[Ferrino]

When I have the main carpet and rear firewall covering off for the upcoming HardDog install, I was thinking of putting down a layer of sound deadening material underneath. For example eDead. How much square footage do you reckon I'd need for the main floorpan + rear firewall + both doors?

I was going to get the thinnest sheet (eDead 45) and then doubling-up where necessary.

It's $1/sq.ft.

 

[Im_In_San_Fran]

I don't know. But I wanted to say:
- That's a good price so just buy double your rough measurements.
- There's one thread where a pro-shop adds material on the engine's side of the firewall.
- There's a night-and-day difference if you just fill up your rear storage compartment (I used a retired goose-down comforter).
- There's a (night-and-day difference)^2 if you go hardtop.

 

[SuperWhiteGT4]

From a local forum:

"Well Ive seen alot of folks cover the interior entirely, and yes that was my orginal intent. However, the day I went to buy that dynamat at the local big city stereo place, coincidentally the Dynmat rep was there. When he overheard what I was going to do he says, "were more than happy to sell you all of our product that you want, but please let me show you my field demo". He had a 35 gal metal drum. Inside was a speaker system with a small subwoofer. He turned it upside down with no DynaMat and turned the system on. Then he installed one small piece of dynamat, about the size of a coke can on the bottom of that drum and the diff was like night and day. He then proceded to cover most of that drum and the sound reduction results were no better than with just the tiny piece. His explanation was such," most people think our product, or similar is for sound proofing, its not. Its designed to reduce sound resonance or vibration". I'm more than happy to sell you all you want, but you would be jsut as well off to strategically place it about the car, then buy a much cheaper felt mat to place between the floor and the outer area, which is what I did. I dont knock anyone for covering the entire interior as, simiarl to what Silver bullet has shown, to each his own.
And that was my plan. Luckily due to an honest salesperson/rep for the very company that makes the stuff, I saved quite a bit of coin for other things and still have a very quiet car."

 

[ju5tchi11in]

^^ that is very interesting to hear. Covering everything doors behind and under all carpeting seemed like the internets answer to sound dampening deadening reduction. First I've read about using it in spots, but makes sense. Intermittent dampening stops the flow of the sound waves.

Well it is also a lot less weight added of doing patches of it versus the entire surface area of the interior.

 

[HCS]

I'm going to try spraying rubberized undercoat from 3M on the front inner fender well. I'll see how it goes.

 

[Cotton]

Pillows

I took the advice of the guy that added goose down to the storage compartment except I added two fiberfill pillows. I also put two fiberfill pillows just below the storage compartment (behind the drivers and passengers seat). It seemed to help but when I drive it with the top up am sure I will be able to determine the extent of the improvement.

 

[OldMan]

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[ju5tchi11in]

Makes sense.

Larger patches on flat parts and small strips on ridges/ strip on each part (side, top, side)

Create dissonance so the waves are not uniform.

Another project added to the list, probably do this to the mk2 rather than the mk3.

 

[03txspyder]

They sell stuff at Home Depot called Peel and Seel that works as sound deadening as well. I used it on the firewall behind the seat and I notice a difference. Lots of review of people using it online. It's cheap and looks similar to Dynamat. I

 

[Ferrino]

I would not use the Home Depot peel-n-seal stuff. From everything I've read, it will smell awful under hot conditions (esp. firewall) as it contains an asphalt-based lining. I am thinking of using the Raamat BXT-II product, for the doors and firewall, and perhaps a few small portions of the main floor.

 

[03txspyder]

I would not use the Home Depot peel-n-seal stuff. From everything I've read, it will smell awful under hot conditions (esp. firewall) as it contains an asphalt-based lining. I am thinking of using the Raamat BXT-II product, for the doors and firewall, and perhaps a few small portions of the main floor.

Interesting. I have had no issues with the smell.

 

[OldMan]

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[OldMan]

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[Im_In_San_Fran]

I took the advice of the guy that added goose down to the storage compartment except I added two fiberfill pillows. I also put two fiberfill pillows just below the storage compartment (behind the drivers and passengers seat). It seemed to help but when I drive it with the top up am sure I will be able to determine the extent of the improvement.

Pack it as tight as you can...

 

[rcntype]

I was going to do something similar as well when I installed my rollbar. Then after everything was out I notice the firewall ALREADY has sound deadening material there. (actually i've also seen other panels of the car have deadener already like the door skins and qtr panel skins. Just a simple sized right patch for each area.) And I think they have installed just enough to deaden vibration without going overboard in wasting money and weighting the car down.

What you really want to do is a sound blocker type material, not a vibration dampener.

 

[plebian]

I'm going to try spraying rubberized undercoat from 3M on the front inner fender well. I'll see how it goes.

That won't do much at all. Most sound deadening products work with porous material, air between solid layers, using compacted coatings just transfers the sound from one side to the other. If you wanted to sound seal the area, a layer of spray foam and then rubberizing over that would be WAY more effective. Idealy you want a porous material between two solid layers with an air gap between that and the base surface. My first job was high end car stereo installing, at our shop we used to use a rubber chickenwire type of spacer between the body and the soundproofing material. The difference with the spacer is night and day, as the air itself does a huge amount of deadening.