Chrysler 300M Enthusiasts Club
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LH Interior Modification Discussions

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 #379880  by LUNAT1C
 July 18th, 2019, 10:35 am
As I fill my shopping cart and spit-shine my credit card for the items needed to replace my evaporator, we've decided that while the dash is out it would be a good idea to also install sound deadening material on the firewall. I'm also going to re-route some added wires (speaker wires)... basically take advantage of the fact the dash will be out for the first time in over 17 years.

Naturally, as with all things, this will snowball into removing the seats and hard trim and carpet so I can deaden the entire floor.

The obvious first item will be to expose the entire floor and firewall and applying deadener to the flat portions of the sheetmetal. The deadener I'll be using will likely be SecondSkin Damplifier or Damplifier Pro. Dynamat is too expensive, and products like FatMat should NEVER be used south of the border (asphalt-based, outgassing in warm climates will be atrocious).

I've never had my entire carpet out, only lifted it up in a few places to run wires for my audio system. If I remember right, Chrysler laid down some type of sound-blocking material to the 300M. Can anyone tell me how extensive that material is? I've seen it near the firewall and I believe it stops right at the rear seat cushion leading edge, however I don't know if it covers the whole area beneath the console, front seats, and all four floorboards, and completely covers the firewall.

Obviously that must come out to properly apply the Damplifier Pro. However, SecondSkin also sells a Mass-Loaded Vinyl (which I believe is a similar material to what is in the car now) called Luxury Liner (and Luxury Liner Pro). Now would be the time to apply it if I was going to, however I am uncertain if it would even be necessary if the factory material is more or less the same and has good coverage.

Can anyone answer that question? Or have a picture of the cabin with the carpet freshly removed to see how much of it there is? I'd need it on hand on the day of the work and would rather not order more than is necessary.

My current thought is all I will need is the Damplifier Pro applied to the sheetmetal and nothing more, if that factory MLV is good enough. But there might also be opportunities to add Luxury Liner to any gaps.

Under no circumstances am I under the impression that doing this will turn a 17 year old Chrysler into a modern Rolls Royce, but reducing some road noise and vibrations would be nice and doing so with the dash out is best.
 #379884  by StealthM
 July 18th, 2019, 12:38 pm
Hey Robert. If my mind serves right the factory sound detinater covers about 80 percent of the floor boards. Its easily removed with a propane torch and scraper. After wards use some lacquer thinner to remove the residue. There is the heavy rubber matting that is attached to the firewall. That should pull right out... hope this helps.
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 #379886  by LUNAT1C
 July 18th, 2019, 12:52 pm
The stuff that's stuck to the sheet metal will be staying in place. No reason to remove it so long as the Damplifier sticks to it. The rubber matting, which I believe is a somewhat stiff vinyl with foam attached, is what I'm wondering about, how much coverage it provides. I'm not sure if anyone else has added a Mass-Loaded Vinyl to their car, whether it was added on top, or in place of the existing vinyl/foam material and what benefit there was in either scenario. I'd rather not waste the money on something not needed, or forego it and find out it would have been a good benefit.
 #379904  by StealthM
 July 19th, 2019, 12:19 am
Ok got ya. The rubber mat that your referring to is just sits down by your feet and goes up the firewall. It keeps the heat from the engine bay out of the cabin. You might get a little more protection by placing the dynamat under it but not much. I would focus on the floor boards and the doors. Hope this helps.
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