Sound and Heat Insulating a
Diesel Hummer Part 3

Insulate Engine Cover Article

While you are working on the floor, you should also be working on the drive tunnel simultaneously.

The drive tunnel is a unique challenge, because you are combating both drive train noise and heat.

When I would take any of my trucks for 2 hour drives, the drive tunnel would get hot. This heat also radiates into the cabin. Not good.

Layer 1- Cascade Audio VMAX. This is the aluminum impregnated butylene sheet. I love this stuff because it does work. It sticks like crazy. It is heavy. It reflects and damps at the same time. It is a very effective as layer 1 of defense. Basically, I used three layers of this material on the sides and top of the drive tunnel. The Dynamat Extreme product is quite similar.

Again, use the roller and the heat gun to get it into place. Use sharp scissors and trim to fit. It is a no-brainer. Do several layers and with each additional layer, make sure you cover over the seams on the previous layer so that there is a "doubling" effect.

layer 2- I used the Maybach blue cotton shoddy material. The only difference that I could really discern between the purple and the blue Maybach materials was in the thickness and colour. The blue material is thinner. It might also be less porous and it seems to stay together better than the purple material.
In place of the Maybach blue cotton shoddy material, if I was to do this again, I would use the foil faced "Insulator" pad from Bonded Logic. www.bondedlogic.com It is slightly thinner than the blue Maybach pad and the foil face will reflect heat. This is what I recommend you do.

I again used a combination of spray adhesive from 3M and the DAP weldwood contact cement with paint brush to glue this material in place on top of the VMAX aluminum impregnated butylene sheet. Clean the VMAX with rubbing alcohol to guarantee that you have a good clean surface for adequate adhesion.

I cut a rectangle of the blue Maybach material and with an xacto and mat knife, cut it to fit while in the truck. I kind of test fit and trimmed at the same time to get it to match the contours of the drive train. This worked well and went quickly.

Layer 3- This defense layer is actually applied to the back side of the drive tunnel trim panels. I used a Cascade Audio product that is about 3/8" thick. It was a closed cell foam bonded to a thick vinyl/rubber pad that serves as a mass barrier. You see this stuff in the cabs of agricultural equipment. This stuff comes in a big roll. It is HEAVY. I took the trim panels that cover the drive train and removed the foam/rubber padding that was attached to the inner surface. This again is factory AMG material that is not very effective. I used the padding I removed as a template. I traced directly onto the new mass-loaded vinyl barrier that I had and cut with Cutco scissors. I then glued it back onto the inner surface of the trim panel using a combination of spray adhesive and clear marine aquarium silicone. All of the borders I then sealed up with silicone. I did glue the panel with the foam rubber side down first. It is closed cell, but it took the adhesive better than the vinyl side, obviously. This is the best way to install it, because you essentially have the vinyl blocking any noise that is going through the blue cotton shoddy that is glued onto the drive tunnel.
Do a test fit and make sure everything fits.

Kick Panels

The Front Kick Panels are a big source of road noise on H1's. After removing the kick panels, I installed about 3-4 layers of the Cascade Audio VMAX. This really helped. Using a sheet of cardboard, I then filled the cavity with expanding foam. You need to be real careful with this stuff so that it doesn't get out of control, but it does work. I did sand it down afterwards and used an xacto to thin it down a bit. Use gloves, otherwise, you will look like a leper if you get this stuff on your hands...The VMAX really helped. I can knock on the front fenders from the outside of the truck and there is no resonance and it feels much more solid. The back of the kick panel trim panels were again treated to a single layer of blue Maybach shoddy material. I cleaned the panel and glued it on. The audio sounds much better in the truck from just these simple upgrades. This was an added and unexpected benefit.

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