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Sound Insulation

9944 Views 21 Replies 9 Participants Last post by  dtlee
I recently purchased a used '01 Insight and drove it up from Monterey, CA to Renton, WA. Two full days of freeway driving really shows how much this car needs some sound deadening. So I started looking into what others have done and posted about.

grebe and Mr. Salty have used Quietcoat's QuietCar liquid product and seem happy with the results. From Quietcoat advertising, the QuietCar seems very flexible in that it can be used as undercoating on the exterior or inside the car.

Rick (AZ) and BlueInsight1701 used .25" generic insulation mostly just laid out without glue except in the doors. This was fairly cheap and gave 4-5 dB noise reduction.

Rick Reece used Brown Bread, LComp, and foam with satisfying results. (I swear I read someone getting 8 dB reductions with this same type of install, maybe the yahoo forums)

After reading about all of this done last year, 2003, reading all of the propaganda from the marketing departments, and trying to get a sense of what is going to work well, I am leaning towards a combination of QuietCar to damp panel vibrations and generic .25" thick insulation material to absorb the sound that gets through.

Does anyone have updated information on their installs from last year? For the QuietCar installs, is the material still holding up? Has it flaked off or degraded in quality? Any regrets? Any odors resulting from installs that people are regretting now? Any changes to the insulation/damping materials installations since last year?

I plan to decide what path to take in April sometime and do the install in May along with my stereo system.

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Wow you've done your research, thankyou.

As far as the sound insulation in mine's been going so far so good. I have removed the piece under the rear carpet and the piece going up the wall behind the seats. They did almost nothing and I was scared that it might cause too much heat to the battery box durring the summer. I still have the piece in the rear well, and it's been staying put quite nicely. Again, I wanted it to be removable.

Clayton's (BlueInsigh1701) car has since departed, and he removed everything. In fact I still have 3 of the 4 under carpet pieces from his car in my garage. Whatever you end up doing, if you can please go to radio shack and buy a $30 sound level meter so we can get some before and after results. We were the only ones that did that to my knowledge.

I'm still convinced I have more sensative than average hearing, but quite honestly mine still leaves something to be desired, but really in comparison to normal cars it's on par with their road noise level. I know if a quieter tire was used it would make all the difference in the world, but it's a sacrafice I suppose.

Mine was done in a few steps, the two areas the made the largest difference were the doors and the rear well. As a general disclaimer here I will say again, any insulation you do can potentially cause things to get too hot and could result in warranty problems. This is why I really wanted removability on mine. Of course, I guess that might not be such an issue where you live. One other thing to consider, the material we used is pretty much what is used in every other car, but it seems if it gets wet that it won't easiliy dry so you might want to take this in to account. Phoenix doesn't see much rain.

Good luck, keep us posted.
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One thing I think I should mention, particularly reguarding the loose stuffing. On the bottom of the IMA box the alluminum has holes in it to aid in venting. The air is forced in through the vent behind the passenger seat, throught the box then out the bottom and back of the box. This is something you don't want to interupt. The carpet pad I used covers the floor all around it, but still lets air freely flow through this space. I have also lined my dead navi brain space as well.

As far as xcel's questions, have you looked underneath the carpet in your MDX? Every other vehicle I've seen partially torn apart has the same carpet pad type material underneath the carpet and sometimes attached to the back of panels. The only remnance of any insulation I've found in the Insight was under the rear carpet, and it is only a few small thin pieces of it. We did a little research before our insulation project and quiet cars had the carpet pad that was about a half inch thick.

As far as the doors, easy. Remove the door panels and apply the sound deadening material to the back of the plastic door panels. This way you never touch the plastic sheeting in the doors and it had good results for me. Actually, the doors probably were only second in improvment to the rear well. Quite honestly the floors had only a marginal effect, but I'm keeping the pad there.
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Yeah that sounds normal. Most of the insulation is down near the floor in the vehicles. You should be able to feel the insulation below the carpets. They will be cushy, not hard. I can't comment specifically for other Honda's/Acura's, but my moms Yukon has the plastic pieces that cover the rear wheel wells insulated on the back side with a similar carpet pad material. Anything further up than that would probably not make much if any difference.

This thread's got me starting to think some. I might go back and put a thicker pad (which I have a small roll of sitting in my garage) in the back well in the car and see what difference it makes.
Yes the cargo mat helps. I still need to get one one day. But it's still too noisy. You need something up against the outer panels to absorb the noise.

The dead navi brain space is where a shoe box sub woofer would go. In Japan you get a navigational system on the Insight, the computer for it goes in that dead space.

As far as behind the seat, I had a piece of insulation there for a little while underneath the carpet. I took it out back when I was having what I though was IMA problems of some sort (no brake lights, no brake signal turned out to be the problem), and it really made no difference so I left it out.

I think you'd be amazed how much of a difference just putting some sort of insulation in the rear well, under the carpet on the floor and in the door panels, which is all I have. Also, I guess I'll mention that new tires will also make all the difference in the world. If yours are getting old and weather cracked and near the tread wear indicators consider new ones. I wish I had taken before and after readings recently when mine were replaced. It sounds like a normal car inside again.
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