spray liner OVER sound matting (like Dynamat)

[Ryan Matthes]

Searched the web and haven't found any information on this more recent than early 2013 - most from the 2004 to 2007 timeframe, so putting the question out here…

I need to quite down the inside of my LJ. Did a 5 hour drive on back-roads / hills with my wife and 2 year old, and the exhaust noise is so loud, that it got to me (long after them). Still have the carpet inside, lined a TJ years ago and loved it. So - I want to see about putting in Dynamat and then Linexing over the top of it. Has anyone done this? I am looking for information on direct experience - not opinions for opinions sake. Thanks.

 

[kojackJKU]

I don't think it would work good. I could be wrong, but my brain is telling me that the dynamat will flex causing cracking.

 

[brianjwilson]

I'm curious too. I'm selling my jeep but had an idea about doing this before as well. I always figured if the spray in liner was flexible it might work okay.

 

[05nissanXterra]

Spray liners by nature are flexible, after all it's a rubber based material. The reason it doesn't seem flexible after you spray it is because of the material you apply it to. The dynamat will not move enough to cause the liner to come apart the hard part will be getting the spray liner to adhere to the foil backing of the dynamat.


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[Ryan Matthes]

Spray liners by nature are flexible, after all it's a rubber based material. The reason it doesn't seem flexible after you spray it is because of the material you apply it to. The dynamat will not move enough to cause the liner to come apart the hard part will be getting the spray liner to adhere to the foil backing of the dynamat.


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That is exactly what I was thinking too - how well will it adhere to the foil backing. In one thread from 2004, one guy left a small gap between the sheets to allow the spray liner to adhere directly to the metal substrate, and one other person actually perforated the foil backing to allow the spray liner to penetrate the foil backing. Neither of these had any long term follow up that I was able to find.

I ordered a 10" x 10" piece yesterday and am going to stick on it on a piece of 16ga sheet steel and then take it to a local Linex place to get a spray out sample - I plan to then "work this over" to see what occurs.

 

[05nissanXterra]

From working with spray liner in a previous profession, if you were to perforate the foil backing it would have a much better chance of adhering to it, the only problem is that the liner is so thick that I probably won't "settle" into the perforations instead just sit on top.
I think if the liner was sprayed thick enough like .25" or even a bit thicker that it wouldn't need to actually adhere to the dynamat, it could actually just sit on top like carpet. You'd just need to make sure that all the way around the edges it would have plenty to adhere to, so not to have it pull up.



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[kojackJKU]

that's what I meant when I said crack, I mean peel. no adhesion to the foil.

 

[brianjwilson]

Is the foil backing thick enough to scuff it up?

 

[MotoDave]

Another option would be a spray in sound damper, the one I'm familiar with is Lizard Skin. I believe you can spray on bedliner coating over top of it.

 

[Ryan Matthes]

Another option would be a spray in sound damper, the one I'm familiar with is Lizard Skin. I believe you can spray on bedliner coating over top of it.

Fantastic thought - that is an idea I had not thought of. Does anyone have any experience with Lizard Skin?

 

[05nissanXterra]

No experience with it... But sounds plausible.


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[CRolandLJ]

Seems like a stock muffler/exhaust set up would be cheaper and easier. Exhaust is the last thing I hear in my bone stock LJ, especially when i had a soft top. Wind noise, etc are the top noise makers and lining/dynamat obviously wont help that.

 

[Ryan Matthes]

Seems like a stock muffler/exhaust set up would be cheaper and easier. Exhaust is the last thing I hear in my bone stock LJ, especially when i had a soft top. Wind noise, etc are the top noise makers and lining/dynamat obviously wont help that.

I agree with you completely and am probably going to go that route - I love the throttle response from the Banks exhaust, but the drone at speeds got to me on this past trip. The wind noise really wasn't that bad, even with the gear on the roof. Trying to find a hard top as well, which is part of why I want to "deaden" the sound - not just the exhaust. Planning on taking the LJ on some long trips in the coming year.

 

[CRolandLJ]

The hard top makes a huge difference on long trips. I know a lot of people knock them for being difficult to take off or whatever but as soon as i bought a house with a garage I made the switch, thinking i'd keep my soft top as for the summer but ended up selling it after it hung on my wall for a year.

A) As a daily driver in Texas I find 4 day to week long stretches to take my hard top off with no rain in the forecast and leave it off for the whole time, I'm not taking it on and off constantly. I did this with my factory soft top as well.

B) With a garage and a hoist (my homemade hoist with eye hooks and ratchet straps was super cheap) i would argue it's just as fast to take off as my soft top PLUS there's no clutter flapping around in the back while you drive, its cleanly off.

 

[1stDeuce]

Speaking from an engineering perspective, I don't think you'll get much additional sound improvement from doing both... Unless you dynomat the WHOLE inside, including the inside of the soft top, you're just spending money, not solving your problems... I think adding bedliner alone to the inside might get rid of a small amount of noise generated by the floor and rear fenders, probably similar to what dynomat would do for the same. Unfortunately, 90% of the noise you perceive is likely coming in through the soft top, and there's not much of a fix for that. Honestly, the best bang for your buck is going to be finding a larger muffler that would be quieter.

When I built my Jeep, I went with a kit from Gibson, as they were a lot more civilized compared to what was offered for an LJ back in 2005, but I don't know how they compare to Banks. My jeep does have some lightly resonant engine speeds at low speed, but once I get to hwy speed, it's not bad at all. Might be you're just running it right at a resonant exhaust note. Does downshifting one gear make it any better?