Any ideas for an airdam?
 

What would be an example of a good airdam for a Geo Prizm? The lower engine bay has a sort of fairing but the car is dirty underneath. Would adding a 1" or 2" airdam make a difference?

i have been thinking lately about air dams
 

they reduce the amount of air going under your car (which is a 'dirty' place) but I also think they create a higher pressure in front of the lower bumper. What if we made V-shaped air dams. they would have a point at the very front edge of the bumper and wedge off to either side and stop at the outside edge of the wheels. it might be better or it may have more drag than regular air dam because of friction with the iar rubbing on it. i don't know, just a thought. let me know what you think.

IsaacCarlson -

+1 idea. I don't know if it will work, but I'd like to hear what the aero-experts have to say.

CarloSW2

I was hoping to do something to improve the air flow. I know that if I lowered the car I could reduce some of the air flow and improve my cd/reduce drag. I would be guessing as to whether the "V" would be better. My thought was to add 1-2" of rubber or plastic to the chin of the bumper which would simulate lowering the car with a $400 suspension kit. The frontal area would increase slightly but the dirty underside would gain from the reduced air flow. Side skirts at 1-2" would be planned also. I don't have the time or tools required to do a belly pan which sounds like it would be best.

A fairly popluar method is the to use some Garden Edging from Home Depot. $12 buys enough for two cars and it is extremely durable. I used it on my car. Did the HD lip, mud flap removal and grill block and it was all good for around 3mpg. Because the HD stuff is so cheap, it make for easy expirementation. If it doesn't work, then your out $12 and you can make it happen tonight, vs. waiting and planning and dreaming...

http://ecomodder.com/forum/attachmen...1&d=1246670328

I agree on the lawn edging. I got a bunch of it in roadside piles during spring cleanup (some new stuff too), but $12 still isn't bad. Very durable for when you bottom out on steep driveway transitions or potholes or anything else. Am thinking about replacing the aluminum airdam on the Celebrity with this too.

Wagonman76,

Did you notice an improvement with the airdam?

I noticed about a 2 mpg improvement with the Celebrity after adding the airdam, and a similar loss when I took it off for awhile. Hard to say with the wagon, I haven't driven it much since adding the airdam. But since it is almost the same car and both undercarriages are the same (very dirty), I would think it should give a similar improvement with all else equal. I hardly drive it now, but will be driving it full time when winter starts.

That's a great idea I was thinking of using some conveyor belt. But I like this a lot better you don't have to trim it, and it's a lot lighter. I am doing the front end and this would work well. That is a very good MPG gain percentage wise. I will build it up before I put it on so it will wrap the front wheels.

Go to the Home Depot and by one length of vinyl gutter (the good architectural kind, not the cheaper "U" kind, it's still only about $4). Cut it lengthwise so you are left with an "L" shape. The back part of the gutter becomes the air dam and an inch or so of the bottom of the gutter becomes the forward-facing "L" mounting tab. Use the short L-tab part to attach it to the car with screws, velcro, or rivets. If you make a few straight cuts in the L part in strategic places the airdam part will curve nicely where it needs to (see my pics). The air dam is about two inches deep - just about the perfect height for my car. Any lower and it would be a pain at curbs and entrance dips.

I did this with my Volvo, attached it with industrial velcro and double-sided tape, and it looks great - almost factory. It can be painted if you use a vinyl paint.

Wow,
I like these ideas. Now just where do I put it? On the very bottom of the bumper or farther back? Mounting points like on the volvo are easy while on the Geo farther back (better IMHO) would be difficult.

