air dam material

[Katmandu]

[cfg83]

garys_1k -

Originally Posted by garys_1k

Black coroplast. It bends right back even after a good whack. Some people use lawn edging, it's forgiving to a smack, too.

I was thinking the same, especially the lawn edging.

Also, I was thinking that you could back it with spongy foam to act as a spring. It would be light-weight and would allow the coroplast to compress/bend up and bounce back after hitting a speed bump and other urban predators of low-profile air dams. If the foam is integral to the air dam support structure, it would need to be "rigid" enough to withstand highway "wind" speeds (i.e. 60 MPH).

CarloSW2

[justpassntime]

I had seen some black lawn edging at Home Depot that had a thicker wall than most. It was a professional grade. It would have stood up great for this use, but when I went back to get it they didn't have it. All they had was the thin stuff that I would stay away from for this project.

[HondaNut]

I replaced the lower front bumper lip of my '93 Prelude with 6" of 1/4" thick neoprene rubber. It is held in place with two full width sections of 1" aluminum angle stock cut and bent to perfectly match the shape of the factory lip. The rubber is held onto the angle stock via 1/4" stainless steel hex-head bolts. Ground clearance is 1". This was just added to my car so I will report the impact on gas mileage after my next tank.

[wagonman76]

Ive had mine on for almost 2 weeks now. Ive scraped it several times in gravel and it didnt do anything to it except make it dirty. Today I scraped on this one steep transition in pavement that my travel trailer bottoms out on all time. It bent it a little, didnt kink it at all. When I got home I straightened it with my fingers and besides a little chipped paint it still looks just fine. Not bad for free. I should hit it less and less as Iearn which places Ive gotta watch out for.

[geoff]

Originally Posted by justpassntime

I had seen some black lawn edging at Home Depot that had a thicker wall than most. It was a professional grade. It would have stood up great for this use, but when I went back to get it they didn't have it. All they had was the thin stuff that I would stay away from for this project.

I belive that is the stuff that I got. They had it in 10' rolls. I cut it to fit and fixed it to the car with about 45 zipties thru holes I put in the underside of the bumper and the lawn edging. I then got one of those aluminum threaded rods and put it in the hollow loop on the bottom end of the edging, and used it to let me bend the lip to match the U shape for the bumper. Works well. I didnt have a drop in mpg, but also no gain (numbers are right where they always were) but I also do mostly low speed city driving (stop/go, about 45mph average).

i will post some pictures later.

[geoff]

the fatter pat at the bottom is actualy hollow, so I put one of those threaded aluminum rods in it and bent it to the shape I wanted, has held up well for the last few months/1000 miles.

I want to fiberglass over the center grill in the upper parts of the picture in the middle of the headlights), as it doesnt let that much air in and may help with overall airflow over the car.

[justpassntime]

Looks good. My Accord actually has a place for this to mount and with holes for the anchor nuts too. Aerodynamically speaking you would need to be traveling faster than 45 mph to see any noticeable gains. How clean is the underside of your car? Possibly a belly pan or filler panels may help some, but again at higher speeds. Most of my driving is highway, I would say 90%.

[cfg83]

geoff -

Originally Posted by geoff

...

the fatter pat at the bottom is actualy hollow, so I put one of those threaded aluminum rods in it and bent it to the shape I wanted, has held up well for the last few months/1000 miles.

I want to fiberglass over the center grill in the upper parts of the picture in the middle of the headlights), as it doesnt let that much air in and may help with overall airflow over the car.

It looks great, but I am not sure what you mean by "aluminum threaded rod". Do you mean for garage shelving or ?!?!?!?

CarloSW2

[geoff]

Originally Posted by cfg83

geoff -

It looks great, but I am not sure what you mean by "aluminum threaded rod". Do you mean for garage shelving or ?!?!?!?

CarloSW2

Exactly, it comes in different lengths, easy to cut with a hacksaw and also easy to bend while being lightweight. I chose it over just a regular rod because I figured the threading on it would help it "bite" into the platic lip and keep from sliping out of place. Along with the fact that it bends in on the edges and I sealed the ends off with silicone its been good, its just there to help it hold its shape in the wind.

Originally Posted by justpassntime

Looks good. My Accord actually has a place for this to mount and with holes for the anchor nuts too. Aerodynamically speaking you would need to be traveling faster than 45 mph to see any noticeable gains. How clean is the underside of your car? Possibly a belly pan or filler panels may help some, but again at higher speeds. Most of my driving is highway, I would say 90%.

Yeah, I do mostly city driving, I wasnt looking to get a huge gain out of it, and for the total cost invested (about $25-30) along with an hours work I was happy just to not loose any MPG. I havent seen any measurable gain or loss with it over the last 3 tanks of gas since I put it on (about 1000 miles and 2.5 months). I do almost completly city driving, only occasionaly going over 50mph. Ive heard that aerodynamics really only come into play with more modern cars above 55-60mph.

My office will be moving at the end of the year, and my 6 mile each way commute will be turning into 25 miles each way, with about 20 miles each way being highway, so I hope that things dont change that much adding an extra 10-20mph to my cruise speed (about 65mph from my now 45-50mph)

As for an undertray, the car has 3 different peices that run from under the radiator back to the mid point of the engine bay. I plan to get some of that corrugated plastic to help tie those 3 peices together, and carry the undertray further back, closer to the firewall.