ive basically taken care of the trunk lid and quarter panels, now i wanna do the trunk floor.. seeing that i cant use expanding foam for this application, any other suggestions or is dynamatt the way to go? if so, how many layers would acheive almost total silence in the trunk? lemme put it this way, im driving around with no back seat rite now so i can do everything i wanna do. i dont wanna be able to hear my stillen muffler through the trunk floor or road noise. what do the expericenced people in here think i need to do to for the best results?

 

How much money are you willing to spend on materials? How much floor space are you willing to give up? Height in inches or centimenters.

 

In my experience, it's virtually impossible to silence the exhaust without some serious sound deadening. Dynamat is intended more to keep music INSIDE the car, but has a good consequence with outside noise.

So don't expect to really "hear" any silence anytime soon without a project that's drastic...such as lining the car with a thin layer of concrete...haha. (go to elitecaraudio.com, they've actually talked about that before)

 

money? i dunno.. depends what were are talkin about. height?, same answer.. i dont want 8 inches of somethin if thats what your asking.. basically im just asking what my options are..

 

If money were no problem this is what I would do. Cover floor and sides with epoxy/hollow glass microsphere mixture. And a few layers of carbon/kevlar or plain kevlar for stiffness. Then put in 3-4 layers of home made syntactic polyurthane foam. Use a polyurehtane 'mix and pour' and mix in glass and or ceramic microspheres. The bottom layer would be a fairly high durometer and the top layer a low durometer. So the top is soft and bottom hard. This would allow attenuation of a mix of frequencies. The glass and ceramic microsperes are excellent insulators. And good thermal insulators are traditionally good acoustical insulators. A layer of ceramic paint is advertised as having an R value of 25. Finally add some carpet pading and carpet.

 

ummm... i really dont know what any of that stuff is, where i could get it, how much it is, or how to use it....

 

www.fiberlay.com
www.fibreglast.com
Read the tutorials. And search the web or a library for other information about insulation, sound reproduction/insulation, etc. Also check out: www.cascadeaudio.com
www.dynamat.com
www.abdllc.com
www.3m.com/microspheres/
www.crescentmoonfibers.com/audio.htm
www.technifoam.com

Also check the car audio mag sites for information.

 

ok.. thanks for all the help. before i embark on this journey of info you provided me, lemme ask you this first.. in my trunk, theres a peice of plywood that sits about 1" or 1 1/2" above the metal floor. the plywood is cut to fit the shape of the floor perfectly, so in a sense there's a "basement" under the plywood. the plywood is also cut across from driver to passanger side that forms almost two equal halves. these two halves are joined with a piano hinge so that i can flip up one side to retain access to my spare underneath. so theres one half that is stationary, and one that can be pulled up. for the half thats stationary, what im gonna do is use the same expanding foam that i used for my trunk lid and quarter panels to fill the underneath solid since its basically an enclosed area. now my question is about what i can use for the other half of that "basement" space, which also includes the well for the spare. can i just use home fiberglass insulation and adhere a layer on that part? my logic is i can get some with an r-value of 25, and just lay a peice in the spare well and whatever other space thats no covered. is this a good idea or a waste of time?

 

Rather than using the spray foam buy a sheet or two of the 1/2 to 2 inch thick foam insulation boards. The stuff that is used on the exterior walls of houses. Cut it to fit with a utility knife and bond it to the floor with liquid nails, epoxy, or some other really good adhesive - such as polyurethane. One 4X8 board can be cut to cover the entire floor a few times. So you could get a 1/2 to 3/4 inch thick sheet and layer it to get your desired 1 to 2 inch thick insulation. R-25 Myraflex or Fiberglass would be about 8 inches thick. Compressing it to 2 inches thick would reduce the R value. But the foam boards will be R5 to R15. Also, www.fibreglast.com sells polyurethane foam sheets as core material for boats, planes, sub boxes, etc.

 

i just used only 2 cans so far?how many cans? and how far up the panel did you apply it?

 

I know the guy who sells Raam matt for 90 dollars (50 square feet). It's an equivalent to Dynamat extreme, even more flexible. I've got it on my car, it really works.

So... let me know what you think!!!

 

Yeah, that new Ramm mat would be the **** if I didn't have to pay shipping to Va. And 50 squares is about perfect for the trunk.

 

so far ive gone through about 15 cans of the stuff i have. that did the entire trunk lid and driver side quarter. my friend just got me another case of 15. that should be more than enough to do the passanger side and whatever other little places i can find. i might also do behind my back bumper just to get rid of the rattles from there.. when i did the driver quarter i think i used about 4 cans. i tried to fill all of the empty space. put it this way, if you knock on my trunk lid, it sounds like your hitting a peice of plywood now..

 

Well are you saying it's good or not???
What do you mean by saing ****?

It's an equivalent to Dynamat Extreme. But cheaper.