Some weights for soundproofing in 74-89 cars (weights in lbs)

heres the pelican thread on that replacement internal sound pad from Appbiz in the states

http://forums.pelicanparts.com/porsche-911-technical-forum/425369-lightweight-interior-firewall-sound-heat-pad.html

$89 so about £65 not too bad but have to factor in shipping. Only weighs 2lbs !! that’s a huge saving over the 13kg OEM padding. Its die-cut so no mincing around cutting to fit. Im pretty tempted to go for one. May see how easy my current one will come out first.

Other options are using Dynamat extreme at 1.1kg per metre squared or Second skin audio soundproofing. Probably cheaper but more time consuming to lay and cut.

Be nice to know the actual efficiency of the newer soundproofing compared to the OEM old worn out stuff.

another good thread here on internal soundproofing:-

http://forums.pelicanparts.com/porsche-911-technical-forum/482835-sound-deadening-stuff-floor.html

ah, this may help also...a sound deadener showdown !

http://web.archive.org/web/20080702090717/http://www.sounddeadenershowdown.com/

here's the rear parcel shelf/firewall pad that mark was talking about.



and here's the dynamat Extreme:

A guy i know who works for Ferrari Formula 1 team in composites has highly rated the Dynamat stuff. He said they used it on the Mclaren road car as was best bang for buck soundproofing. Cant get a higher recommendation than that !

I'm going to investigate whats under my rear seats at some point this week.

Quote: MarkJ at Apr 19, 2010 9:49:39 am

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A guy i know who works for Ferrari Formula 1 team in composites has highly rated the Dynamat stuff. He said they used it on the Mclaren road car as was best bang for buck soundproofing. Cant get a higher recommendation than that !

I'm going to investigate whats under my rear seats at some point this week.

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Cant get much better than that....(apart from if he worked for Porsche  ).

Im going to go with Dynamat extreme like the picture I posted above.  Pretty much cover the entire back seat and parcel shelf and side panels.....

Finally took my rear seat back off last night to have a look-see. The Porsche soundpad was there in all its heavy glory! For a split second or so i thought 'hmm, shall i start pulling it out' but a quick glimpse at the thin metal plate below it seperating your inner space from a screaming 3.2 flat six made me think otherwise and i left it be. It looks in good condition so will be a brave move to take it out. I would really like to know what the db resistance is of the newer dynamat extreme etc against this old heavy pad as i'd hate to remove it, go through the rigmaroll of installing new sound material only to find its too friggin noisy. I guess we always have the option of adding another layer above the dynamat, some kind of vacuum or sandwich board soundproofing if its still too noisy.
I intend to replace my old lux-pile carpets with some new lightweight RS stuff so that would be the opportune time to replace the soundpad too.

Been reading up some more on the various soundproofing materials:-

It turns out that both Secondskin damplifier and Damplifier Pro come out above Dynamat Extreme in terms of quality, lighter weight and less expensive according to several tests and testimonials. Interesting and handy to know!

The best soundproofing option is to lay the butyl sound barrier first, stuck to the metalwork (ie one of the 3 listed above). Then use  a rubber mallet to hit the panel in various places noting the resonance back from the hit. You can lay successive layers of the butyl over the first, repeating the mallet test until you think you have achieved a required sound damping. Obviously more layers you use the heavier it will be, so down to your preference really.

Then ontop of the butyl sound barrier you should/can use a 'sound absorber' using closed or open cell foam materials. This top layer is to help soak up any sounds still resonating through your barrier layer. It also provides a decent bedding to your carpet when its laid over it.

The two layer combo listed above should weigh much less than your existing heavy old rubber matting/jute combo and be far superior at soundproofing.

Its a project i really want to do on my car as hate the thought that i am carrying around 35kg of duff old soundproofing. Will accumulate the materials and new RS carpet set at some point and when i feel brave enough, attack it !

If someone else feels likewise we may save a few quid on sharing the cost of the soundproofing material 

Quote: MarkJ at Jun 10, 2010 2:30:08 pm

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Been reading up some more on the various soundproofing materials:-

It turns out that both Secondskin damplifier and Damplifier Pro come out above Dynamat Extreme in terms of quality, lighter weight and less expensive according to several tests and testimonials. Interesting and handy to know!

The best soundproofing option is to lay the butyl sound barrier first, stuck to the metalwork (ie one of the 3 listed above). Then use  a rubber mallet to hit the panel in various places noting the resonance back from the hit. You can lay successive layers of the butyl over the first, repeating the mallet test until you think you have achieved a required sound damping. Obviously more layers you use the heavier it will be, so down to your preference really.

Then ontop of the butyl sound barrier you should/can use a 'sound absorber' using closed or open cell foam materials. This top layer is to help soak up any sounds still resonating through your barrier layer. It also provides a decent bedding to your carpet when its laid over it.

The two layer combo listed above should weigh much less than your existing heavy old rubber matting/jute combo and be far superior at soundproofing.

Its a project i really want to do on my car as hate the thought that i am carrying around 35kg of duff old soundproofing. Will accumulate the materials and new RS carpet set at some point and when i feel brave enough, attack it !

If someone else feels likewise we may save a few quid on sharing the cost of the soundproofing material 

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Sounds like (no pun intended) that you are becomming the resident expert Mark. 

I wonder what the weight of what you describe will be compared to the 35 kilo OEM rubber mat?

hmm, not sure about expert, just collating all the useful info i can find.

Had a slight setback in my enthusiasm as spoke to somebody recently who had removed all his stock soundproofing and then replaced with 2nd skin damplifier pro with a closed cell foam over (ie almost my exact plan!)  He thought his car was still a fair bit louder than before so suggested that its 'mass' that really absorbs the sounds and therefore why Porsche used such thick rubber matting.
I still find it hard to believe that there isnt a more modern lightweight superior soundproofing to 24+ yr old rubber stuff !

I guess the bottom line is the weight saving v noise level equation, ie what your prepared to sacrifice to lose the weight. A 35kg saving is not to be ignored !!

Maybe the problem is people are only applying the one thin layer of Damplifier pro whereas some of the sound engineer types recommend to overlay further skins to achieve some absorption mass. I'm pretty sure whatever we put back would weigh a 10th, or just over, of what was in there.

Have a read of this article. 

web.archive.org/web/20080702090717/http://www.sounddeadenershowdown.com/

Looks like there are some very real good alternatives to Dynamat.

Quote: Pete at Jul 08, 2010 10:52:20 am

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Have a read of this article. 

web.archive.org/web/20080702090717/http://www.sounddeadenershowdown.com/

Looks like there are some very real good alternatives to Dynamat.

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see my second post in this thead Pete...already linked to that ! 

Engine compartment 4.11kg?

The ones we have weigh about 700grams!

Quote: MarkJ at Jul 08, 2010 11:11:52 am

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Quote: Pete at Jul 08, 2010 10:52:20 am

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Have a read of this article. 

web.archive.org/web/20080702090717/http://www.sounddeadenershowdown.com/

Looks like there are some very real good alternatives to Dynamat.

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see my second post in this thead Pete...already linked to that ! 

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Damn, Im an idiot.  Well spotted fella.  I deserve the hammering 

Quote: T911UK at Jul 08, 2010 12:53:53 pm

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Engine compartment 4.11kg?

The ones we have weigh about 700grams!

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Those tables are in pounds Matthew.