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Hmmm.. this is really interesting...I will have to examine this area more closely. If indeed the recess communicated with the wheel well covers, this may be a huge source of noise entering the cabin both from tire noise and exhaust as it would act like a funnel for sound, and isolating these recesses and super insulating them may make a tremendous difference in the sound levels...
Yeah, I think I need to have another look, too. I've been planning to put dynaliner on the forward side of the rear wheel wells. Maybe I'll try that sooner rather than later and have a peek at the other side of the holes.
 

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In the November 22 Autoweek, there's an article about the news Chrysler 300, and there's a paragraph on what they did to reduce NVH: " two 8 foot long composite underbody panels, dual pane windshield and front windows, body cavity silencing foam, underflush roll-framed doors, triple door seals, and acoustic wheel well liners." Well, our entire cars are composite, and we can do body cavity stuff, whereas windows and seals no luck, but the wheel well liners sound like the logical next step?
 

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I agree with you Dylan - the wheel arch liners are the next logical step.

Too bad I already put my rear shelf back on and both seats back in; can anyone with a decibel app see the difference between existing and blocking up the empty sides on either side with a creative layer of sound deadening?

It's going to be tough to figure out a shape that will fit into that cavity to place deadening materials on...I put some deadening into that recess while I had the rear plastic bulkhead off but doubt it is going to do much other than some *slight* sound absorption through the top layer foam.
 

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Considering that is made for the home, I doubt the ASTM standards will still apply for non-combustability and rotting. Seems like a huge mess that, as it was designed to do, will get everywhere and is pretty tough to get all of it out. It would be light though so that's a plus.
 

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So after the interior, the obvious next step is to reduce the resonance around the exhaust. The aluminum diffuser, heat shield, and license plate all surround that bomb. But will the damping material melt? I stuck a few square inches on the diffuser just below the stock muffler, drove around a while, and measured temperatures around the back while the engine idled.

Here are the temps I got:
Stock Muffler: 320F
License plate exterior 110F
square of damping material on diffuser 148F

There are no temperature specs on the material, but Damplifier Pro claims:

"High temperature butyl adhesive with increased elastomeric properties"

"The ultra thick foil on Damplifier Pro offers three thermal insulation benefits.

First, the foil acts as a radiant barrier, reflecting heat back towards the source. When used on the firewall, this reduces the amount of heat from making it in to the cabin of the car. Less heat means cooler temperatures. Pretty simple. [*Note: the foil is painted black, so it doesn't reflect heat directly. black will absorb it and then re-radiate it]

Second, the foil heat shield on Damplifier Pro dissipates heat by increasing the surface area, allowing for thermal dissipation and reduction. [*I don't understand this claim]

Third, the butyl layer slows down any remaining heat on its way in to the cabin of the car. The longer it takes the heat to get to you, the more comfortable you are."
 

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zuspiel and psoup, another thumbs up for all your descriptions!

2 quick questions:

1) Will DAMPLIFIER PRO do the same job as DAMPLIFIER in the sound deadening project described in your posts?

2) Is this one -> DAMPLIFIER PRO SOUND DEADENER 5 Tiles = 8SQFT on eBay (end time 12-Feb-11 09:53:17 GMT) the correct Damplifier Pro to be used in the proccess, along with LLP ??????

I am asking because I am located in Greece right now, and this add on ebay is the only shop that I found and that ships Damplifier (unfortunately ONLY the PRO one) worldwide:(:(
 

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Discussion Starter #168
Damplifier pro is exactly the same as damplifier except the butyl rubber layer is 2x thicker...The foil constraining layer is exactly the same as far as I understand...Theoretically it should be about 2x as efficient...BUT it is double the weight...
 

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Discussion Starter #169 (Edited)
Are you in the UK? 5 sheets of Damp Pro is $50.00, plus shipping...which I guess if your in the UK after shipping and VAT that the ebay may be cheaper...BTW 5 sheets are 10 sqft not 8 as listed on the ebay listing...assuming the sheets are full sheets (2 sqft per sheet).

EDIT: Duh, your in greece as per your post.
 

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Unfortunately I am in Greece:shrug:

So this ebay advertisment is the only choice i've got.

So I may well use Damplifier PRO, without nothing changing in the proccess, right?

