Considering a low, flexible air dam
 

After 15 great years, my 2000 Honda Insight was totalled. :( Not that bad an impact - an older car is worth next-to-nothing so it's easy to get totalled.

I got a 2007 Prius, and it behaves differently, but that's for another thread.

Got several project for my Prius, including an air dam to improve the underside aerodynamics.

I'd like the air dam to come 2-3 inches of the pavement, and think it might be possible if the last few inches are flexible plastic that could give so the road does not chew it up fast. Anyone try this?

anyone?
 

MetroMPG reminded us that the Crisis Fighter Pinto of CAR and DRIVER,1974, had a very low airdam and it helped with their MPG.
Also,graduate engineer Feysal Ahmed's Masters Thesis research showed a drag reduction for a pickup with a 3" clearance airdam,although he recommended it only for racing applications because of the demands of driveway ramp clearance 'n such.
Some members have used rubber belting for low airdams and it seems pretty indestructable.
Give it a go and keep a good logbook to see if she 'shows' on the computer or at the pump.:)

I was thinking about putting one that low on Ron Burgundy myself before an armadillo took out part of Turtle's belly pan.

I don't know of any material that will give you the aero benefits you're looking for and also survive an armadillo hit with it hanging that low. But if you find it, I might still do one myself!

Here in central Florida we also have lots of gopher turtles, racoons, possums, the occasional cow in the road, etc . . . . lots of stuff to tear off all my hard work

I put a rubber conveyor belt air dam on my 2005 Toyota Tacoma. I use it offroad a lot and have drug it repeatedly without issue. See the link to by build thread below, note that I changed it a couple times throughout the build.

I love it for the handling increase.


http://ecomodder.com/forum/showthrea...tml#post453541

I haven't, but I've got 3 1/2" clearance to the tow hook and maybe 5" to the front valance. I'd drop it another 1 1/2" but there are 3 bump strips between the street and my carport.

The best one I've seen I can't find using site search, maybe someone else will recognize the description. It was a Metro/Civic-like vehicle with a conveyor-belt airdam down to 2-3", like you say, in front of the tires but was notched up maybe 2" in the center.

I think this would do two things. The extra clearance delays high-centering on gravel drives, etc.; and the center section didn't have the curvature of the ends to resist deforming so it's gets relieved for less pressure.

For some idea of the pressure involved look at this air dam:

http://ecomodder.com/forum/member-fr...6-bedammed.jpg

Look how thick the aluminum plate is, and the number of fasteners to hold it on the car. These Beetles don't run much above freeway speeds. :)

You might want to use something like spring steel fingers or something on the upper backside.

I used 3/8" ripstop conveyor belt for my air dam.

The stuff is a bear to fabricate and not at all cheap, but it is flat indestructible. I've had it on my truck for over five years and and it is in good shape. A little rubber conditioner and it looks like new.

After much experimentation I found that the right height for the air dam is about 7" above grade in front of the wheels and 9" above grade in the center. this height keeps it out of parking curbs.

I tried my air dam as low as 3" above grade but at that height it dragged the ground every time I hit the brakes. No major damage (just ground the botto a little, but it annoyed the hell out of me.

I'd recommend the stuff.

Thanks for suggesting the central notch.

If it was easy to fabricate, it wouldn't be as indestructible. What did you use to cut the ends and the notch?

If you want super cheap, lawn edging from one of the big box home centers.

If you want wookie-tested/wookie-tough, conveyor belting like Big Dave said. It sounds like a specialty product but baler belting is essentially the same thing, and you can get that at Tractor Supply in widths up to 10" by 15 feet. $100 out the door, not bad considering what you're getting.

I cut mine with a sharp utility knife following a ruler/straightedge. It cuts pretty good but you need a sharp blade. I got a 7" by 15' roll at TSC, it was less than $100, probably about $50 or so. I also ordered another piece of conveyor belt off ebay (which I haven't used yet), they have every size imaginable and their prices are better then TSC.

airdam & belting
 

This photo is from a Master's Thesis done by a US NAVY officer,sent to me by 'bondo'.He also used the conveyor belting,and as you can see,went very 'low' with it.
http://i1271.photobucket.com/albums/...itled-15_1.jpg

How do you go lower than the wheel rims and not get pulled over by the cops?

http://67.media.tumblr.com/7c0e279fb...sapto1_400.jpg
http://67.media.tumblr.com/c89dbf90d...sapto1_400.jpg
Guns, Oil, & Dirt

cops
 

I've no idea.Especially in California.

There's so much stuff on the highway I'd hate to create even less clearance than I have now. My '15 Mazda3 measures about 7 inches clearance under the front bumper valance, and about 5.5 inches clearance under the streamlining panel hanging beneath the engine.

I very well may not be able to clear an armadillo laying flat in the road.

I hate to drive at night because by the time I see an object on the Interstate it's too late to move over, so straddling is about the only option left, which is a very poor one given 5.5 inches of clearance. It seems to me that to give my car even less clearance is strongly challenging the laws of diminishing returns.

So far, I haven't hit anything hard enough to cause any known damage to my Mazda, but road gators coming off an 18-wheeler caused $5K damage to my wife's Explorer, which is much higher off the ground than my Mazda.

I'm already averaging 43mpg with the Mazda. The risk of increasing the damage potential by lowering the car even more is not worth it to me. I guess it would be a different story if I drove only in town where one has time to stop or maneuver to keep from hitting something, but then the efficiency gained by a lower car in town is probably negligible anyway.

I've got 3.5" to the tow hook and 5" to the crossmember. It would be less but for bump strips and the curbs they always seem to have getting in and out of gas stations. I admire the young folks with their stanced this and air-bagged that.

The problem with highway speeds is ground strikes on bridges. Even a 1.5" discontinuity running across the traffic lanes will throw the wheels enough to bottom out.

Edit: last time I took the Wheatland Ferry the river was low, so I dragged pretty badly going on. The operator rammed the other bank at speed to force the ferry up the ramp to make it easier for me departure. :thumbup:

Look for a lip option. I'm sure there is something out there to get you a little closer, then look into something flexible if you want to go lower. I just added a lip to the front of my civic I pull off an accord and brought myself to 6inches of clearance. So when I drop it I'll be at about four inches which is plenty low enough.

M-B goin' with 4.5"
 

In an article about future Mercedes-Benz products,they mentioned that with their active air suspension,they'll go as low as 4.5-inch ground clearance for drag reduction.