Sound deadener

[como]

Okay, so I started off by asking some friends, then moved to google, then searched here;

I've read from a few threads here on the boards that my best bet for a sound deadener is this liquid paint-on stuff called quietcar, but hear me out.

What I'm looking to do is drastically cut down on road noise, and engine noise in my '85- everywhere I go I'm being chased around by an angry little i-4 and she makes a racket! Road noise isn't so bad, but still an issue.

So since I've got my *whole* car torn apart for a paintjob (inside and out) I figured now would be an excellent time to do something about the noise- I figure I can pick up a gallon of this "quietcar" for it looks about $60 off their website (anyone seen it cheaper?) and that should be enough for a good 3+ coats of the floors, doors, walls, and interior roof of my aw11, but what else can I use in addition to it? I read in another thread that the "fatmat" I see all over ebay is a great product, but I'd like to hear that it really helps with the engine noise before I plop down some cash on it- looks like I could do the floors and backing with about 30 square feet, but I'd like to double-stack out back for the engine noise, bringing me up around 50 square feet, which if I get the "good" stuff from them will run me $130, which is no small change IMO.

[TomsMR2]

dynomat, fatmax, raamat whatever all suck. its a pain in the ass to use and it doesnt work nearly as well as it should for the extreme cost. it does the same thing that the quietcar does, which is stopping panels from vibrating and transmitting sound.

your car acts like a big speaker, road/engine noise hits it, it vibrates and transmits the noise to you. mats and roll on stuff add mass and change the harmonic frequency too low to hear.. ie, no noise transmission. no transmission means no transmission, piling more crap on beyond that does nothing. huge dimishing gains.

your only real option beyond deadening is filling the voids of the car with foam, or some other closed cell material. it has to be closed cell or it will mildew and stink. that blocks sound from transmitting in the first place.

a gallon of quiet car will make your car silly quiet. like bmw 7 series going 5mph quiet. i used a quart and its dramatic how much it stopped noise. if you went all out with a gallon you'd be satisfied.

bang on panels. the louder the noise, the more critical it is to sound deaden. the roof, doors, and floors are big ones, the rear firewall can definitely use some too. remove the speakers and get as much inside the door as you can as well.

[o6spdracer]

Send a PM to Mark_Dorman. He finished doing his MKII a few months ago and he is working on an AW11 too, so will be able to give you some good tips.

[como]

Tom- you sure?
The engine noise in this car is borderline silly, and there's a bunch of roadnosie too- I'd be more than happy to coat the underside of the hood, fenders, the floor, the interior of the wheel wells (since I've got the fenders off) and anything else with this quietcar stuff if it's going to help, I cant stand road noise... But do you really think that this stuff will block out *that* much engine noise?

I was thinking I'd probably do several coats of the quietcar stuff since I've read some great things about it, but since I've never dealt with sound deadener before, how much overkill should I go for? I figure I might as well buy a whole gallon (I've got a whole fleet of cars here, so I never have any problem buying "extra" material, since it *always* gets used)- Figure I did three coats over the firewall from the engine, and two for the rest of the interior (save a bit behind the dash, I'm not sure I want to rip out any more of the dashboard- what a nightmare!) and a coat on the inside of the doors (what I can reach through the holes, glass is out), a coat under the hood of the car, perhaps a coat on the underside of the engine lid (It seems to have been painted differently than the rest of the car and reverberates more noise than anything else), and maybe one on the underside of the rear trunk lid...)
What else can vibrate? Should I do the inside of the frunk?

I also plan to, at a minimum, put back in the 1" or so of mat crap I pulled out with the carpet on the rear firewall, but I was thinking I'd get something else to add in and help with sound insulation, since the engine really makes a racket. (I can't tell how much of that is engine noise vs vibration noise)

Also, what's the consistancy of this stuff? Think I could spray it like conventional paint? (If I'm going to do large areas it would be faster, methinks- and I've gotta get my hands on the gear anyhow for the paintjob)

[TomsMR2]

i have a less than a quart in my car. its enough to make a significant difference. i did a half assed job too, and really rushed it.. one sloppy coat, and its much quieter now. you'll be amazed, really. go take your hand and bang on your floorboard, it 90% stops all that noise after coating. 2 full quarts applied properly and you'd be golden. 3 would border on excessive.

its about as thick as pancake batter.. maybe a tiny bit thinner. you CAN spray it, i think they even sell a gun. you'd have to use a primer gun with a massive tip. it goes on so fast and so easy though, you can hand paint panels extremely fast. unlike paint though, you kinda want to lay it on thick. i had paint equipment too, but after getting it, painting it on really was the best choice.

im working on getting a bunch of sound canceling exhaust dampers. you bolt them to the ouside of the pipe and it cancels out resonation. i have high hopes for it, i hate engine noise too.

[como]

Alright, ordering it up

Anyone else think I should still buy some regular dampener?

Tom: I've never even *heard* of exhaust dampeners! Where do you get them? I was thinking I'd be replacing my muffler soon enough because it's too damn loud (appears to be completely stock, but possibly leaks a tiny bit) - what do these dampeners cost, and would they promote corrosion? (bolting them "to" the exhaust sounds like a good way to hold roadsalt to the metal, I think I have to drop my exhaust and paint it with some high temp paint while I'm at this project, because as it sits it all looks origonal, but being from the desert was only sandblasted for the last 20 years... already flashrusted since I got it back)

[como]

PS, where'd you get a quart? Website lists 1, 5, and 10 gallons.

p.p.s, delaying order until more information is available, apparently it's going to cost $17 to ship a gallon here from their website

[TomsMR2]

i have no idea where to get ex dampers! they come stock on luxury cars. they're about 2 inches long and bolt onto a bracket welded onto mufflers and pipes. most v6 cars have about 4 or so. im gonna ask the parts guys if they sell just the dampers, but i kinda have a feeling they dont. they're small enough that corrosion wouldnt be a big deal. they dont really reduce exhaust noise, they just cancel out that low toned annoying sound.. which is all i really want anyway. it looks like a rubber doorknob bolted onto the pipes.

i got a quart directly from quiet car. someone told me they dont sell quarts anymore, i dont know. i ordered up two probably a couple years ago.

[TomsMR2]

hmmm.. its been so long, maybe i got the edead stuff. they sell it in quarts, but i dont know.. i could have sworn i got quietcar. what i have now is in unmarked cans, and its gray.

Elemental Designs

[como]

oh no, so now there's confusion as to which product you're so happy with :-\

Looks like this e-dead stuff would be $65 shipped to my door for a full gallon of black, wheras the quietcar is CLEAR, so I'm thinking you've got the e-dead stuff...
it would be about $76 for a gallon of the quietcar. I'm not one to argue over $10, but now I'm curious if either would be a better product