School me on sound deadener

Joined
Jan 19, 2005
Messages
3,029
Location
South west utah
I need to install some dynamat or something in the rear of my rig to help with noise and I have never used this type of product before. I want to start with the area under the rear carpet and the rear quarter panels to try and mitigate my exhaust.


Questions:

1. Is there anything special I need to know before trying to install some sound deadener.

2. What brand? Dynamat or another brand?

3. What type? I see dynamat has a few different products, what type of dynamat (or other brand) should I use for underneath the rear carpet and the rear quarter panels?

Thanks
 

Delta VS

Supporting Vendor
Joined
Mar 12, 2018
Messages
1,823
Location
Boise, ID
Website
deltavs.com
Personal fave is the Hushmat brand. Have tried a bunch of the cheaper stuff (Noico, etc on Amazon) and always come back to hush mat. Probably similar to dynamat in quality (haven't used dynamat specifically, so can't comment to that with authority).

Key thing is to get the surface of your rig nice and clean. I like to take the old deadener off with dry ice/alcohol slurry, but plenty of people don't do that.

Putting Hushmat down as first layer (sticking to sheetmetal), then if you want to go bananas, put a layer of SecondSkin Mass Loaded Vinyl down.
 

Njck22

SILVER Star
Joined
Sep 24, 2017
Messages
907
Location
Texas
Many opinions on the best process, but for a fact based understanding of the motivation for NVH reduction methods, there has never been a resource better than the sound deadener showdown website that went down about a year ago.

Main point being covering you vehicle in 3 layers of sound deadener alone is not going to make your vehicle significantly quieter.
 

Irish Reiver

SILVER Star
Joined
Oct 24, 2015
Messages
2,099
Location
Orlando, Florida
I've done this process twice now and I wouldn't say i am accustomed to making the same mistake twice but I can say my reasons for doing it changed. The first time i did it i used the rubber stuff with a foam overlay (i cant remember the brand) i remember taking a decibel measurement before and after with my phone and it was something like 7 or 8 decibels quieter - according to my phone. I couldn't hear any difference apart from closing the doors. They went from a tinny dink to a solid thunk. I also noticed the truck was cooler in the summer but i never measured that so could be my imagination.
Second time round, my goal was to get the solid thunk and the cooler temps. I was happy with the end result.
 

Somebodyelse5

Enginerdin'
SILVER Star
Joined
Feb 9, 2014
Messages
3,406
Location
Tukee Town, AZ
Personal fave is the Hushmat brand. Have tried a bunch of the cheaper stuff (Noico, etc on Amazon) and always come back to hush mat. Probably similar to dynamat in quality (haven't used dynamat specifically, so can't comment to that with authority).

Key thing is to get the surface of your rig nice and clean. I like to take the old deadener off with dry ice/alcohol slurry, but plenty of people don't do that.

Putting Hushmat down as first layer (sticking to sheetmetal), then if you want to go bananas, put a layer of SecondSkin Mass Loaded Vinyl down.
why take the old deadener out? Toyota engineers literally did modal analysis to determine the optimal placement of that material. It's a lot of effort to pull an 1/8" of optimized deadening... to then put deadening right over it.
 

NLXTACY

Wits' End
Supporting Vendor
Joined
Dec 7, 2007
Messages
28,081
Location
Medford, OR
Website
absolute-wits-end.com
ISO-butyl rubber (roofing material) WILL off gas UNLESS you seal all the edges with aluminum tape. Did that in my 60 and zero smell and huge sound difference.

My LX and customer rigs I only use Dynamat. This is mainly has a matter of resale. Dynamat sounds a lot better than “Random rebadged butyl”.

There is ZERO need to remove the OEM asphalt. None. It’s a sound deadener. Ok, wait…caveat: I DID remove with dry ice because I was driving without a carpet for so long and the heat of SoCal just turned it to mush around the trans tunnel. I wanted it gone.

You absolutely don’t need to cover every single inch. 25% coverage takes care of it. But it looks so incomplete and I’d just never hand that to a custoner.

The Dynamat/Hushmat/Fatmat/etc is the first step. The biggest sound reducer is the MLV (mass loaded vinyl) layer with foam on both sides.

Definitely remove all of the old jute. I use a wire wheel on a drill and it pulls that all right off. You need sticky to stick, ya know.

Buy yourself a roller and spare your hands.

Use a foam hole cutter for the bolt holes. Saves so much time.

