Soundproofing

JCoop · 02-07-06, 01:18 PM

Being such a pretty day yesterday, I decided to take the CAV out to Riverhead (abt. 70 mi. each way) to buy a Dynamat kit (the hood kit) which has enough sheets (4) of 20" X 30" or so for $150. I'm glad I did because the cabin noise after an hour's driving is definitely way over 95 db. So I started by lining the inside of the doors, and the vertical panels in the engine bonnet. The doors now sound like a Mercedes when you shut them [img]/ubbthreads/images/graemlins/smirk.gif[/img] but I haven't run the car again. I did not do the engine to cabin bulkhead piece as it already has a heat/silencer lining and appears to do the job. The entire underside of the bonnet is already lined with what appears to be Thermotec heat barrier sheets. Should I replace those?

So, has anyone done this and what areas do you recommend applying this Dynamat material? Someone suggested lining the top of the wheel wells, then spray with undercoating around it for both sound control and rocks that may potentially crack the exterior paint finish.

Thanks!
Ray

JCoop · 02-08-06, 06:53 PM

Mmmm, I guess nobody minds the noise...

Mike Dozier · 02-08-06, 07:16 PM

Ray

I drove my car a few times during the fall...not too bad.
Recently after a snow and sanding by the local township,
I drove same road and couldn't believe the noise the small
rocks/pebbles made striking the underside of the wheel houses.
I'm definitley going to undercoat those areas just on noise
abatement alone. It probably helps save the paint as well.
Regards

MikeD

DMatt · 02-08-06, 07:37 PM

Ray,

You might take a look at this stuff. I have never used it but after seeing it used on one of the hot rod shows it caught my interest. Seems like a lot of top builders use it. I'm thinking of giving it a try. It sure seems easier than cutting and gluing! Maybe someone who has used it will chime in.

http://www.lizardskin.com/

Bob Childress · 02-08-06, 09:49 PM

Hi Ray,

I spoke to you just before you bought your car in Phoenix. Congratulations and I hope you are enjoying the car and doing all the personal changes that will make it yours.

Many of the questions new owners ask have already been answered but they are just hard to search out unless you already know were to look. Try searching “cabin sound insulation.” I have extensively worked on the sound level of my car and eventually got down to about 85 db at a 75 mph cruise with total cabin sealing, Dynamat, a low 5th gear ratio, and tires.

Good luck with your new project and give me a call if I can be of help. Here are three pictures.

Bob

Bob Childress · 02-08-06, 09:50 PM

Picture 2

Bob Childress · 02-08-06, 09:50 PM

Picture 3

JCoop · 02-08-06, 11:00 PM

Wow! Thanks for the suggestions. And thanks Bob for the pix. I think I will definitely change the Thermotec around the roof of the engine bonnet with the new Dynamat heat/sound barrier. Unfortunately, the interior cabin is all upholstered but I'll remove the seats this weekend and see how difficult it will be to undo the liners. I'll post pix when I'm done.

Yup, I've been busy making this car "my" ride. I've redone all the wiring in the engine bay; not that it was wrong, just tidying up so I know where everything goes. I changed all the fluids as I don't understand why the previous owner had straight 30w in there. The lifters and valve train sounded pretty unhappy. I put 10W40 with a can of Marvel MO to clean up the internals and after a half hour of spirited driving, she quieted right down and hummed like a good V8 should. I don't hear any clicking and complaining back there at all anymore! Another couple of hundred miles and I'll switch to 15W50 Synthetic. I think I'll change the gearbox oil as well. Anybody know what the recommended oil is for the Getrag 5 spd?

Thanks all!

Mitch D · 02-09-06, 01:28 AM

Hi, Ray, GTA (German Transaxle of America) has rebuilt my transaxle and put in the new 3.22 R&P. Audi and John at GTA both recommended GL4 / GL5 lubricants or specifically the Redline 90W. At least that's what it says on the tag attached to the trans when they shipped it to Neal to test drive it.

Mitch

DavidTC · 02-09-06, 04:30 AM

Hi
Pictures are very useful when getting a feel for soundproofing installation BUT video is even better. Some of the relevant episodes of Boyd Coddington's American Hotrod on Discovery are useful in this respect.
David

Bill Musarra · 02-09-06, 07:22 AM

I keep a library of threads that i refer to when on that part of the build. I must have several hundred. You can find these threads on the search. If they are not there anymore just email or PM me for them:
Cabin insulation
Cabin sound insulation
Heat insulation
Insulation board
Sound deadening
Undercoating

Bill