18" wheels and tires will make the biggest difference. I placed Dynamat on the rear deck, but did not notice a big difference in reducing road noise. This was before I switched to 18" wheels. For me, the car is more enjoyable to drive with 18's.

 

I drive with fabspeed supercup exhaust everyday, it's loud as hell. So, I drive with earplugs on the highway and with windows down on minor roads. I know it does not help your case, but its fun to drive these cars, and that is what matters.

 

The black material was a black tar like material and a lot thicker and heavier than others I found It was called tsunami and I got it at circuit city. If you look in the outer body quarter panel thru the speaker hole, you can see porsche uses the same stuff for alittle factory deadening . But its just a couple little squares here and there. As a reference, I listened to the car with the origional carpet in. Then took it all out and had bare metal. It sounded loud and tinny. Then I put in the material and listened. It was back down to the origional sound as with the carpet in. Then when I put the carpet back , it was noticably quieter. And when I drove other cars at the dealer and went back and compared it to mine, mine was way quieter and lost alot of the vibration and tinny sound it had before.
Next I did this 997. I just bought the cheapest material I saw on ebay. It is the same sort of black material, a little thinner and has foil face. I didnt do as comprenhisive of a job, just got the main surfaces. But I still got about the same results. Alot quieter. then I did my tuning, with the agency power exhaust. Which is alot louder than stock. Now I think I am back to equal, or alittle quieter than stock. Im pretty sure Im still quieter than when I started. Id hate to be with out the material and be riding with the loud exhaust.

 

Any estimates of how much material is needed to cover the floor and rear area?

 

most are 12x12" squares. I had to use 2 packs. I think it was about 8 to 10 squares, But dont remember exactly. $50 to $75

 

Thanks. I'll be ordering some tomorrow. Next up: figure out how to remove the seats and get all the carpets and other stuff out of the back. It appears the installation of the stuff is relatively straightforward...just the removal and reinstall of the interior bits is the primary challenge.

 

Can you be more specific about the surfaces that you did cover to produce the difference? There seem to be mixed reviews of adding deadening material from 'no difference...50% quieter to a lot quiter' --- so it seems that proper placement / material choice is important as well. Would hate to tackle this just to find out that didnt use enough/wrong material or did not place it strategically.

Please keep this thread updated on what you end up ordering and any follow up regarding installation. Would love to follow along and figure out how to tackle this as well. The only thing that I have seen well documented on this thread is door panel removal - and its a start.

https://www.6speedonline.com/forums/...moval-diy.html

As for anything else its a toss up right now.

 

it is straight forward, its just alot of work. remove the quarter panels then the carpet. My pictures are there so theres nothing more to say. I also did lift the floor carpet and put some under there. every bit you do helps that much more.
when you see them put material in a car on tv, they do the whole floor on a car before they put any interior in it. Thats the the result you want to try to achieve.

 

How much would it cost to dynomat the car?

 

Take a look at this guy's post.. Might be helpful.

http://www.myturbodiesel.com/1000q/m...oofing-car.htm

 

I have recently purchased a 997.1 GT3 (my first Porsche), and was really disappointed with the rear tyre noise at highway speeds. I stripped out the cage and rear interior and was pleasantly surprised with the thick amount of sound deadening foam included under the OE carpets. However the huge rear arches were completely void of any sound insulation. I purchased a pack of Dynamat Extreme and laid a layer over all parts that I could reach of the rear arches. I used about half a pack, so not too detrimental to the weight. I also closed off the rear speaker holes with some alloy sheet as these looked like a good way of resonating tyre noise into the cabin. The result? Much quieter and the car is now much more pleasant at all speeds without that horrible tyre drone. So much so that I've fitted a GMG rear muffler delete resonator (bloody expensive, but what a sound over 4K revs). Yes, it take a bit of work to do this, but the results are terrific IMO. Highly recommended

 

I love it when people ask for some info on doing modifications to their cars and a bunch of trolls always come out saying if you don’t like it, should have gotten something else.
If you don’t have an answer to the question or some useful info to provide OP, don’t post anything at all. Just because you’re willing to put up with something doesn’t mean everyone else should. Don’t tell OP to get a Benz because this is how 911 was designed and you should just accept it. None of your business, if that’s what OP wants to do, that’s his doing.

Murph,
Thanks for the info. My car is a DD and I feel I need to do this as well. Once it gets warm here in Chicago I will pull the entire interior out and use Dynamat or Second Skin for the entire floor and sides, especially wheel arches. If not careful I can add 60kg no problem, will try and use the lighter stuff.
I also noticed that there are almost no wheel well liners. They are way too skimpy. I’m going to make my own to try and isolate some of the tire noise.
When I bought my car (traded in Mercedes S550 for a Carrera J ) it was a 3.5 hour drive back and I got a migraine from all of the noise in the car. My wife and I could not hold a conversation, it was so loud. I went down to 18 inch rims for winter and it’s still louder than I’d like it to be. My engine noise doesn’t bother me even with exhaust and intake work, it’s the road noise that’s making it difficult.

 

I'm curious about the extent to which the Bose sound system affects the sound. I have the Bose system, which is supposed to compensate for cabin noise. I also have Fabspped X-pipe, gundo-hacked cans, and some intake mods. For me, the sound is never overpowering, even though it's appreciably louder than stock. Admittedly, I like more sound, but unless I go WOT, I have no problem carrying on a conversation or listening to NPR. I'm no fan of the Bose, but I wonder if it has been quietly doing its job. I doubt that a Bose retrofit is the solution, but does the OP have Bose to begin with?

 

I've got Bose in my car as well. i don't think it does anything for the noise. Not the road noise anyway.

 

Please let us know if and when you decide to pursue the option of insulating the car better. I went through the same struggle with my first 997...first I changed out tires to the 'quietest', then read countless threads on insulating wheel wells etc...which after all that found the response has been pretty much unanimous somewhere in between there is no difference to there is been barely a difference for the work involved (and its fairly intensive to rip everything open).

I ultimately gave up on my 911 as a daily driver for that reason, and later bought a 997tt as a weekend car, which seems to work much better for my situation.

I feel like the 997 is bilateral as in the noise drives some people crazy and others ask ' what noise ', and have no issues with it at all. As a weekend car, I now welcome all the noise there can be, and want it as loud as possible, but as a daily, after a year or so of driving it is I realized that it is hard to turn a 997 into something it is not.

Good luck if you decide to go the insulating route, and maybe you will have better success then many others on here.