dynamat for engine bay, sound insulation Options

[bd1308]

okay, we all had this talk at the FFC. Some people love it, and some people didn't think it worked.....

does it really work or not....and where can i get cheaper stuff than the expensive dynamat branded stuff...this is down the road a bit.

b

[Twystd1]

r-Towle said it perfectly.

Ask a dozen differant sound engineers. And you will get a dozen differant solutions.

So once upon a time in Car stereo competition... Long time ago......... To kill road noise.... Hmmm... Memory..memory.. Oh yeah.... Here it is......In my head.......

My mix is the following.

1:)One layer of BLUE plastic (Looks like rubber tarp) tile underlayment that you can buy at Home depot. This is used to waterproof a shower and typically is used over green board. Feels like very thick rubberized plastic sheeting.
Spray glue it down with Scotch 77 spray adhesive in the rattle can. or the heavy duty spray glue of your choice.

2:) Add one layer of 3/16th - 3/8ths or thicker of neoprene rubber. It's just like wet suit material.
This stuff has lotsa little air bubbles trapped tha really deaden sound. And it's light. The closer (smaller) cell neoprene you get. The better it works. And the more it weighs. Get what you are comforatble with.
If you have the room. Thicker is better. Install neoprene over the Blue plastic. Spray glue down with Scotch 77 in rattle can. Your DONE

OR:

3:) If ya want to over kill it. Instead of the Blue plastic. Go to a roofing supply house and ask them for TORCH DOWN ROOFING MATERIAL with no sand. Sometimes comes in a roll with a thin sheet plastic stuck to one side. Sometimes no plastic stuck to one side. This stuff is very thick like 1/8th or thicker.

This is NOT rolled roofing like what you see on roofs. This goes UNDER the roofing you can see on roofs.
And no it isn't the thin felt paper you are used to seeing under the top of the roofs...
I.E. tar paper... NOPE... That ain't it eaither.

This stuff is TORCH DOWN.. Heavy shit... And it is an EXCELLENT but heavy sound deadning material in it's own right. Better than dynomat. And a bunch cheaper.
If plastic on one side... Remove plastic (if you can).(NOTE: This side goes down)

This is basicly a pure rubber and asphalt combination that is waterproof and last dam near forever. it is really dnomat on steroids. And you can put layer over layer.

I have doen door pannels. Fire walls trunks.. you name it. it's been done.

NEVER OVER anything that gets 190 degrees or hotter. It will smell. So not on floor boards of a single exhaust big block chevy ytruck with a gunked up Catalyitic converter. Makes the floor smoke. Ask me how I know...Please......

Teeners = no probs....

You can apply it with a torch or a heat gun. You get it so hot it melts onto whatever surface you put it on. NO GLUE NEEDED if ya torch it on.....

Can also be glued on with any kind of panel adhesive or flooring adhesive. ONLY use water based adhesive if you are using flooring adhesive. Test your glue on a spot on the material for adhesive quality's BEFORE USING!!!!!!

Ya don't need the vapors of a petoleum based glue in your car for weeks. USE WATER BASE if your gunna use flooring or panel adhesive... he says again.....

The trick here is to use two or more differant kinds of materials to mitigate the resonance of the ambient sound freqs. and engine sound waves. The more dissimilar materials you use that will work in this application and knock out the lower freqs. The better you are...

Cause each material damps out differant freqs. The material I mentioned above is dam good based on the end results you are looking for.

Really knocks down 1st, 2nd, 3rd, 4th, etc. harmonics down to a pleasant level.

Wheres a MLSA waterfall plot when you need one??????

That said... There is some aircraft sound deadning material that is freakishly good. Cept it's made for a differant harmonic and freq. than what we need..(Me Thinks)

Find a metal trash can lid or a good size piece of sheet metal. Glue some stuff on it.. hit it with a stick or a hammer before and after... you will get the idea of what works......

NEVER USE THIS COMBO OR ANY SINGLE PART OF THIS IN THE ENGINE BAY..

IT AINT HEAT I AM TOO WORRIED ABOUT. (but it's a thought)
IT'S THE PROBLEM OF TRAPPING MOISTURE TO THE FIREWALL

Thats my 0.02 worth.

Twystd1

PS: dont be in this car when it is burning... Makes for a hell of cough (IMG:http://www.914world.com/bbs2/html/emoticons/hanged.gif)