Noise reduction for Cummins Repower

[Steve Graham]

In 01 when I did the repower on my Scout I discovered that there was no previous attempt by the factory at sound deadening. The 4BT I had installed was as loud inside as it was outside. I did not take any db reading for baseline but I did last week for the baseline from now on. I had previously installed Accumat on the inside of the firewall and got the noise reduction down to a driveable level. The sound level measured was 87db on the A scale at 65 mph, windows up. Out side at idle I measured at 3' up and 3' from the Scout at the front axle and in front. The readiings I got were 85db, A scale on both sides and 88 db in front. My goal is 75db which is what I measured inside my wife's 94 Dodge Ram CTD. To day I took second measurement after applying QuietCar and I dropped 1db all around the outside and inside windows up at 65 mph I measured 84bd (A scale). That's a 3db reduction and I only coated the transmission tunel access, a panel that measures 12" X 18", the cowl area at the base of the windshield and I also covered the oil pan. The cowl has a 1. 5mm coat and the other have about a 1mm coat. Maximum coat thickness required is 3mm.

As soon as I can I'll coat more of the Scout and let you know the outcome.

All I can say is this stuff is great!

Steve

 

[dieselcruiserhead]

Awesome Steve. I decided I wouldn't put much pore time/energy/money into this body because I'm replacing it with a better/non rustd free one but maybe I should wise up and do it. It is pretty damn loud with zero noise protention. . I am also going to do some home depot carpeting after, FWIW...

 

[driverswanted]

I used roofing shingles all over my floor boards and transmission tunnel. Each layer gave me a dramatic reduction in sound. I also alternated softer layers with the harder shingles to trap and absorb sound. My alternating layer of material was roofing rubberized membrane. The adhesive between everything was urethane roofing adhesive out of a chalking gun. I must have two layers of shingles and three roofing membrane layers on the footwells and transmission tunnel. I still don't have a carpet in yet. I'm waitng on that because I'm putting two VW Jetta heated seats in before the carpeting job.

 

[Steve Graham]

I used roofing shingles all over my floor boards and transmission tunnel. Each layer gave me a dramatic reduction in sound. I also alternated softer layers with the harder shingles to trap and absorb sound. My alternating layer of material was roofing rubberized membrane. The adhesive between everything was urethane roofing adhesive out of a chalking gun. I must have two layers of shingles and three roofing membrane layers on the footwells and transmission tunnel. I still don't have a carpet in yet. I'm waitng on that because I'm putting two VW Jetta heated seats in before the carpeting job.

I applaud you effort to do it on the cheap. But I could not over look the fire hazard of roof shingles. Did I mention that QuietCar is fireproof! It does not burn! It does not emit dangerous fumes. After curing QuietCar will seal the metal from moisture and can be painted or covered with carpet.



Steve

 

[Willys]

Has anyone with the 4bt used a spray in(rhino) or roll in(durabak, herculiner) liner in the floor/firewall area? I'd like to see if its made any difference in sound. I don't really want to put carpet in the jeep- it traps moisture and will create rust problems.



I was reading about the quiet car material- it looks impressive. Is it hard like a spray in liner or spongy? Does it feel durable, or does it need something on top to protect it?

 

[driverswanted]

The previous owner of my truck had put two to three layers of Durabak on my floor and transmission tunnel. It had little effect on the sound from the engine. It did not quiet down until I put the shingles and roofing membrane in. (now for the CYA; "Perform at your own risk". There).

 

[Applegator]

Steve, interested in your plan and progress. We have tried different sound quieting material with limited success on our trucks. We also have a Case uniloader with a 4B engine and we have to wear ear muffs to operate the tractor. What kind of muffler do you have? Fred

 

[LAlessi]

i ran a 3" glass pack in my m715, and will do the same in the wc-53



heres is a thread from colorado k5 on sound deadening. you can spray bedliner on top of quiet coat... ...



http://coloradok5.com/forums/showthread.php?t=109696

 

[Steve Graham]

Steve, interested in your plan and progress. We have tried different sound quieting material with limited success on our trucks. We also have a Case uniloader with a 4B engine and we have to wear ear muffs to operate the tractor. What kind of muffler do you have? Fred

Fred,

I used a Magnaflow 5x8 oval x 24" 3" inlet/outlet. If I had room underneath I would have used a bigger one.

Link:Magnaflow



QuietSoluations also has stuff for commercial vehicles.

Link: QuietTruck

Steve

 

[Steve Graham]

Has anyone with the 4bt used a spray in(rhino) or roll in(durabak, herculiner) liner in the floor/firewall area? I'd like to see if its made any difference in sound. I don't really want to put carpet in the jeep- it traps moisture and will create rust problems.



I was reading about the quiet car material- it looks impressive. Is it hard like a spray in liner or spongy? Does it feel durable, or does it need something on top to protect it?

QuietCar can be sprayed on with a paint sprayer, rolled on with a paint roller or brushed on with paint brushes. It has the consistency of a thick cream, like cold maple syrup. I would think that it has to be protected if your going to walk or step on it.



Steve

 

[LAlessi]

steve, would you be comfortable using it as underbody sound deadening? id like to only spray the inside firewall and inside of the doors as theres no carpet inside and im trying to kee my vehicle looking original. the rest of the spraying would be underhood, outside firewall and underside of the truck.



do you mask it off like bedliner so you can still remove access panels?



im very concerned on the noise level of this new truck, and am seriously considering using this like undercoating.

 

[dieselcruiserhead]

I sprayed durabak/herculiner (same thing) hoping that it would deaden b ut again made very little difference. I would think the same thing with underbody too unless there was some sort of deadener underneath... Just my $. 02

 

[LAlessi]

well, i wish i could find someone who has used it. i would think rhinoliner (thick and rubbery) would be better than herculiner/duraback for sound deadening, but what do i know.

 

[Steve Graham]

Here's a link for a comparision between QuietCar and the asphalt coatings.



Steve

 

[Willys]

I figured I'd add this into the thread:

http://www.noisetek.fi/noise.htm

http://www.noisetek.fi/uk_index.htm



found it on the famous -90 Burb is getting a C thread.

https://www.turbodieselregister.com/forums/showthread.php?p=1117801&highlight=bitumen#post1117801

 

[Steve Graham]

steve, would you be comfortable using it as underbody sound deadening? id like to only spray the inside firewall and inside of the doors as theres no carpet inside and im trying to kee my vehicle looking original. the rest of the spraying would be underhood, outside firewall and underside of the truck.



do you mask it off like bedliner so you can still remove access panels?



im very concerned on the noise level of this new truck, and am seriously considering using this like undercoating.

The application guide says it can be applied inside and outside and as a undercoat underneath.

Application_guide

Steve

 

[driverswanted]

Steve,

I have access to a decibel meter. I'll see if I can use it and get the readings in my truck and get a comparison. If you have any more details on where you took your readings let me know.

 

[JasonBrown]

Check this stuff out. I have used it for cars with loud stereos (I used to install big stereos for a living 10 years ago). I have also used it in my dad's 1932 Ford street rod. It works pretty well.



http://www.dynamat.com

 

[LAlessi]

i like dynamat, but for me spray on is the way to go (if it works)



there is no way ill put carpet inside the truck, and dynamat will look like junk with no carpet

 

[Steve Graham]

Check this stuff out. I have used it for cars with loud stereos (I used to install big stereos for a living 10 years ago). I have also used it in my dad's 1932 Ford street rod. It works pretty well.



http://www.dynamat.com

Here's a comparison to Dynamat, again.

http://www.quietcoat.com/html/compare_to_dynamat.html



Steve