What are the key areas to apply dynamat or similar products?

[Boston GN]

Looking to cut down on extra vibrations, door noise etc etc. What are the key locations to apply a dynamat type product?
I've noticed, also, when I took down my headliner that there was padding on the roof also. Was this gm's attempt at noise deadening? Worth it to keep those pads or replace?
TIA

 

[chopped39]

I'm doing a frame off right now. I pulling all the pads off the inside of the roof and using dynamat for the replacement I'm using ensulite for the floor and firewall. I was thinking about using dynamat in the doors but they are heavy enough already. This is the first frame off on a Buick for me so hopefully someone else will chime in.

 

[6APPEAL]

To cut down on noise you do not need full coverage of a panel. What you are doing is adding mass to lower the resonance frequency of the panel. How much a panel needs is up to you. Add a few squares of material and rap on the panel with you knuckle. If it gets quiet enough for you then that is all that is required. Ensulite and other foams are used for high frequency noise that the dynamat type products (mass adding) do not catch. But in reality, all sound deadening products should be used as a system to kill the various frequencies of noise transmission into the car.

The factory did attempt to address cabin noise, such as the pieces on the roof, the padding under the carpet and the tar/pitch covered pieces under/behind the rear seat and on the firewall. Locations for use are outer door skins, inner door skin, firewall, roof, floor. If the factory pieces on the roof are not letting go or falling down leave them alone, otherwise pull them off and replace. If you don't attempt to replace the factory deadener behind the rear seat you will have a lot of noise transmission from the trunk.

 

[hawkfan]

To cut down on noise you do not need full coverage of a panel. What you are doing is adding mass to lower the resonance frequency of the panel. How much a panel needs is up to you. Add a few squares of material and rap on the panel with you knuckle. If it gets quiet enough for you then that is all that is required. Ensulite and other foams are used for high frequency noise that the dynamat type products (mass adding) do not catch. But in reality, all sound deadening products should be used as a system to kill the various frequencies of noise transmission into the car.

The factory did attempt to address cabin noise, such as the pieces on the roof, the padding under the carpet and the tar/pitch covered pieces under/behind the rear seat and on the firewall. Locations for use are outer door skins, inner door skin, firewall, roof, floor. If the factory pieces on the roof are not letting go or falling down leave them alone, otherwise pull them off and replace. If you don't attempt to replace the factory deadener behind the rear seat you will have a lot of noise transmission from the trunk.

What would you replace that deadenr with? I was thinking some MLV(mass loaded vinyl) cut to size but that may be too heavy. I took the factory deadener out to put in my GNX brace and it is literally falling to pieces.

 

[earlbrown]

The easiest way to stretch of roll of that stuff is to take your knucke and start knocking on stuff. If you get a sold 'thunk' don't worry about putting material there. Everything you hit that rings like a bell is a candidate.

 

[Evaddave 87gn]

Before I knew anything about vibrations I covered the inside of my cabin with dyna-mat...I mean everywhere..complete doors..floor boards...pilliars..t-roof. BIG MISTAKE....as the guys above stated you do not need to cover every square inch.... I wasted a lot of time and money both installing it and more recently removing a good bit of it...

I didn't use the mat that deflects the heat..if I did it a again I would...

 

[turbo39151]

I did the floors, doors and roof of my GN and WRX... The WRX seemed to benefit more (at least in the feeling of solidness). It's still loud and the GN is still loud as well. I'm sure it's better than it was but it's nothing like silence of the modern luxury cars... Maybe some extra jute on the floor would be a better idea? Or a heavier sound deadener.

 

[Boston GN]

I just did the roof, b-pillar area, and outside door shell. I'm curious how everyone did the inside of the door without covering up all the adjustment bolts for the windows. That seems to be the biggest culprit of rattle.

 

[turbo39151]

Small strips here and there. Work around the bolts... I did not cover anything important.

 

[garyk1970]

1) roof
2) from rear window to floor (exhaust drone help)
3) doors
4) rear quarters
5) trunk floor
5) metal backing on firewall/front floor to heat

 

[6APPEAL]

What would you replace that deadenr with? I was thinking some MLV(mass loaded vinyl) cut to size but that may be too heavy. I took the factory deadener out to put in my GNX brace and it is literally falling to pieces.

A piece of MLV would work great behind the rear seat. MLV comes in several weights, 1/2 #, 3/4 #, 1 #, 1.5 # and 2 # per square foot are the ones I know about. All can be found at a floor covering place to avoid higher cost that car audio sites charge and saves shipping cost.

Unfortunately, weight is what gives sound deadening it's ability to deaden sound. So if you are concerned about adding a bunch of weight do the "knuckle rap test" that earlbrown and I mentioned. Garyk1970's list is really pretty good (except he left off the doors). By using MLV behind the rear seat I think you can get away with not doing the rear quarters and trunk floor.

The factory deadener behind the rear seat does fall apart with age. But that is what happens when you spray tar/pitch on jute, it is going to let go at some point.

 

[garyk1970]

Doors were #3.....