Here is what I am working with:
http://i37.photobucket.com/albums/e8...k/IMG_0903.jpg
http://i37.photobucket.com/albums/e8...k/IMG_0898.jpg
http://i37.photobucket.com/albums/e8...k/IMG_0895.jpg
http://i37.photobucket.com/albums/e8...k/IMG_0896.jpg
http://i37.photobucket.com/albums/e8...k/IMG_0907.jpg

Are vortex generators good for shapes like my red car above?
http://i37.photobucket.com/albums/e8...0906G_CL_1.jpg

Your mounting points look almost identical to the Volvo so if you go for the PVC gutter material it would fit right along the bottom lip of the front bumber cover. The short section of the inverted L faces forward. Your second picture shows a perfect mounting area across the entire front of the car, and it even curves back toward the tires at the sides . Almost exactly the same as on my Volvo. I bet it will look great. You will have to cut away some of the L where those 3 center projections are, but I had to cut away some plastic where my fog lamps were mounted. It takes a bit of trial and error fitting, but the gutter material is very easy to modify with a small hand saw.

Just don't cut it too short by mistake. Cut it too long and then trim it shorter when you fit it. (don't ask how I know this). In my final version I ended up leaving it six inches too long and then bending three inches of it 90 degrees inward at each end to form two vertical mounting tabs that fit against the wheel well.

Also, if I had to do mine over I would make the horizontal forward-facing part of the L longer. Mine is about an inch but I would make it 2 inches and trim where needed. Basically the L part is one long mounting tab, and a two-inch tab is easier to attach to the car. Sorry about having no pictures but my camera is broken.

Your Geo sits lower than my AWD Volvo, so watch out for those curbs.

fairdinkumfrankies -

I vote for instarx' mod with the bigger mounting tab :

What's nice is that if it works for you, you could also use it for side skirts.

CarloSW2

I went to the auto wrecking yard and scrouged my air dam from an chevy pick 4WD. Actually enjoyed the hell out of myself.

Slanting the front dam down and back?
 

Would there be a benefit to the front dam slanting downward and under the car instead of it being flat (vertical)? Would a belly pan be needed to really aid in this at all? I am trying to think through my front-end mod. Wondering if the flat (vertical) dam routes the air out and around the vehicle or if it also forces the air lower? I might mock something up with tape\newspaper\cardboard just to see how it looks as a shape. Posting a pick might aid in discussion.

Or do i really want to slope FORWARD? Sloping back would increase lift under the car?

drilled and slotted rotors huh? cover up your rims man...nt
 

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Isaac,

I have been a user of cross-drilled rotors for years now. I used them because they never seem to warp under non-racing conditions. We first put them on a Taurus wagon that had a rotor warping problem (driving conditions were stop and go) and it solved it. Now I buy them for all of my main drivers. My wife will get a set when my new job starts. Only about $80 vs. $40 for stock. I was hoping to find some aero light weight wheels for a nicer car. That would look more hip, this one is a faithful beater. I also posted the photo because someone commented in another thread that they had a braking problem that was the result of hypermiling and for the post that had a concern over cooling w/full covers (pizza pan mod). I do have wheel covers on the car now and no one can see these babies. My car inspection guy loved it. His words "on a Geo??!". I told him it was for longevity. Thanks for noticing LOL!

I was wondering about the slant. IMHO it would seem that a rearward slant would be better than a forward one. The flat might be a middle of the road option but the easiest to pull off.

I do like the under body fairing but don't know how to make one that would survive a New England Winter. I have dragged the frame over a many a snow bank. Flexible airdam and side skirts are a must.

Wow. Those actually look really good! XD (Better on the Volvo!)

I'm actually going to do that myself!

Try an alunimun reinforced belly pan a'la someone on this site whose name I don't currently recall. Search "belly pan build" and you might find it.

About the slant: A rearward-leaning air dam would force air downwards, resulting in lift. Not good.

A forward-leaning air dam will force air upwards, result in downforce. Good.

For every action, there is an equal and opposite reaction. Push air up, you go down. Push air down, you go up.

With a flat air dam, some air would be pushed down, if the bumper above the dam sticks out farther than the dam itself, because air flowing upwards would be stopped by the bumper. More air would flow to the sides than anything, though.