I'm wondering what everyone else saw for db sound in different parts of the cab before installing sound deadening. My car reads about 68 in the speaker corners, 69 in the luggage area and at the bottom of the luggage area 71. In the front seat, and doors 65. and 67 at the floors. Under dash is same as doors 65. If you have recorded the db's in your car before or after the sound deadening material. Also I was going 55 mph on relatively smooth road.

 

Omg! Really! It's a sports car!! Not a luxury sedan!

 

The whole car is noisy. Most of us end up putting the deadener on the ENTIRE inside of the car, including the doors, storage compartments in back, footwells and the floor. And you most likely will not be able to hear the dash speakers. Just experience talking here.

 

OK so maybe I didn't make myself clear. This is the third corvette I've owned, so I'm not surprised about the noise, and I'm not new to the car building scene. My first car was a V8 Vega in high school, and my last car was a factory five Shelby Cobra I was just wondering if anyone else monitored their car before and after the sound deadening. I've already purchased the sound deadening material and have the interior halfway torn down, so there is no deciding on if to do it or not. I also purchased some rubber treatment for the doors and t-tops because they are making a lot of noise.

 

About 100 with the side pipes and the windows down.

 

OK, I will jump back in after I understood what you are asking. I do not know of anyone who made the effort to take decibel readings at various locations in their C3. I also have a C6, and when I was putting sound deadening material in it, I did not come across anyone who took those readings in that car either. For the C6, the process was the same as the C3; Just put it everywhere. On the C3 it was a bare cabin, in the C6 I removed all the carpeting front and back but did not do the floors. Great improvements in both, although the C6 was quiet to start with. Not the C3. Good luck on your project.

 

With the tops off, windows down, and sidepipes, my son and I were able to have a normal conversation with budget headsets.

The tiny amount of insulation I added dampens the pinging from rocks flung by the rear wheels. I didn't want to add too much weight, though.

 

Hey, HEY HAAAY, My name's Richard Petty; can you speak Up ???

 

Just pulled the luggage area wheel well carpet out and someone went to the effort to take all of the padding out and install new carpet. No wonder it sounds loud, no padding or anything under the carpet and not the kind of carpet that has padding built into it. Just thin carpet.

 

I am curious to see where this goes. Interesting data you collected so far. I'm considering doing the same baseline test on my 73 survivor.

 

Sounds like you picked the wrong car.

BTW, my Hooker Max-flos sound wonderful.

 

badhcraft,
I checked all the obvious things. No rust, new dual exhaust, new tires, excellent paint, interior all there and looked ok. But then like anything once you get into it you find things that were done wrong or skimped on. So, I think I picked one in good condition, and I bought it one year ago so I'm still fixing things to make it personal to me, and I'd like to say almost finished but are we ever finished? like maybe a new 383.I don't know what's in the engine now but it's not stock, just not a 383 yet.

 

I didn't mean that there was anything wrong with the car, just that you may have been expecting something other than a noisier than usual 50 year old car.

 

bashcraft,
Thank you for clarification. The two corvettes that I previously owned, 72 and 75 were quieter so yes, I was expecting a slightly quieter car. When I started taking the carpet out to put sound deadening in I found out why. It's because someone had taken all sound deadening out and there was only thin carpet. My last sports car was a Shelby Cobra from Factory Five which had no top and side pipes that you could touch sitting in the car. didn't do a db test but it was really loud. Kept it for 10 years meaning fun outweighed the loudness. When I finish installing sound deadening it will be a little bit more civilized and a little bit more like the other corvettes I've owned.

 

OK, sound deadening and insulation as well as carpet is all in. Also new clamshell seats replaced stock seats. The rear corner speaker area was 68 and now is 66-67 ish. doors were 65 and still 65 because I didn't do them yet. The floor area was 67 and now a solid 65. The upper luggage compartment area was 69 and now 68. The bottom of the luggage area by the three storage doors was 71 and now 69. Both tests were on the same road driving 55 mph and my wife took the readings while I drove the car. So, it looks like 1 to 2 dbs lower everywhere except for the doors but then I haven't done those yet. What we noticed a big difference was the floor and center console area is noticeably cooler now than before. I wish I had taken temps before and after. I really thought it would make a larger sound difference than it did but it's done and did make some difference to the positive. I used 50 ml of sound deadening and 1/4 inch insulation. So, if you were to use 80 mil of sound deadening and maybe 3/8 insulation you might get another db lower. I will do the doors when I get some more door parts in and then I'll do the sound db on them and let everyone know but I'm expecting 1 to 2 db lower like everywhere else. My muffler is against my tire carrier so after I put my new headers in I'll have the muffler shop adjust to they don't touch. I'm thinking there is some noise from them transferring into the cab area and hopefully it will lower the db. Also, I'm getting a lot of noise from the t tops so new plastic and new weather strips and new adjustments. I'm making good progress and soon it will be more enjoyable to drive, because I don't like noises that should not be there.