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can anyone share their experience with sound deadeners. I am working on a 69 442 convertible and am ready to start working on the interior. I note there are some precut kits from Dynamatt and Flatline, Any thoughts on quality. Also do you think it's worth using this stuff inside door cavities. Appreciate your opinions
While re-doing my Rallye350 I bought all the pre-cut Dynamat parts as well as some generic rectangular pieces. I put them everywhere. My goal was to have the car as quiet as my wife’s Lincoln Continental! While I didn’t quite get there, the car is really quiet and it’s easy to have a conversation with the windows down at 60 mph.
I have used Dynamat on some other cars we owned and it works really well. If quiet is your goal, and the extra weight isn’t a problem, then put it in.
While re-doing my Rallye350 I bought all the pre-cut Dynamat parts as well as some generic rectangular pieces. I put them everywhere. My goal was to have the car as quiet as my wife’s Lincoln Continental! While I didn’t quite get there, the car is really quiet and it’s easy to have a conversation with the windows down at 60 mph.
I have used Dynamat on some other cars we owned and it works really well. If quiet is your goal, and the extra weight isn’t a problem, then put it in.
I sprayed the floor in my '72 convertible with LizardSkin which controls both heat and sound and used peel-n-stick CLD from NVX in the firewall, cowl areas and back seat areas. I also lined the backside of the kick panels and ashwell panels with 1/2" carpet padding. It may have been a bit overkill, but the floors don't get hot and the road noise and muffler rumble coming from below are not intrusive. Of course, driving with the top down at 40-6-mph the window noise is substantial.
The LizardSkin is sprayed in 2 steps; the sound control is applied first and the ceramic temp coating is sprayed on top. It's kind of pricey and you need the right spray gun to apply it properly but I think it was worth the effort for my project. Here's a pic of me car.
Rodney
The dark gray is the Lizard Skin sound control material, the white is the ceramic thermal barrier that is sprayed on top of the sound control layer.
In my opinion, it's not worth using sound deadener in a convertible at all.
It's great that you have an opinion, but do you have any experience with a convertible? Probably not. My wife had a 2003 Mustang Cobra convertible. You could hardly talk in the car, especially with the exhaust she chose. Took it all apart and Dynamatted the whole thing. Up the firewall, doors, floor, everything. At 60mph you could have a normal conversation with the top down, which you couldn't do before the Dynamat.
But it's probably not worth it in a convertible.....(sarcasim intended)
Not a Cutlass owner, but I have a ‘66 98 convertible and a ‘66 Starfire coupe. So I can give you both sides of the hardtop/soft top coin. First up no one makes anything custom cut for the big cars, but that’s not a big deal at all. You just get some shears, a couple of big Xacto knives and some gloves (Dynamat and other aluminum backed butyl rubber will slice your skin to ribbons). This is easily a couple day project depending on how far/fast you wan to go with it. I found it fun.
For both cars I used Dynamat from the trunk lip to the firewall, covering the floor pans 100%. This is overkill. I freely admit that, but I was trying to see how good it could get. If you go this route be sure your floor pan is rust free and clean to stick the stuff down and have it stop noise.
On the Starfire, I also covered a goodly portion (maybe 50-70%) of the rear wheel wells. For both cars I used the Dynaliner foam matting on top of the Dynamat and it helps the interior keep quiet and makes the carpet a little more luxe with the cushioning effect. For the quarters and doors I did not use Dynamat, but instead used 1/4” thick aluminum backed closed cell foam as replacement for the old tarpaper liner Olds used in ‘66. Better water repellent (foam vs. paper) and quieter too. I just custom cut the material (sold as Volara) in the shape of the old paper and filled in the interior door panel access voids with a second layer just for fun.
Spray glue helps a lot here - get a can or 2. That 3M dum-dum black stuff (and its solvent) help hold things in place too. Use dum-dum where you expect to be removing stuff for maintenance and glue where removal won’t be needed.
So, where did i wind up? With this approach you’ll get rid of the big noises - road rumble in particular. But then littler new noises come out - squeaks, suspension clunks that may have been masked before and other stuff. The insulation definitely reduces heat somewhat too, so that’s a win. As a separate project, I liked Dynamat so much I did the underside of my Starfire roof. That really helped reduce noise. And it has adhered well for 5 or 6 years now.
It is definitely worth it to do a convertible, but you’ll learn pretty fast that most of the noise is really coming from the fabric top and the windows. Even if the windows are very tight to the top and very well aligned.
So then, how to reduce top noise? Well, you can line it with something custom, which I have _not_ done, or you can put some 3” U-channel flap seals from Timlok on the top frame facing inward to add a little more insulation to the top and block some noise there.
Overall a worthwhile effort, partly for the result achieved and partly since it was fun. Let me finish by saing I liked Dynamat and was happy for the price, but there are cheaper, maybe better, alternative materials out there.
