Dynamat

Wrecked944 · 10-08-2001, 05:37 PM

Well, I've got a couple of square feet of Dynamat extreme and I'm ready to start cutting and pasting. The factory sound-proofing long ago disintegrated on my 911 Targa. So it is very loud inside. Has anyone successfully used Dynamat to quiet a 911? I'm thinking of glueing the stuff to the sheet metal behind my rear seats and underneath the rear deck - unlike the factory stuff which goes in the engine compartment. I figure it will isolate the rear speakers better. Is this a good plan or am I totally off base?

Thanks,

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Janus Cole
1980 911SC & 1987 944

paulhagedorn · 10-08-2001, 06:39 PM

We put dynamat in our '74 911. It seems to have done a decent job, but I couldn't tell you if there was that much of a difference between no insulation and the dynamat. We put it all along the rear shelf and where the rear seats go...no rear seats in the car. I also put it in my 914 and it helped a little. The main noise that I hear from both of the cars comes from outside and around, not from behind me.

I would go for it, but the stuff does get heavy, if that is a concern for you.

Paul

Wrecked944 · 10-08-2001, 09:23 PM

Hello,

Thanks very much for the info. I hadn't thought much about external noise. I suppose I should - especially wind noise since it is a targa. This is all inspired by the colder weather. I'm entering my first winter with Froggy and I'm finding she is a LOUD girl with her windows rolled up. And as for weight, well, my plan is to weigh her down with every possible creature confort and then buy her a bigger engine !!

Thanks again,

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Janus Cole
1980 911SC & 1987 944

Zendalar · 10-08-2001, 10:32 PM

paulhagedorn, could I see pictures of your car. See, I have this -71 (serial says its -72) and it has no backseats and I would love to see how you have made it to look "clean"

SeaDweller · 10-10-2001, 06:27 AM

I embarked on a sound deadening trek some time ago, and had an eye opener. I noticed that while sitting at a light, I could hear other cars pull up, and in the rain, the "swoosh, swoosh" of cars going by was annoying. I pulled my rear deck and panel, installed some sound installation, and replaced my engine compartment sound pad with a factory new one. I thought for sure that the missing material in the old pad, in addition to the lack of insulation under the rear deck, was the culprit. Well, it wasn't.

Ultimately, I found that most of the noise was coming from the rear cabin vent in the roof, above the rear window. Those vents only have metal lip inside to prevent water intrusion, and they open up comletely into the car. The effect is no different than rolling down your windows a half inch.

I'm sure the Dynamat will make for a slight improvement, but I wouldn't expect a miracle.

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Michael
'78 911SC Euro

Wrecked944 · 10-10-2001, 08:33 AM

Ultimately, I found that most of the noise was coming from the rear cabin vent in the roof, above the rear window. Those vents only have metal lip inside to prevent water intrusion, and they open up comletely into the car. The effect is no different than rolling down your windows a half inch.

Thanks very much !! That is enormously helpful information. I will take your insight and inspect the vents. I may find a way to close them off. In addition, I am thinking of adding sound insulation to the doors or perhaps other interior panels to reduce road noise (I have way too much Dynamat on hand). I know many prefer to hear the engine and tires. And with the windows rolled down I heartily agree. But with the windows rolled up, I can barely hear myself think. Perhaps some research into the sources of common squeaks and rattles will also be part of this project.

Thanks again,

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Janus Cole
1980 911SC & 1987 944