I took the behemoth piece of plastic under the front bumper off when I stubbied my front bumper. I'm assuming this is some sort of air dam, but what is its purpose, and more importantly, should I reattach it? Sorry for the noob question.

 

It's main purposes are to reduce drag, and to lower the air pressure in the engine bay. Lowering the air pressure in the engine bay allows more air to flow through the radiator.

These effects are subtle, so you may not see much of a difference with it off. It's most effective at highway speeds.

 

I stubbied my bumper too a few weeks ago, took the air dam off, and noticed a drop in mpg and a lot of hood flutter. I cut those "wings" off the ends of the dam so it was about the same size as the stubby and put it back on. I also velcro'd my hood latches. Together, these eliminated the hood flutter and restored some but not all of my previous MPG. (I used to get ~315 miles per tank on my JKU, now get ~305).

 

Ha! I noticed the hood flutter too! Ok, I thought my eyes were playing tricks on me. Would a front skid plate essentially do the same thing as the air dam while actually providing protection down there? Till then, I guess I'll trim it up and put it back on. Thanks guys!

 

Yes.

 

I assume a front skid would do the same, but in my limited research I haven't found one I like. If you go that direction, please post what you do.

There are some threads out there about using velcro or wire ties to strengthen the hood latches, but I didn't book mark them. You probably can find with a search. Basically, buy 2-sided velcro straps from WalMart and cut them to wrap tightly on the rubber insert in the hood latch in the closed position. You'll have to open them to feed them through, but secure them when its latched. Hood flutter gone.

 

I have thousands of miles on my JK, with and without the air dam. It absolutely, positively does not eliminate hood dance. There have been hundreds of folks who have attested to this on JK-Forum over the past 3-1/2 years. You're kidding yourself if you think otherwise.

 

If you really want to fix the hood dance, search on "hood dance zip-ties" or "hood dance daystar".

 

I took off the spring off that pushes the hood up so u can unlatch it. Make it a little harder to raise the hood up but no more hood flutter on the hwy

 

Mine is "loose" toward the back. Is that the way it is (or has to be)? Does anyone notice it flapping? I have some noises that could be it at moderate speeds.