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  1. #1

    Default Where to put sound deadening mats

    I got these

    and I want to put them in my doors of my 84 T-Top. Where should they be placed for the best results?
    1. Inside the door on the side farthest away from the interior/closest to the road
    2. Just on the inside of the pull off door panel?
    Last edited by 84-tTop; 10-05-2018 at 05:49 PM.

  2. #2


    That is likely nearly impossible to answer beyond a simple opinion with nothing to back it up. If you've ever seen a 2015 and up Mustang without interior in it, it probably has 1/5 the square inches of sound deadener a 1985 Mustang did. But the places it is in is weird. And it's in little lines, not SHEETS like dynamat or whatever. Computers have somehow calculated where to cancel this and cancel that noise. I am aware the 2015 weighs 1,200 more than a 1985 but I mean the sound deadening must not weigh a 1/10 as much. And you know how much quieter the new car is. They actually intentionally plumb noise IN the car these days. Craziness. You need a friend in engineering school who could CAD scan a Fox and compute where and how much sound deadening to use, LOL

  3. #3
    FEP Power Member
    Join Date
    Nov 2007
    San Mateo, CA


    They are listed as boom mats. That means they are for removing noise from large panels. This would be places such as the inner side of tne door skins, bottom side of the roof and floor panels. Not so much on reinforced panels.

    I have no experience with using these.
    Fox Body/3rd Gen MCA Gold Card Judge
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  4. #4
    Moderator wraithracing's Avatar
    Join Date
    Jun 2010
    Grand Junction, CO/RR TX


    I would recommend install the mat on the exterior door skin, obviously inside the door shell. This will absorb as much road noise before it gets inside the cabin. You will be limited in what you can install as the crash bar is in the middle of the door. What I do is cut the mat down into workable sizes and install above and below the crash bar. I do the same installing the mat inside the rear quarter panels on the exterior sheet metal below the rear quarter window and the area above and behind the rear wheels. I also recommend installing mats on the roof sheet metal. This really stiffens up the large roof sheet metal and still helps a bit even with sunroof or T-tops. Lining the floor sheet metal under the carpet is another area that is highly recommended, even up the firewall sheet metal if you are tearing the car down that far, otherwise the floor will help.

    Bottom line is there is very little sound deadening in the average Fox, the later model Aero cars did receive a bit more, although still nothing compared to the new vehicles. You can also cover the inner door sheet metal completely if you want to maximize your sound deadening, but not a necessity. Good Luck!

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  5. #5


    Here's how I did my 86'. Covered the floor tub from the firewall to rear seat in butyl mat, then covered it in closed cell foam. Also added some butyl mat to the outer and inner door skins, then covered the back of the door panel with closed cell foam. A lot of people recommend covering the door itself in CCF, I don't like that route due to compromise in the ability to access the inside of the door without destroying the sound deadening. Hence the door panel route.


    1986 Mustang GT 5spd
    1998 Explorer Limited 5.0AWD (Wife's Ride)
    1999 Ranger Ex-Cab 3.0 5spd (My Winter Beater)

  6. #6


    How thick did you go on the material?

  7. #7


    Only one layer of each, butyl mat is .060 IIRC. The CCF is about the .125 thick. Made a big difference in road noise, cost about $150 and added only 15-18lbs.

    1986 Mustang GT 5spd
    1998 Explorer Limited 5.0AWD (Wife's Ride)
    1999 Ranger Ex-Cab 3.0 5spd (My Winter Beater)

  8. #8


    Looks good. Will have to add that to my to do list.

  9. #9


    Just to be the other end of the spectrum from Two86Five's results...

    Material I used was 50mils instead of 60. Only did the floor board in my Fairmont, but similar coverage. Did not do any CCF.

    I was not impressed by the results. So point is...if you don't go as far as he did, go further than I did.

    I do have a few sheets left over, I may try doing the door skins too. That will probably help.

  10. #10


    I have mixed my materials, but I used the DEI Boom Mat on the floor, lower part of the front panel, the rear quarters, and the roof skin. My computer stopped loading pictures to the FEP site for some reason, but I have it all documented on my YouTube channel. I had a foam barrier kit from LMR for the 87-93 doors (Scott Drake makes it) that I added a couple weeks ago. It fits with the earlier doors, but I had to cut out the manual crank window knob area and fit it around the clips a little. All of it makes a difference, but I don't have measurements of before vs. after.

  11. #11


    I went inside the door.... most excellent upgrade

  12. #12
    FEP Senior Member 83gt351w's Avatar
    Join Date
    Nov 2014
    Grand Rapids, Mi


    I went with the “peel and seal” from Lowe’s. Cost me about 75 bucks to cover the entire floor and cargo area. Works really well. I couldn’t tell you if it would work on vertical surfaces or not.

  13. #13


    here's a new one..... not meaning to offend anyone but rather share a good LOL...


  14. #14

    1986 Mustang GT 5spd
    1998 Explorer Limited 5.0AWD (Wife's Ride)
    1999 Ranger Ex-Cab 3.0 5spd (My Winter Beater)

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