RussB

I like my car to be quiet, both inside and out. I've been very happy with the results of applying Dynamat Xtreme to my '88 5KCSTQ's doors, firewall, and trunk lid.

Here's a well-done article on the practical aspects of quieting interior noise (with a goal of improving sound system quality). The author's comparative tests of materials will, I hope, discourage the endless "Plain old tar paper outperforms Noise Nuker Supreme and costs only a tenth as much" arguments:<ul><li><a href="http://www.sounddeadenershowdown.com">http://www.sounddeadenershowdown.com</a</li></ul>

Bloodred86

The problem with quiet is you cant hear whats going on with your car.

Randolph

Interesting. I've used that stuff before on a Fiero GT and it does work well. I've thought about applying some to the 5K but it's soooo time consuming. He brings up how Lexus and high end luxury cars are so quiet compared to cheaper economy cars which is very true in my exp. Audi seems to have a done a real good job of keeping the new S8 quiet with that optional Bang &amp; Olufsen stereo. 1000 Watts, 14 spkrs and supposedly you can't hear the radio on the outside of the car. Theres been various articles written about it already.

Randolph
87 5KCSTQ
93 928GTS

RussB

I'm impressed with the care that Audi went to even on our 5000s to control noise. Still, they were built to a cost. For example, each door skin has a small sound deadening panel glued to it, but it's small and I'm sure isn't near as effective as the better aftermarket materials. Also, every car manufacturer worries about CAFE (corporate avg fuel economy), so they must keep weights to a minimum -- especially on our 5ks with just a 2.2 liter engine to pull them around.

You're right: it IS time-consuming to cut and fit the material. I can't imagine paying full shop rate labor to have someone do this work for me. Then again, that's just the sort of job that I like, with low material cost and lots of labor needed, for a very desirable gain.

As I've needed to gain access -- doors, heater box, shifter mechanism -- I've been adding sound deadening material as I go, before buttoning up that portion of the car.

In addition to Dynamat Xtreme, I've got a sheet of 3/8" thick closed cell foam that, for example, when fitted around the 5-speed shift stick beneath the shift boot, substantially reduces perceived gear whine.

If you add Dynamat Xtreme or similar material to your 5K, I recommend starting with the inside surface of the door skins (take the opportunity to lube door check strap, latch, and window regulator while you've got the door panel off), because you'll instantly notice a marked reduction in road noise.

audi-bahston

I just finished reading the ENTIRE article... good stuff. I'm off to have a beer and finally collect those social security checks I've been working for all these years.

RussB

Dampening my '88 5000CSTQ's trunk lid was easy and (to my surprise) significantly quieted road noise.

It's easy, 'cause there's nothing to remove first.

I used kraft paper and scissors to make templates first, then installed cut-to-fit pieces of Dynamat Xtreme against the exposed trunk lid surface. The next step was filling the channels (such as the big X-shaped one) between the lid surface and its spot-welded stamped metal support with Great Stuff foam in a can ($6 from Home Depot), followed by trimming the excess with a razor blade.