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73-87 Chevy _ GMC Trucks => Interior & Equipment => Topic started by: ehjorten on August 13, 2018, 01:56:07 pm

Title: Cab-side Firewall Insulation and Noise Damping
Post by: ehjorten on August 13, 2018, 01:56:07 pm

So in the process of converting my 1991 V3500 to an LS I have been crawling around under the dash.  My stock firewall pad is falling apart!  I would like to replace it while I am working on the LS conversion.  I am not sure I want to replace it with the stock style jute and cardboard, but was thinking of something like a buytl rubber/mass damping material like Dynamat.

Does anyone have experience with this?  Have a material that they recommend?  I would like something that I can put on without completely stripping the firewall of everything mounted under the dash!

Title: Re: Cab-side Firewall Insulation and Noise Damping
Post by: Stewart G Griffin on September 17, 2018, 03:07:33 pm

i'll be wanting to do this soon also.

Don't have to time research at the moment.

In the meantime, you may want to view this though:
https://www.youtube.com/watch?v=Q-tkqZt4T-0

Title: Re: Cab-side Firewall Insulation and Noise Damping
Post by: VileZambonie on September 17, 2018, 04:35:35 pm

Whichever product you choose, I would make sure you use something black and not the silver foil because you can see it and it looks ugly above the carpet line. I used spray on deadener with the mat on top.

https://store.secondskinaudio.com/spectrum/

Title: Re: Cab-side Firewall Insulation and Noise Damping
Post by: roundhouse on September 17, 2018, 09:33:40 pm

I used Fat Mat everywhere  on every surface I could stick it
Firewall floor kick panels back wall  inside doors and ceiling

And I used a new reproduction of the stock jute  tar pad

Title: Re: Cab-side Firewall Insulation and Noise Damping
Post by: ehjorten on September 20, 2018, 09:25:32 am

I have been looking at Hush Mat.  I am leaning towards that product.

Title: Re: Cab-side Firewall Insulation and Noise Damping
Post by: JohnnyPopper on September 20, 2018, 03:28:22 pm

I've used Hush Mat on a number of cars, found that it cracks and separates at low temps. Also hardens to the point that I question it's damping properties.

For this next one I'm going to check out the guys at Second Skin, looks like they have a killer combo of spray on and mat.

Title: Re: Cab-side Firewall Insulation and Noise Damping
Post by: VileZambonie on September 20, 2018, 06:32:39 pm

I actually just got an email from them for a discount deal. Not that I'm endorsing, just passing it along.

https://store.secondskinaudio.com/specials/

Title: Re: Cab-side Firewall Insulation and Noise Damping
Post by: ehjorten on September 21, 2018, 08:28:52 am

The stuff that SecondSkin shows looks pretty good.  Their explanation of CLDs and MLV is accurate for addressing various noise sources and frequencies.  I like it!

If the Hush Mat stuff that you used JohnnyPopper was cracking and separating at low temperature, that leads me to believe that some of their product is asphalt based.  Terrible stuff to use in an interior, and it will dry-out, crack and separate over time and lose all effectiveness.

Title: Re: Cab-side Firewall Insulation and Noise Damping
Post by: JohnnyPopper on September 21, 2018, 01:10:05 pm

I spoke with Eric at Second Skin for about 1/2 hour yesterday, very knowledgeable.

Looks like the killer combo is spraying Spectrum to 3 mil and then overlaying with Luxury Liner. You can go further, like stuffing your doors with Overkill, but that is up to you.

Spectrum can be sprayed under your fenders and will hold up. Not good as a bed liner, can be painted over, I'm going to try it on this 1980 step I just brought home.

Done with Hush Crap.  ;)