Please Trash my Cheap Air Dam Idea
 

My Dodge Ram's factory air dam doesn't go down far enough to prevent air from impacting the front suspension, or the other rough areas near the engine.

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For aero mods to be cost effective they must be inexpensive. What I'm thinking about is getting a second factory air dam, inverting it, and attaching it below the existing one.

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This should be fairly cheap, $50-$100. The extra 4" in depth should help aero, but shouldn't interfere with normal operation.

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Since there is a nice flat surface around the bottom of the existing air dam attaching the second, bottom to bottom, should be easy. Maybe 7 bolts.

Also the flat upper mating surface, what will be the bottom on the new one, should make it easy to fill that area with a sheet of 1/4 ply. Will be about 16" back from the from edge.

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Since I'm pretty new at this, and need to learn, please fire away. Tell me where I'm right, where I'm wrong, just plain nuts, and improvement ideas.

$50 for an air dam is WAY TOO MUCH! You would be much cheaper off to use landscape edging or something similar, which can often be had for under $2/ft.

clearance
 

Drive around to places you normally go,which require you to nose up over a raised curb/sidewalk in order to park.Measure your free space vertical clearance up to the existing airdam.
This will give you an idea if you're fixin' to shear off the lower dam or not.
It really sucks when that happens!

sounds good to me. you might need a way to brace it so the wind doesn't make it collapse backwards at speed.

Aerohead, raised curbs are a rarity to me. This is an advantage of living/working in smaller communities.

Bill, since the curve shape of the existing dam holds well at highway speeds, with the current mounting, I'm hoping it will do the same when doubled. Plus I'm going to do 1/4 ply mounted just above the bottom. This should keep the airflow away from the suspension, plus stiffen the structure.

Thanks for the input.

Well, nobody's called me a horse's rear yet, so maybe I'm onto something good.

I used some extra roofing sheet which is a flexible rubber about 3/16ths of an inch thick. I went down 4" to match the suspension components on my Dakota. I then helped support it with a little bit of sheet metal, but I really need to redesign that.

I did all that, along with Royal Purple Gear oil in the rear, and full synthetic change of the transmission... and then started going to a different job so i wasn't able to properly test a difference in economy. I don't think it was a huge difference though... sadly.

Also, instead of using 1/4" ply for your bellyban stuff, coro-plast, or the plastic cardboard stuff that signs are made of, would be a LOT better. Lighter and just as strong.

Also, think about a grill block. I plan on doing that next and see if it works any better since when the weather bumped up, I went from 14 to 17 mpg with no change other than getting a few extra tools out of the back.

I know everybody here really likes coroplast. But I've got some spare 1/4 (along with 3/8, 1/2, & 3/4) ply in the tool shed. So it's got the edge.

And it's a BIG no on grille block. I spent 10 grand and 3 months (don't ask!) getting this trucks motor replace a year ago. Water pump went bad and heat destroyed the motor. The 4.7 doesn't like heat. So anything that maybe possibly could someday interfere with cooling is out.

The reasons for using a factory air dam: 1) ease of install, no engineering required. 2) will look like a factory job, air splitter will be hidden.

If you've got it, use it. It's going to weigh a bit more than the plastic, but probably hold up a bit better if you make sure to put a good coat of paint on it to prevent water damage. Overall the extra weight probably won't make a dent in the MPG's as it's only a few pounds.

The reason Bill in Houston mentioned bracing it a bit more is because of the added wind load on the air dam. It may not be a problem, but the last thing you want is the existing dam cracking due to the pressure. A $2 bracket or two is far better than the $50-$100 air dam.

I have the 4.7, I"ll let you know how it does with a grill block.

X2

Cool idea if you can do it cheaply. It is amazing what those things catch on. I have cracked or broken several airdams over the years. Since you are starting with a high clearance vehicle, maybe you'll be OK.