Quieting down the inside of my cobra

[MrSwa]

I recently went on a quest to quiet down my 03 on the inside. I absolutely love the way the car sounds, but having to yell to communicate has gotten a little old. To attempt to get the best of both worlds, I went looking for a way to quiet just the inside of the car. The obvious choice was to add more sound deadening. Dynamat was out due to cost. From here I went to mcmaster.com and looked for sound deadening material. I found something I though would work, part number 5692T61 and ordered 22ft^2 of it (approx enough to do the trunk with a little left over). For comparisons sake, 20ft^2 of dynamat xtreme is $190 and 22ft^2 of this stuff was $43. Today I went out and cut a few pieces to cover the trunk.

I removed everything from the trunk space (including the side carpeting), and put down a few pieces. I ended up not putting any in the actual spare tire hole (got hot and decided to try out what I had done). I put the trunk back together and just got back from a drive. While it's not as quiet as a stock car, it is noticeably quieter. Mostly muffled the exhaust noise coming into the cabin. Road noise is still very apparent. I got too excited and forgot to take pictures (sorry).

I probably have 8ft^2 left so my next step will be to cover the spare tire hole, and the wheel well tops in the trunk. If I'm still not happy and I decide to get frisky, I might try and take up some of the carpet and install it underneath (this prob won't be for a while due to funds and time).

Overall, I would have liked for it to have gotten quieter, but this is a good start. I'm going to try and do the spare tire hole and the wheel wells tomorrow, so I should be able to get picture then. For the record, I tried to use a decibel meter on my iPhone to measure the difference, but it just bounced around a lot. Didn't take any video before either so our of luck on that end as well.

 

[Evan5469]

Another easy spot to do is under the rear seat if you don't want to go through the hassle of taking out your entire interior. It just pops out with 2 push pins in the center of each where the cushion meets the carpet. If you reach under there you can feel them. Just push in and the seat bottom should lift right up. Hope this helps. :thumbsup:

 

[greengt88]

U can try a product called fat mat. I used that in my fox. I think I got 2 50ft. Rolls for $100. It was on ebay. I also used mass backed carpet that had a rubberized coating on the back. It really quieted it down. I have no a/c in ther either and it helped with the temps. I did my entire roof, floor up to the firwall and the entire hatch wheel wells and tire well. Huge difference. Just get a large hard rubber roller it will make life way easier. It took me 10hrs. To scrape out all the fac. Sound deadner and lay down the new stuff. U will also need a box cutter with a lot of xtra blades.

 

[Jefe]

Foil faced? Skin or uncoated?

Definitely want to do this soon. What parts under the car can you put this material on to quiet road noise? IRS subframe?

 

[greengt88]

U may want to try a product called POR 15…from the eastwood company. Its a type of undercoating. Its similar to rhino liner in strength. U could do the underside of the spare tire well

 

[greengt88]

Doing the floor will make the most difference. The fatmat I used is foil on one side and looks and smells like tar. Same as dynamat. It takes awhile for the smell to go away. And it seems best to leave it sit out in the hot sun afterwards to cure it. Once its on and cured good luck getting it off. I did 2 layers around the trans tunnel. Really helped with the heat.

 

[MrSwa]

Thanks for all the tips. I will look into the undercoating. Can't decide if I am bold enough to remove the carpet. Installed coilovers today so I didn't get a chance to put it under the rear seat. Hopefully I'll get a chance to do it tomorrow. We'll see.

 

[MrSwa]

Foil faced? Skin or uncoated?

Definitely want to do this soon. What parts under the car can you put this material on to quiet road noise? IRS subframe?

What I got did not have any coating. I think this will be fine for under the carpet in the trunk. It was just adhesive backed. I cut out a piece that I wanted, remove the backing little by little, and stuck it down as I went. I wish it was foil coated, but I can't see paying a crap ton more for it.

For the underside I would assume some kind of spray on undercoating would work better. Side note: the undercoating from walmart is not very thick at all. I just used it for my wife's civic's wheel wells and it needed several coats.

 

[black 10th vert]

Doing the floor will make the most difference. The fatmat I used is foil on one side and looks and smells like tar. Same as dynamat. It takes awhile for the smell to go away. And it seems best to leave it sit out in the hot sun afterwards to cure it. Once its on and cured good luck getting it off. I did 2 layers around the trans tunnel. Really helped with the heat.

This something that would definitely piss me off, having the tar smell inside the car. That is why I'm probably stuck going with the more expensive butyl rubber versions. As much as I hate to spend so much on sound deadeners, I guess you get what you pay for in this case...

 

[bwahl602]

im gonna skip the sound deadener mat bc the stuff is really heavy. Im gonna use the spray on stuff that second skin audio sells. Its called Spectrum.. its a paint like sound deadener. Should be lighter and easy to apply once the interior is removed and i mask the car off..

im topping that with there luxury liner pro

bill