Assuming I use about 20sq2 m of Damplifier PRO in the Elise, how much more weight would this add, compared to the simple Damplifier???

Also, the Damplifier Pro being twice as efficient, you mean in Sound deadening, or just in vibrations deadening?
 

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Discussion Starter #171
Correct, you can substituted Damplifier Pro for the Damplifier, it weights I believe about 0.6 lb/sqft comared to about 0.3 lb/sq for damplifier....

However, there are many brands of products out there that are nearly identical to damplifier and LLP...You may be able to find a different brand in that region that will do the same for you. Here is a few other brands of sound deadening products, I don't know anything about international availabability though.

Hushmat
Cascade Audio
B-Quiet
Dynamat
Second Skin Audio (this is the damplifier people)
 

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So, I was under my car the other day (imagine that), but this time the engine was running. I was looking at the panels and noticed that the front panel was vibrating like a bass drum. Anyone put damplifier on that? I may give it a whirl, although with its position, I'm not sure what it would do in regards to cabin noise.
 

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Discussion Starter #173 (Edited)
Well, over the weekend I figured it was time to address the side gap areas next to the firewall.

Materials:
1 sheet 1" x 2 ft x 8ft insulation foam from home depot ($5.35)
1 bottle gorilla glue
1 bag of polyester fill from Jo Ann's fabric

I tried to install the foam as 2 big pieces (one top piece and one that went into the swoop thing), but was unable to because I couldn't get the piece in place. So I cut them in half and installed in 4 strip blocks. After installing, I stuffed as tight as I could the batting behind, which keeps the pieces in place solidly. Once done, place the LLP overtop...I have not been out driving yet, since the interior is still in pieces...but this should thoroughly isolate these areas...The foam and batting is neglible weight.

To estimate the shape of the swoop for the foam you can rough sketch the arch from the outside of the car using since you can see the outside curve of the swoop.

With the gorilla glue, it works better if you mix the glue with a little water, maybe like 1 part h20 to 2-3 parts glue and then apply. The instructions on the bottle say to wet the pieces before applying the glue, however the foam will not hold water and the bottom seam you can see that the glue did not expand like it is suppose to; it should ooze out of the seams and expand as it dries. For the upper joints I did the water glue mix before applying and you can see how it oozed out like it is suppose to, this fills the cracks better and probably makes a stronger bond too.

The first 2 attached pictures are with the bottom half completed before the top half foam was added...You can see the batting behind the foam. There is a foam brace piece in the photo that was removed. This was simply to keep the pieced aligned while the glue dried since the batting pushes the pieces forward.

EDIT: Picture of LLP in place over foam added. Photo was taken before piece was glued into place.
 

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Hmmm. I'm curious to know what effect this has on the level of sound in the car. Conventional wisdom is that the bit that stops sound is mass.

Damplifier's purpose is to increase the mass of a panel, while giving it lots of internal damping so it does not want to resonate. Seems to me that rigid foam insulation should do pretty much none of the above. Let us know if your mod actually makes the car quieter.
 

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Discussion Starter #175
The foam was covered with LLP to give it mass. Part of the reason for doing this was that the shape of this area was very difficult to get the LLP shaped and onto, now it is a flat and easy to sound insulate surface.

The foam and batting is to prevent air movement, as I was figuring that that may have acted kinda like a bass box, tunneling sound from the engine compartment into the cabin.
 

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An admonishment:

Be aware that some of the glues, adhesives, and sound dampening products leech airborne chemicals in the cabin. The cheaper
products especially have this problem.
I used 1" dynaliner by Dynamat exclusively because it doesn't release any harmful contaminants into the cabin. It was tested for this according to Dynamat, which is more expensive but carries this guarantee.
The dynaliner did not diminish to any discernible degree the SC whine from the VF2 on my Elise, but lower frequency noises were lessened.

The Dynaliner is ultra-lightweight and fire-resistant as well.

-Robert
 

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The LLP actually reduces the SC whine noticeably (I suppose due to the mass layer).

About the glue contaminating the cabin air: Have you ever sat in a brand new Lotus? :D
 

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Discussion Starter #180
Oh, I forgot to mention. ALWAYS test your adhesives on all substrates. Many adhesives can melt man made carbon products, especially the light egg crate type of foams. . In general gorilla glue gives a great bond with no melting if other options are not viable.
 
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