66 Impala Sound Insulation - Impala Tech
Interiors Upholstery & Soft Trim

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post #1 of 10 (permalink) Old 04-20-2018, 02:55 PM Thread Starter
Join Date: Aug 2016
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66 Impala Sound Insulation

I am trying decide what type of sound insulation to use on my floors and doors of my convertible. Its seems the best product is Dynamat xtreme. However, I saw on a post the person used EX Cool for most of the floor with Dynamat around the shifter. I also saw on the internet people using FrostKing HVAC insulation because it is much cheaper with similar properties of Dynamat.

I would appreciate any advice on what I should use.

Thanks all,

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post #2 of 10 (permalink) Old 04-20-2018, 03:56 PM
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Any product that has an adhesive backing (and in homage to Red Green I have to mention duct tape will work as well) will act just like your hand touching a cymbal that has been struck. Your hand dampens the vibration silencing the sound. If the material has a shinny aluminum coating it will also reflect heat out of the cabin. As such the FrostKing HVAC insulation will work just as well as Dynamat.

I don't add insulation because I spend time to scrape filler puddy out of the sheet metal seams to lighten the car. I build full on race cars that have a tag and title to drive on the street, not a Pebble Beach concours white glove restoration. But the only problem I can for see is the adhesive failing. As such a spray on heat barrier sound deadener such as Lizard Skin would last longer.

Big Dave
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post #3 of 10 (permalink) Old 04-21-2018, 10:53 AM Thread Starter
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Thanks Dave.

Yes, I am restoring the car to original and not for speed. However, I don't want a material which is to heavy. I originally bought a floor insulation from Classic, but is it very heavy. Similar to the pads which were installed from the factory.

Thanks again.

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post #4 of 10 (permalink) Old 04-21-2018, 04:39 PM
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It's a tough call on how much and what product to use in 50 yr old convertible isn't it? I mean, Top up, windows up and new rubber seals and it still isn't anywhere near as quiet as a 15-20 yr old car.

I'd be curious to hear the sound dampening that comes with any HVAC product because it's hard to fathom that it would be as good as a layer of the typical sound deadener. I basically agree with Dave though, the sticky/asphalt/rubber stuff is more directed at stopping sound wave travel along expanses of metal. It has a secondary factor of heat blockage.
The manufacturers clearly all state that for the sound dampening aspect, you only need around 40%-60% coverage, but you see people and car shows doing a full coverage all the time because there of that secondary aspect of heat blockage. (and sometimes it's other peoples money!)

I sucked it up and did the full coverage, way up into the toe-boards and Firewall, a couple of sheets in the door and back seat sides and trunk separation panel. THEN, because I'm a sucker for punishment, I did the extra noise/heat blockage you get from the foam-style sheets. (if I recall correctly, they are better at air-bound noise blockage and the heat blockage is secondary.)

All in all, I like Hushmat the best for both products, and they supply a ton of global auto manufacturers so that's gotta be worth something.
they aren't cheap though, so I bought some of their good stuff for the firewall/toeboard and tunnel, then bought Eastwood and DEI for everything else. (Eastwood was having a big sale)
**Note that Hushmat's foam product is adhesive backed. The stuff is fantastic! I believe the DEI foam product is NOT adhesive backed.

Here's my thread from just last year.


Last edited by BA.; 05-11-2018 at 11:21 PM.
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post #5 of 10 (permalink) Old 04-22-2018, 02:01 PM Thread Starter
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Thanks for sharing. Great post from last year. You have a great point which I was thinking also. It going to be hard to keep the noise out in a convertible, but hopefully it will help. I am starting to think it may be best to use a product meant for a car and pay the price. I been working on this car for years and it seems stupid to cut corners at this point. Thanks for all the information.
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post #6 of 10 (permalink) Old 04-23-2018, 09:09 AM
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Another option is bed liner spray. This is permanent though, so be sure it is what you want to do. Also this will add some weight, but is that really an issue in a convertible that most likely is not being built as a drag car. The liner will also protect the metal from moisture in such cases of a leaky seal, heater core goes out, or for some reason your top is down when it rains. Granted that doesn't protect the soft interior components, but at least you don't have to worry about a wet carpet and liner causing rust in your floor boards.
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post #7 of 10 (permalink) Old 05-11-2018, 10:28 PM Thread Starter
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Thanks for another option to consider.
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post #8 of 10 (permalink) Old 06-13-2018, 02:43 AM
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Thanks for sharing this content. very useful thread.
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post #9 of 10 (permalink) Old 06-13-2018, 08:12 AM
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Originally Posted by profilehair012 View Post
Thanks for sharing this content. very useful thread.
Hope you can find the parts you need for your full size Chevrolet rear wheel drive V8 car in Amritsar, Punjab, India

Big Dave
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post #10 of 10 (permalink) Old 06-29-2018, 10:09 PM
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I'm dynamatting my 61, FWIW. I was sold on it when he put me in a 40 Ford they are doing ahead of me ... and that Ford wasn't made out of aluminum foil. They had the driver's side done, pax to go. No contest. muffle it out. loud outside, quiet inside.

1961 Impala. 4 door. 283, turbo 350. Imron Midnight blue metallic with silver stripe.

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