Quiet interior

[Noah96]

Looking at getting a cooper restorations floor mat and some dynamat. Would the dynamat under the floormat be too thick, has anyone ever done this?

[Sheepdip]

The "Dynamat" that I have seen is only about 3/16" +/- thick. My son put it in his 70 CST with no noticeable difference. It's a peel and stick with a wooden roller to promote better adhesion.

[Overdriven]

In my opinion (and experience), dynamat works best to stop vibrations and resonance. The best example I can give is imagine that tinny sound of rain on the roof of an old car, it kind of “pings” when it hits the roof skin. New cars you just hear a dull thud. This is because new cars have more structure in the roof, foam, adhesives and insulation supporting the roof skin so it can’t vibrate as much. Put dynamat on the inside of a roof skin on an old car and you’ll get similar results.

The floor, even in our trucks, has plenty of contours and support that it really doesn’t vibrate or resonate. You’ll get some sound deadening by putting dynamat on the floor but in my opinion it’s not really worth it if you have other insulation already. The automotive shows put dynamat on the floor because it’s an all out build, with a loud exhaust and crazy stereo that’ll turn the vehicle into a tuning fork if they didn’t. You’d be better served putting dynamat on the inside of the door skins, back wall of the cab and as far up the firewall as you can get. If you really want more, there is insulation that can then be glued on top of the dynamat to deaden the sound frequencies dynamat isn’t as effective against.

[nikwho]

It's not too thick, at all, in my opinion. With my old '67 Pontiac Tempest build I wanted the car to be as quiet as possible. I used a full kit of Raptor Liner on the bottom of the body/floor, and another full kit on the floor in the interior of the car. When I had the entire car pulled apart for paint, I also sprayed raptor liner on the inside of the firewall. Then, I laid DynaMat on much of the floor, the roof above the headliner, on the firewall, in the doors and inside the quarter panels. Then I put the padding on the firewall and a full carpet kit. It made a tremendous difference. In my '68 GMC I lined the floor with the aluminum coated water heater wrap that you can get at hardware stores and it seems to have nearly as much effect on sound as two kits of Raptor liner and a bunch of DynaMat. I'm still going to add DynaMat in select areas, under this layer, but this stuff works great! Blocks heat and sound very well. I also coated the back wall of the cab. The carpet holds it down nicely and it cuts out much of the drone from exhaust, too.

Nik