Recommendations for Piecing in Dynamat in a 1971-74 B-Body

[Bob Nossal]

I decided lay some Dynamat down to reduce vibrations in my 1972 Charger. I am getting ready to install the dash assembly but I want to lay the Dynamat first. I will probably just do the floors, doors and quarters(passenger compartment)...not going crazy with the stuff. Anybody out there willing to share some photos of a clean installation? Lessons learned? Dos and Don'ts? I have a bucket seat console car.

 

[Gold Rush]

I may have gone a little overboard with the Dynamat products; attempting to keep out as much west Texas baking summer sun and some of the Charger's new performance exhaust noise. In addition to covering all the areas you mention the underside of the roof and the floor got a layer of Dynamat then a layer of Dynaliner. The passenger compartment to trunk divider got Dynamat and DynaPad. Dynamat products conform to contours very easily. I found the roller is excellent for doing this.

Getting the floor done before installing the dash is a good idea but with the seats out it's not necessary. Plenty of room to roll around in there. Even for fat old men like me.. Here are a few photos..

 

[funknut]

The foil-backed butyl dynamat material is firstly a sound deadening product designed to eliminate the boomy sounds made by vibrations of large metal surfaces. It will reduce heat transmission somewhat as well, but is not the ideal product for that.

If you just want to eliminate that boomy/vibration rattle sound you really only need 25-40% coverage of the dynamat. You’re basically adding enough mass to those panels that they don’t resonate at ‘normal’ sound frequencies.

There are other products like closed-cell foam that are better for blocking heat transmission.

When I had the interior out of my car I did the floors, firewall and inside the doors and quarters with dynamat and this stuff for a heat barrier:

Noico RED 150 mil 36 sqft Сar Sound Insulation, Heat and Cool Liner, Self-Adhesive Closed Cell Deadening Material (PE Foam Sound Deadener) https://www.amazon.com/dp/B07TKXMPH7/ref=cm_sw_r_cp_api_glc_fabc_h06-FbWD68WX3

Heat barriers like the above should be done closer to 100% coverage.

the car is not fully back together so I haven’t done a driving test yet but there is already a big difference in sound just from shutting the doors.

 

[Bob Nossal]

I’m more concerned about sound deadening and eliminating the booming type noises such as when you close the door.

 

[funknut]

If you just want to eliminate the boomy noise then with dynamat you can get away with < 50% coverage on the large panels. More won't hurt you, just more cost and weight.

 

[Bob Nossal]

That’s my plan.