Undercoating ( sound proofing )

[DWest]

Would undercoating the cab cut down on the exhaust noise in the cab or would it be a waste of money? I'm running a single muffler up front and when I'm on the pedal it gets pretty loud in the cab. All the exhaust pipe connections are sealed and have band clamps on them. I also checked the pipe for clearance and all seems to be fine. At cruising speed it's just fine. DW

 

[1dslram]

Spray undercoating will help, wraping the pipe to the back of the cab will help. Just rember wraping will shorten the life of the pipe but the pipes are cheap. I cut the sound by using two turbos that works real well with 5" pipe. I have also added 3/8" of sound and heat padding under the carpet, undercoat sprayed the inside of the doors and rear panels then spray glued more 3/8 sound proofing to the inside of the outer panels. Before I reinstall the side and door panels I will replace the plastic with 1/8 DynaMat type of insulation.

Bruce

 

[TomGolden]

I have done a ton of work to sound proof my cab, including exhaust pipe wrap and undercoating sprayed everywhere under neath the truck. The two most significant noise reducers for me were the exhaust pipe wrap and using some of the 1/2" Sound Stop foam around the oil pan.



Tom

 

[clawson]

This 1/2 sound stop foam does it get too hot and melt or anything? Do you have to take it off when you drain your oil? Tell me more getting ready in a month or two to try to tackle some of this soundproofing myself.



Chris

 

[KL]

Another thing which can make a noticeable difference is to do something to the rear wall of the cab. Its just bare sheetmetal back and acts like a drum. I put on some GSI sound deadening material (similar to dynamat) on the sheetmetal and put 1/2 inch soundstop foam over that. KL

 

[Scheibins]

Originally posted by TomGolden

using some of the 1/2" Sound Stop foam around the oil pan.



Tom

Is that where alot of the engine noise comes from?

Will that help with outside noise too?

 

[TomGolden]

I first put one layer of the GSI Dynamat-like material on the oil pan, then one layer of their 1/2 SoundStop foam. This was last summer. It is all still in place. I use 3M #77 spray adhesive on all my SoundStop foam, by the way.



This to my ears was far, far more effective at sound suppression inside than even covering the inside rear cab wall. I put 1 layer of the Dynamat-like material over the entire back wall, then 2 layers of the 1/2" foam on top of that, and it helped a little...



Also, when stading next to the truck with engine idling, the oil pan makes a very significant difference as well as it does from inside the cab. This summer I am going to make a removeable covering for the valve cover using both the Dynamat-like material and 1/2" foam.



Oh, and I cut a small round hole in the materials on the oil pan so I can easily drain my oil without having to do do anything to the foam or other material on the pan.



I have lots of pictures of all my sound deadening efforts in my Readers Rigs section, I don't remember if I have any of the oil pan though... will have to add some if not already there.



Tom

 

[DWest]

pipe wrap

Where do you get pipe wrap and how do you attach it? Also, should the undercoating be sprayed on the back of the cab between the box and cab? The worst noise seems to come from the down pipe. DW

 

[Lsfarm]

Check this out

There is a lot of info in this thread about noise reduction, Several products and techniques are mentioned and several photos.



The back wall of the cab, the floor under the carpet, The down pipe/exhaust pipe, the firewall , and the oil pan are the biggest noise sources in our trucks.



https://www.turbodieselregister.com/forums/showthread.php?threadid=40821&highlight=Noise+Reduction



Hope this helps, Greg L. The Noise Nazi