Sound management.

[Bruce Mohacsy]

Hey!
If anyone out there is interested in making their interiors more hospitable I found a cheap way of doing that. I picked some road noise insulation from and old school Chevy passenger van at the pic & pull yesterday. It was made up of three layers of product. A thick layer of felt, then a thick layer of butyl and on top a heavy black cardboard like product. As well I found a rear trunk liner from one of them foreign cars that was felt/butyl/plastic. I removed the dried, flakey tar sheet (sh*t?) "sound deadener" from my hatch area and cut these sheets out to match the hatch. The more flexible plastic coated trunk liner was used to conform to the shape of the spare tire well and to the rear tail light panel. I have enough van insulation to do the driver and passenger floors only so I'll be on the prowl for some more of the plastic stuff to do the transmission tunnel. Took the pony on my evil handling loop. Railroad tracks, potholes, washboard, then highway cruising. BIG DIFFERENCE. An afternoons work. Best $10.00 I ever spent. Somewhat cheaper than hushmat.

[AlamoGT]

Nice. I hadn't even thought of getting deadener from a pick and pull as I had my mind set on hushmat. I already have it in the garage waiting to go in though so I am committed to it now. Post up some pics if you have any.

[Bruce Mohacsy]

My experience with hushmat is that it works super good at damping panel "bong" but you still need to put a felt or foam Matt down afterwards. If you go to my photos section you will see my hushmat install section. I feel that the felt padding on the back of the original carpet, on top of the hushmat is still not up to the task so I will be searching for more cheap pic and pull sound barrier today.

[qtrracer]

Back in the day, the owner of this site (http://www.sounddeadenershowdown.com/) did a bunch of "non-scientific" tests on the various sound deadener products including the roofing material some use. It was very informative. Since then, the guy has moved into selling sound control product, but his original findings and some updates can still be found on that site. Might be worth a read for info only.

[Bruce Mohacsy]

Just a quick update for this thread. After installing a bunch of sound barrier and Hush Mat I find myself discovering a whole new level of squeaks and rattles that were covered up by the high volume of noise coming from the hatch area. Squeaks from the t-top fittings, sail panels and doors being the worst. Add to that a still unacceptable amount of cowl shake and I have a significant amount of winter work to do......... I haven't put in subframe connectors yet but I'm hopeful they will at least be purchased if not installed by the spring. The more I get into this the more I'm convinced that reducing NVH in these cars is more about enhancing structural rigidity rather than trying to cure the symptom. Stabilizing the dash is a whole other thing. I wonder if there is enough room under there to fabricate some bracing from the centre of the cowl down to the transmission tunnel. Or whether that would even do anything. I've noticed that my steering wheel bounces vertically rather than horizontally. I also noticed that the floor panels are only spot welded to the sides of the chassis. Do you guys think that seam welding them would be worth the trouble? Does anyone have any thoughts on this?

[brianj]

Well, can't tell you the results yet, but I seam welded my car, added subframe connectors and bedlined the entire floor. Hoping this helps. Going to add a layer of the foil backed thermal barrier as well. I can't tell you the results until spring, but I sure hope it's an improvement!

[Travis T]

Way I see it, there was a reason that convertibles had a brace pop riveted over those seams and that the 93 Cobra Rs had those braces actually welded on so it couldn't hurt.

[Bruce Mohacsy]

Travis.
Are you talking about the door sill on the inside of the car? Did they do the same to that as they did to the t-top/convertible doors? I never thought of rivets.

[Travis T]

No, this goes over the pinch weld below the rocker panels, where the notches are for the factory jacks. Pop rivets don't work too well though, they end up working loose over time.