Sound deadening, Thoughts?

MightyBoy tech questions and answers.
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Eamon
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Joined: Fri Apr 29, 2016 10:49 pm

Hi all

Ive looked around and as it turns out sound deadening is not much talked about in the MB community so i guess il start a thread.
 Anyway just looking into some sound deadening for the MB as road noise is quite loud on the highway and i currently have just tin for a roof. what do you all think on the different types of deadening (rubber butly / CCF). What would be the best pick price wise and effectiveness?, and if you have done sound jobs let me know what stuff you used and how it went.

http://www.ebay.com.au/itm/122197243042 ... EBIDX%3AIT

http://www.ebay.com.au/itm/12-Sheets-Se ... 2297659783?
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Brayden
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I've done parts of the the inside of the snot rocket with Dynamat and it made a massive difference to the ambience in the cabin. Downside is weight, which is why I placed the matting where it would make the most improvement. You could easily add 20-30kg by lining all of the cabin surfaces. I supplemented the Dynamat with 5mm closed cell foam matting to keep the weight down.
F8B EFI turbo - Three pots and a snail.
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Eamon
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Ah ok
when you say most difference for dyanamat and Closed cell do you mean the thicker foam on the floors or roof and dynamat in the door skins /firewall and parcel tray wall?

Will the pingjing stuff i have linked up there also work just as well as dynamat?
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Brayden
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The Dynamat was strategically placed wherever I needed to eliminate panel reverberation, and the foam was used to cover all large surfaces (to reduce road noise). Its hard to describe, but basically the Dynamat goes in squares wherever the panels can flex. If you're not worried about weight then you could just cover everything.
F8B EFI turbo - Three pots and a snail.
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Jeo
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I recently put a bunch of deadening in my CE Mirage. Definitely made a difference.

As for technique, check out this site Sound Deadener Showdown for a decent explanation of what you should be aiming for. Short version of their advice is that covering every inch of the car in dynamat type stuff will help, but it won't be that much better than doing say 25% of it. The real benefit comes from adding mass to dampen vibrations, then layering different materials to block different frequencies.
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Eamon
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Alright ive got a better idea of it now, with the doors did you not worry about them or did you just put some padding under the interior covers or actually on the inner skin?
Zuffen
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I used a foam based insulation that is self adhering on a past project and it was quite effective at stopping panel vibration without weighing too much.

As weight is our enemy I plan on using the foam again (I got it off eBay) in the doors, the rear panel and under the roof.

I have factory fitted insulation for the firewall (both sides) and some strategic areas around the front wheel wells.

All inner surfaces will be upholstered.

I expect it to be reasonably quiet but not struggling to carry the weight. 
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Eamon
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You are not joking when you say that adding sound deadening can easily add up to 20-30 kgs of weight.. the ping jing stuff just arrived and it weighs around 15Kgs 
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Eamon
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so I've finished doing both doors and they sound much more like a heavy car door instead of tin. I'm now wondering about the firewall, I have pingjing and some CCF should i strip the stock stuff off and line it all with new stuff or is there a better way to deaden the firewall?
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Brayden
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The factory insulation is just clipped on, although replacing it with butyl deadener won't do much because the firewall is possibly the stiffest panel on the body.
Wouldn't hurt if you reinstalled the factory insulation over the top, or switched it for something of higher quality.
F8B EFI turbo - Three pots and a snail.
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Eamon
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Alright thanks for merging those forums.
just need your advice on where the best points to cover with Closed cell and butly rubber to reduce engine noise and road noise
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Eamon
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hey all. while removing the factory sound padding I ran into a bump.. a nasty patch of rust just above the firewall so now I have to fix this and sound pad
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Eamon
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if its messy and it works... its not messy now time to clean it up
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