A8537B9B-3BB0-4FCD-A13C-67D28119E34A.jpeg


74F90E85-099F-4F5A-A5A2-70324351762F.jpeg


843347ED-BEEF-4E2D-B05E-0531F84E81BA.jpeg
 

Somebodyelse5

Enginerdin'
SILVER Star
Joined
Feb 9, 2014
Messages
3,406
Location
Tukee Town, AZ

edit: @NLXTACY beat me too it. My TLDR; Kilmat works well for the price, buy foil tape from home depot for cheaper, and the Noico foam insulation is nice.


I just finished up doing most of my 80. You don't need to cover everything with deadener, but it's hard not to want to. Just remember that as you get toward edge of panels, you are getting diminishing returns. Walk around and tap all your panels with your knuckle... doors, quarter panel... anything that sounds loud and hollow (think drum), slap a chunk of deadener in the middle.

I used Kilmat and Dynamat in my 80, Kilmat (80 mil I believe I used) is definitely my preference as the smaller sheets were easier to work with and a LOT cheaper, plus it doesn't off gas. Noico is 40% heavier, but it will offgas and smell according to the reading I've done. Make sure to take the seams (anything that won't be covered by foam, as any heat will help the butyl rubber squeez out and stick to carpet).

Next, slap some foam on top of that deadener. Noico 150mil insulating foam is a good option, this helps with temp insulation too. And then if you want to get crazy, add mass loaded vinyl (I didn't do the MLV so I am no help on where/what to buy).

I ordered everything from amazon and just used scissors. You can use whatever cheap foil tape you can find, I had a big roll from Homedepot that I used.

Here is a good high level explanation for the nerd in you:

Here is a good video doing a rad 70:


1642051670619.png
 

NLXTACY

Wits' End
Supporting Vendor
Joined
Dec 7, 2007
Messages
28,081
Location
Medford, OR
Website
absolute-wits-end.com
edit: @NLXTACY beat me too it. My TLDR; Kilmat works well for the price, buy foil tape from home depot for cheaper, and the Noico foam insulation is nice.


I just finished up doing most of my 80. You don't need to cover everything with deadener, but it's hard not to want to. Just remember that as you get toward edge of panels, you are getting diminishing returns. Walk around and tap all your panels with your knuckle... doors, quarter panel... anything that sounds loud and hollow (think drum), slap a chunk of deadener in the middle.

I used Kilmat and Dynamat in my 80, Kilmat (80 mil I believe I used) is definitely my preference as the smaller sheets were easier to work with and a LOT cheaper, plus it doesn't off gas. Noico is 40% heavier, but it will offgas and smell according to the reading I've done. Make sure to take the seams (anything that won't be covered by foam, as any heat will help the butyl rubber squeez out and stick to carpet).

Next, slap some foam on top of that deadener. Noico 150mil insulating foam is a good option, this helps with temp insulation too. And then if you want to get crazy, add mass loaded vinyl (I didn't do the MLV so I am no help on where/what to buy).

I ordered everything from amazon and just used scissors. You can use whatever cheap foil tape you can find, I had a big roll from Homedepot that I used.

Here is a good high level explanation for the nerd in you:

Here is a good video doing a rad 70:


View attachment 2892127

Ha! We are totally on the same page.

I think we can end the thread here :beer:
 

mudgudgeon

SILVER Star
Joined
Dec 17, 2007
Messages
5,596
Location
Across the pond, and upside down
If your using foam and MLV, taping or sealing gaps is critical to stopping heat and noise.

MLV and similar products are used in construction for sound deadening.
Installs without sealed joints and sealed gaps are measurably less effective than when everything is sealed.
The question becomes is the extra effort with it? There diminishing return on your effort as you get things more sealed up.
Don't leave the low hanging fruit

I agree a full layer of dynamat is not necessary to dampen a large flat panel to prevent resonance in a panel.
 
Joined
Dec 24, 2019
Messages
552
Location
Sydney, Australia
I have to say, I don't understand this personally. The sound is part of the fun! It's also useful on trails to be able to hear the bangs and scratches, that's useful feedback. And if I get my footwells full of water crossing a stream, that sound deadening looks like it'd do a great job at trapping moisture and promoting rust.

I'm guessing I'm not the target audience for this product though. :meh:
 

NLXTACY

Wits' End
Supporting Vendor
Joined
Dec 7, 2007
Messages
28,081
Location
Medford, OR
Website
absolute-wits-end.com
I have to say, I don't understand this personally. The sound is part of the fun! It's also useful on trails to be able to hear the bangs and scratches, that's useful feedback. And if I get my footwells full of water crossing a stream, that sound deadening looks like it'd do a great job at trapping moisture and promoting rust.

I'm guessing I'm not the target audience for this product though. :meh:

Prolly not.

I don’t cover the drain holes for that reason. You’ll hear bangs and scratches still.
 

Users who are viewing this thread

Top Bottom