OEM insulation in 1997 fzj80

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Does anyone know what the OEM material is on the 1997 80 series interior floor is that’s permanent adhered to the body pan and wheel wells - it approximately 1/4” (250 mil) thick ?

If so does anyone have an idea waht its properties are as a baseline for sound insulation and thermal proofing ?
 
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It's some sort of sprayed on asphalt based dampening material. Try a search using the terms Dry Ice as that's what people have used to freeze then remove the original material.

Some people have removed the original material before putting down the sheet type dampening material (Dynamat, Hushmat). Some put the new material right over the old. Some people report it doesn't make much of a difference (no improvement) either way. AFAIK no one on this forum has done a scientific study to show that new dampening material on the floor by itself is better than the original.

A few people have used the spray on/brush on liquid material to go over the old.

A few more people have installed new carpet with sound blocking backing which they report did help decrease noise. IMO that may be the easiest way to decrease road noise via the floor.

If you're looking for a quieter vehicle there are many options, but main IME
is to decrease the micro vibrations of the sheet metal by use of dampening sheets on the large flat sheet metal surfaces (inner door skins, quarter panels, ---) then install a thin closed cell foam sheet on the backside of all interior panels to block sound transmission into the cabin.

Also important to make sure your window and door rubbers (glass runs, weatherstrips) are in good shape, even the smallest air leak will allow road noise into the cabin.

A few people have pulled their headliner to install dampening sheets on the roof followed by new insulation.

And if you had a million dollars you could install thicker laminated glass all around if that is even available.

It's a big subject, do some searches on the forum and the nets.
 
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So for sound deadening do door panels first and test ?
For thermal insulation for both heating and cooling insulation . . . but especially for reducing heat in the summer,
what kind of thermal barrier should be used over the body pan metal and OEM (asphalt) material ?

The top floor cover on this solution is intended to be rubber and not the OEM carpet.
 
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especially for reducing heat in the summer,
what kind of thermal barrier should be used over the body pan metal and OEM (asphalt) material ?

To reduce the amount of radiant heat entering from the engine and transmission, you could add modern, reflective insulation on the outside of the body panels. You'd have to drop the transmission to do it, though, unless you've got some kind of technique I've never heard of. Maybe a trained raccoon with those creepy little hands, or something...

For heat reduction, you'd probably benefit far more from adding ceramic tint to your windows (including windshield) and painting your roof white. You could remove the old jute insulation from the roof and replace it with Thinsulate SMx00L.

IMO the biggest noise reduction payoffs, by far, are from adding mass loading to the doors, Thinsulate to the rear quarter panels and (if you're ambitious) doors, then mass loaded vinyl under the carpets with some kind of padding between the vinyl and the floor (Thinsulate, carpet underlayment, Noico foam, whatever).

After that, your primary noise source will probably be the sunroof and window/door seals. Plus, as an Oregonian, the non-deadened roof is obnoxious during winter rain. If that's an issue for you, mass loading the roof will help tremendously.
 
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Incidentally, another trick to reduce noise coming through the doors is to replace the plastic membrane with Dynamat/Noico/whatever. It's not the ideal solution, but it works pretty well. Similar to this (from some 4Runner forum):

sound_dead_41.jpg
 
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"You'd have to drop the transmission to do it, though, unless you've got some kind of technique I've never heard of. Maybe a trained raccoon with those creepy little hands, or something..."

I actually did something like this without dropping the transmission but have normal hands and am not a rocket raccoon. I pretty much completely covered the front of the floor (underside) starting from where the firewall curves downward and back to just behind the front seats. With the transmission in place. I ensured 100% coverage above the exhaust pipes and cats on the right side.

Having said that it is something I would not recommend and would never do again. I could get above the transmission by working on my back in the driveway on an unlifted 80 but it was an absolute sheit ton of work. Spent most of the time cleaning off the sheet metal using turpentine then a specific paint prep spray so as not to damage the paint. Then I applied hand cut sheets of Hushmat a little at a time. It's amazing how uneven the floor is that you don't realize it until you try to press on that type of aluminum backed material.

What I learned from it was the obvious when you think about it. Any sheet metal, even feet away from where you're sitting, that is not fully covered by the product (I used Hushmat Hoodliner) will progressively heat up and the steel will conduct that heat to the parts of the sheet metal floor that are covered.

So it did work to help deaden road noise and it did decrease some of the heat coming up from the cats in the passenger footwell by about 20 degrees but it did not completely eliminate all heat coming up from below.

Bottomline: the amount of effort just wasn't worth the payback. Easier to apply or install whatever product you're going to use on the floor (topside).

FWIW
 
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Thanks for the advice.
I’m a minimalist, which means I will likely spend and do as little as possible.
 

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