[Brad Howard]

Hey guys:

Thanks for answering my earlier post regarding spray on sound deadening. I am not to keen on the Lizard Skin, I think that stuff would do better in the bed of a truck. Here is a little history so you can see what I am trying to accomplish:

I installed a blue printed and balanced 402 engine putting out 500 horse power. During the engine rebuild I installed large tube ceramic coated headers and a 2 ½ in exhaust system with 50 series Flowmaster mufflers. Although I ultimately got the performance I was looking for, the noise coming inside the car is more than I want and I am looking for a method of quieting things down inside the car so I can cruise along and enjoy the stereo without having to crank up the volume.

I have removed everything from the interior of the car in preparation for getting the car painted; essentially the body is a shell on the rolling chassis. Once the car is painted I will start reinstalling the dash, windows. and the rest of interior.

I had originally intended to lay Dynamat on the floors and have Dynamat sprayed in the doors and roof however, the only guy I can find wants a ton of money to spray the Dynamat. Do you guys have any alternatives to the spray on Dynamat for the doors and roof, my paint guy said if I came up with something he would take care it when he paints the car. What have some of you guys used?

Thanks DBH

 

[Ark68SS]

Use the search function at the top of the page & you can find a lot of info. example--
http://www.chevelles.com/cgi-bin/forum/ultimatebb.cgi/topic/21/4088.html?

BL

 

[1BadBu]

Check out the "B-Quiet" web site. Lots of good info and less expensive alternatives to Dynamat. This is something you should be able to do yourself. Use the self adhesive stuff and a roller on the door panels. Use something with heat-barrier properties on the floor. Go to a local stereo shop and inquire. Ask lots of questions. Spy on how they do it and then go home and do it yourself. My stereo guy just told me "do it yourself". He even shared some of their install secrets. Anybody with enough gumption to remove their own interior can sure as heck put in sound-deadener.

 

[chevelledude71]

I would agree with the do it yourself, but a question if you don't mind. Why would you put sound proofing in your roof?

I have all my interior out right now as well; except for the dash and two front seats. So, I will go by what you recommend or what you find out. Thanks

 

[1BadBu]

Wallace, my 70 came stock with insulation stuck to the roof. Most of the catalogs show it in the headliner section. I'd put it in for the insulation properties and count the sound deadening as a bonus. Semper Fi.

 

[docaudio]

I seen a lot of dicussion on sound deadening and thought I'd throw in a comment. As a professional sound engineer and El Camino nut, I have pondered this 'till I can't hear straight! Car insulation has two basic functions - #1 to control heat buildup or loss and #2 - sound control. When the cars were made 30+ years ago, heat was the main concern. Sound deadening was a by-product. A typical car body, being metal, will act like a giant bell when subjected to noise and vibration. It will want to resonate at a certain frequncy, and because of its size, it going to be a low and annoying pitch. If you can damp out the ring, like putting your hand over a bell, you'll have a much more enjoyable ride.
For heat control, I use the foil backed Dyanmat on floor pans, firewall and roof. Everywhere else I've used regular Dynamat or their spray-on product. One note, 1 can covers about 4 sq. ft. to the thickness that works, so you'll need lots. Since I have a pickup bed, I plan to spray it with a 1/4" thick coat of Line-x. This is about twice normal, but makes a big difference. I've used Line-x for speaker cabinets and besides being indistuctable, has good acoustic properties. If I had a Chevelle, I do a lot work to the trunk area. It's a big resonating chamber... right next to mufflers and rear axle. Also, don't forget doors... they transmit a lot of noise. Either spray in insulation or if you can do it, apply 6"x12" pieces of jute to the door skin. Keep it about 2" above the lower sill so it stays dry.
I'd plan on top quality carpet on top of good heavy jute on top of the Dynamat. The only real drawback to all this insulation is extra weight. But if done right, if shouldn't add more that 75-100 lbs.