Insulating the Turbo Doghouse

[erasedhammer]

I just finished up my 6.5 turbo swap from my old 6.2 and took it out on the road yesterday and practically went deaf going 45 mph. I had my 4l80 mated with my 6.2 before and at 50 it was relatively quiet, I could actually have a conversation at that speed. Now I'm screaming at passengers above 40 mph.

After some thinking I realized the only thing that changed was the doghouse. And the difference between the NA and turbo covers is drastic.
The NA cover has a solid 2 inches of thick rubber matting formed on the inside of it.
The turbo cover has.... 1/4" piece of reflective insulation. Does jack all for sound insulation. So I am going deaf because AM General thought it would be funny to skip out on putting sound insulation on the turbo doghouse. Noise cancelling for now.
I don't know if AM General ever made thick rubber insulation for the turbo doghouse, but it would be cool if it existed.

For now I am brainstorming ideas to deaden sound. So far I've spray the inside face of the cover with boom mat rubberized spray. I planned on getting a thick sheet of mass loaded vinyl matting and doubling up on that.

Does anyone have any creative ideas for insulating a bare doghouse?

 

[Carrera911]

Depends on how much much clearance you have behind the dog house. I think the ideal solution would be the 1 to 1.5 inch thick soft foam with the aluminum backing on it. That is used commonly for heat and sound deadening around engines and trans.


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[erasedhammer]

Depends on how much much clearance you have behind the dog house. I think the ideal solution would be the 1 to 1.5 inch thick soft foam with the aluminum backing on it. That is used commonly for heat and sound deadening around engines and trans.


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Ive done some research into lead rubber sheets and they seem to be much more effective than foam. I just don't know where to get the right stuff.

 

[Carrera911]

Ive done some research into lead rubber sheets and they seem to be much more effective than foam. I just don't know where to get the right stuff.

This is similar to what I was thinking of though not as thick.
Dynamat 11905 Hoodliner 32" x 54" x 3/4" Thick Self-Adhesive Sound Deadener https://www.amazon.com/dp/B00069QLVC/ref=cm_sw_r_cp_api_bdV2zbM2PK1ZV

I think a layer of the classic hard rubber 1/4 inch dynamat with a layer of foam would work well. Also I looked briefly at the reviews and that’s what a lot of people are doing. Putting it behind the factory mats on the interior foot wells in addition should keep down on heat and sound.


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[HETvet]

Lizard skin. It’s a commercial automotive coating. Get the sound deadening AND heat resistant coatings. It’s 2 separate products from the same company. Total thickness of both materials (heat shield over sound barrier) is about 1/4 inch thick. If it was my personal project/vehicle, I would pull the cab off and coat the fire wall and complete under side of the body. It’s amazing stuff and works better than any other sound deadening and/or heat shielding product I’ve use on the market.

 

[erasedhammer]

Lizard skin. It’s a commercial automotive coating. Get the sound deadening AND heat resistant coatings. It’s 2 separate products from the same company. Total thickness of both materials (heat shield over sound barrier) is about 1/4 inch thick. If it was my personal project/vehicle, I would pull the cab off and coat the fire wall and complete under side of the body. It’s amazing stuff and works better than any other sound deadening and/or heat shielding product I’ve use on the market.

Yeah that's what I initially kinda did with the boom mat spray on insulation. Got a good coating but no where as good as the original NA doghouse rubber.

 

[Carrera911]

It has been a while since I looked at the 6.5 turbo setup when I was considering it. (I decided if I hassle with another motor it’ll be a 12 valve Cummins) Anyway, I remember the up pipe from the manifold to the center mount turbo comes around the back up against the dog house. I would put some fiberglass heat wrap on it to cut down on the radiated heat that soaks into the dog house. It’s cheap stuff and it couldn’t hurt.


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[HETvet]

Trust me when I say this, boom mat and lizard skin are not even in the same ball park. To apply lizard skin, it has to be mixed to the consistency of peanut butter and has to be sprayed out of a professional spray gun. The sound deadening coating is a rubber based coating with fibrous insulation materials in it. The heat shield coating is a sylicone based with ceramic particles impregnated in it.

 

[erasedhammer]

It has been a while since I looked at the 6.5 turbo setup when I was considering it. (I decided if I hassle with another motor it’ll be a 12 valve Cummins) Anyway, I remember the up pipe from the manifold to the center mount turbo comes around the back up against the dog house. I would put some fiberglass heat wrap on it to cut down on the radiated heat that soaks into the dog house. It’s cheap stuff and it couldn’t hurt.


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Yeah I have some wrap laying around. The heat shield seems to be doing a good job.
But heat isn't my problem, it's just the noise. It's stupid the engine sounds the same standing outside the vehicle with the hood open as it does when sitting inside.

 

[Skrilex]

Seems odd that it would be that much louder at idle. Are you sure you have the cover and any penetrations sealed tight?

 

[erasedhammer]

Seems odd that it would be that much louder at idle. Are you sure you have the cover and any penetrations sealed tight?

It's a brand new doghouse. New gasket.
Problem the turbo doghouse uses no high mass insulators. Just a reflective heat barrier and the fiberglass the cover itself is made of.
The NA doghouse has that thick mass loaded insulation.

 

[ryanruck]

Trust me when I say this, boom mat and lizard skin are not even in the same ball park. To apply lizard skin, it has to be mixed to the consistency of peanut butter and has to be sprayed out of a professional spray gun. The sound deadening coating is a rubber based coating with fibrous insulation materials in it. The heat shield coating is a sylicone based with ceramic particles impregnated in it.

HETvet is right. The Lizard Skin sound deadener is awesome stuff!

I did a before and after video when I applied it to my tub.

Before:

https://www.youtube.com/watch?v=dBGARKXE3rI


After:

https://www.youtube.com/watch?v=ywt26Qxef54


I did both the Lizard Skin sound deadener and thermal insulation, FYI. Both are topped with Monstaliner bed liner.

Also, I would recommend taking a look at some of the insulation offered by db Engineering. They are, I believe, the OEM for the HMMWV factory floor mats (or it's at least identical to it).

I don't have any direct experience with an application of their insulation but, I am planning on installing some at some point. One product they have is insulation with a layer of butyl rubber inlaid.

If you don't see what you want for sale online, call them. I bought some of their X-135 trim for weatherstripping around my door openings and had to call them to order it (it fits perfect around the door openings by the way, we'll see how well it seals this winter when I put the doors and top on).

 

[Action]

I just have thd factory doghouse and have s quiet ride. Did you just cut the opening bigger and put the new doghouse on? Some dont put the lip back on the tunnel, and that may be a gap for sound to come in. Are all 6 clamps on thd doghpuse tight? Is thr gasket torn up?

 

[Sintorion]

Any concern with trapping heat by putting the extra insulation on?