Life_in_4Lo said:
Hltoppr,
If you are worried about future restoration, just use non-adhesive padding/sound material under the carpet w/ strategic pieces of dynamat (or whatever).
The largest gains are not by covering every square inch of metal, but by changing the resonance freq of every piece of metal. Even a relatively small patch of dynamat on a piece of sheetmetal will make a difference b/c it no longer 'booms'.
I think it has to be stuck to the metal, just placing it against the sides or roof will not be as effective as the adhesive because you are actually creating a composite sandwich when you adhere it to the metal. The metal can no longer amplify noise as sound cannot travel thru it the same.
good luck!
That is fairly close to correct. If you look at your large pieces of sheetmetal as if it were a speaker, then doing something to change its ability to flex, will change the sound it makes. If you add some mass to the surface, it will flex slower, and be a lower frequency. The idea is to reduce the frequence to a level you can no longer hear.
But sheet metal transmits high freq sound also, but not like a speaker. More like hearing voices through a wall. That is where the full coverage of the metal comes in. Wind noise, and tires humming on the pavement, engines, transmissions, transfercases, etc, all make high freq noise. Most of these noises come from the lower half of the vehicle. You will gain the most by working on this part of the vehicle.
If you attach heat insulation to the roof, and only glue it along the edges, you won't notice a lot of difference in noise reduction. IF you add some mass to the surface, and then add the heat insulation, you sould get both benefits, if you glue them both in place, 100%.
If you are considering a future restoration to the vehicle, why would you want it as an expedition vehicle. It will get to many mods to restore it anyway. If you remove all the external mods, and then sell it, the buyer will enjoy the quiet interior. You are driving it; make it comfortable for you. Forget about the next possible owner.
It sounds like the spray-on bed-liners are really great for protecting truck beds and fenders from scratches. I hear it also works fairly well on the inside of fiberglass '32 Ford fenders, to prevent rock damage to the fiberglass. Other than that, you probably don't want to use the stuff.
