" aluminum along the front edge of the air dam so it acts like a "mini" splitter.

Cool! Thanks for the reply!

Does it matter if there is nothing behind the splitter? There will actually be a "pocket" between the stock bumper and the airdam. I was worried this will create drag or even lift if I don't "seal" the airdam to the bottom of the car.

like this:

That area between the blue and the red would be open on the bottom. The aluminum braces would be strategically placed to hold the shape of the airdam.

Is that "pocket" going to cause problems?

fanfoy Dork
April 21, 2017 9:38 a.m.

Aero wise, that pocket shouldn't cause any problems. But why not simply hang it from the bottom of the bumper?

wvumtnbkr UltraDork
April 21, 2017 9:40 a.m.
fanfoy wrote: Aero wise, that pocket shouldn't cause any problems. But why not simply hang it from the bottom of the bumper?

Not nearly as much structure...

DaveEstey PowerDork
April 21, 2017 9:44 a.m.

I would bridge the gap between the radiator opening and air dam. The rest of what you're thinking seems good to me.

iceracer UltimaDork
April 21, 2017 9:46 a.m.

lower your car to the bump stops. that will determine your ground clearance.

Be sure to allow venting to the brakes. Very important.

A friend didn't and cooked his front pads at a track day.

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