Doghouse insulation - tell me why this won't work

[plfking]

After searching threads on this subject, the consensus seems to be that Dynamat or similar won't hang upside-down very well, or at all.

Could I remove the old foam/fiber/batting, layer Dynamat to the same thickness, then secure it with hurricane straps bent to match the inner curve and bolted into place? I'm not worried about the bolt nuts being visible in the cab, as I'll have cabinetry hiding the doghouse.

Would there be a problem with a bolt head possibly resting against the turbo pipe, or against the rear of the engine? And would the Dynamat need a covering of header tape or similar?

(bike added for scale)

Thanks for any advice or suggestions.


Don

[Robin97396]

I don't remember anybody being real happy with insulating the inside of the doghouse, either for sound proofing or heat issues.

The folks that seem happy built a cover for over the doghouse. You can have cup holders this way.

[cadillackid]

I dynamatted the doghouse on my DT360. and the flat plate on my T-444E. and the result is i have just as much heat as I had nefore and not much less noise..

on the DT I had issues with the dynamat coming down from the heat...

im with robin I thinking making a doghouse cover if you still have clearance for your feet is the way to go... you can insulate it for heat and noise..
Dynamatting the inside of the footwells on the bus makes a little noise improvement but zero heat improvement..

-Christopher

[Tango]

About the only positive feedback I have heard on Dynamat was from hot rodders who used it on previously bare sheetmetal. They claimed some noise reduction (when every square inch was covered $$$). Never heard of anyone satisfied with its' heat reduction.

Sound reduction requires mass. As in a pound or more per sq. ft. Sheet lead is toxic but still the best there is.

Heat reduction requires thermal reflectivity...absorbtion...and/or a thermal break. Think Shuttle Tiles and the way they are installed.

[plfking]

Thanks for the input guys. Will demolish this drawing board, and go back to my old one.


Don

[cadillackid]

Originally Posted by Tango

About the only positive feedback I have heard on Dynamat was from hot rodders who used it on previously bare sheetmetal. They claimed some noise reduction (when every square inch was covered $$$). Never heard of anyone satisfied with its' heat reduction.

Sound reduction requires mass. As in a pound or more per sq. ft. Sheet lead is toxic but still the best there is.

Heat reduction requires thermal reflectivity...absorbtion...and/or a thermal break. Think Shuttle Tiles and the way they are installed.

if I took the carpet out of a car for a Build I dynamatted the whole floor and footwells.. it made a surprising difference in the amount of road noise.. I always installed or updated the A/C so i didnt care about the heat

[jjhwick119]

Are you using regular sound deadening dynamat? Might have better luck with the under hood dynamat stuff for insulating doghouse. Regular dynamat will hang upside down, I was a 12v installer at car toys for decade, and have done more roofs than I can count, and with good prep never had an issue with it staying on metal surfaces (regular dynamat)

[cadillackid]

Originally Posted by jjhwick119

Are you using regular sound deadening dynamat? Might have better luck with the under hood dynamat stuff for insulating doghouse. Regular dynamat will hang upside down, I was a 12v installer at car toys for decade, and have done more roofs than I can count, and with good prep never had an issue with it staying on metal surfaces (regular dynamat)

i think the issue is that the doghouses are plastic.. at least mine is..

[jjhwick119]

Gotcha...that makes more sense.

[tailor]

Would using foil backed under hood felt work?

[Tango]

The foil over felt helps some, more with heat than noise. But make sure whatever metal the felt backs up to is well protected. The felt holds moisture like...well, felt.

[Jolly Roger bus 223]

For this discussion maybe we need to start discussing.
how much heat an engine puts off.
For the ones with the turbo close to that cover that heat is a lot more.
I don't know mine but know I have to address the issue but am planning on doing it on the inside of my straight forward metal cover with the same access still available.
But I have access to hight temp ceramic fibre,fire blanket scraps from my work when building duct off of kitchen exhaust hoods. It is foil wrapped and encapsulated at each cut with the proper tape.
Isn't cheap stuff. But I get leftovers.
But I think an engine temp. Discussion and turbo temp discussion should be involved in deciding an insulation to be under hood and next to engine.
We can assume that it is taken into account when figuring it out but some material has a specific distance away from certain high range temps in an under hood application.
Not saying the stuff won't work but if the stuff falls down on the engine or even higher temp turbo? Will it light up?

[Tango]

Heat proximity is indeed a big deal. An air gap, especially if it is moving air, will make a huge difference in the heat transmitted to the doghouse. My turbo and downpipe are inches away from a steel doghouse which has the potential for cooking a side of beef. One way to reduce the heat transfer is to shield or isolate the heat source.



On my shorty I had the downpipe ceramic coated inside & out...then wrapped it with the volcanic tape...then put radiant heat shields over the whole thing (with an air gap between the shield and pipe). On the turbo, I used a full wrap blanket. As much to help performance as reduce radiated heat (a turbo will spool faster if you can keep the heat in).

Once the doghouse is installed, I will coat it in ceramic paint on both sides...add some radiant foil type shielding on the motor side...and then build an "outer" wooden doghouse inside over the metal with another air gap and noise and heat insulation in between.

That's about all I could come up with on my build.

[Jolly Roger bus 223]

I knew you would be the first?
Some builds are special and I wish I had my own special one.
As you know most are trying to build basics and I think if they know the temps under the hood/doghouse and what's close to it then might look at different insulation Underside the doghouse from the factory verses inside addition that is better protected from the weather.
High radiant temps from the engine and accessories is what needs to be considered before deciding what to type to use.

[plfking]

My cover is plastic also, and was a very tight fit coming off, which makes me think it's resting against something when installed.

What are your collective thoughts about something like this lining the interior of the doghouse, and held in place with the hurricane straps I mentioned earlier? I also like Hybuzz's idea of a hood scoop to direct cool air over the engine then down to the ground....seems like that would help underhood temps considerably.


Don

https://www.amazon.com/Ceramic-Insul...QE8VMKH43633XV

[Tango]

Directing airflow over the hotspots will definitely make a difference. I am looking at a dedicated electric fan to do just that myself.

[PDXTom]

How did your dog house cover work? We’re trying to reduce engine noise in our flat front, front end diesel Blue Bird.
Can you post pictures? Anyone else?
Thanks!

Originally Posted by Tango

Heat proximity is indeed a big deal. An air gap, especially if it is moving air, will make a huge difference in the heat transmitted to the doghouse. My turbo and downpipe are inches away from a steel doghouse which has the potential for cooking a side of beef. One way to reduce the heat transfer is to shield or isolate the heat source.



On my shorty I had the downpipe ceramic coated inside & out...then wrapped it with the volcanic tape...then put radiant heat shields over the whole thing (with an air gap between the shield and pipe). On the turbo, I used a full wrap blanket. As much to help performance as reduce radiated heat (a turbo will spool faster if you can keep the heat in).

Once the doghouse is installed, I will coat it in ceramic paint on both sides...add some radiant foil type shielding on the motor side...and then build an "outer" wooden doghouse inside over the metal with another air gap and noise and heat insulation in between.

That's about all I could come up with on my build.

[Jolly Roger bus 223]

sorry
we lost TANGO last year.
he is in a better place.
please research the forum or start a new thread?

[RolesvilleMarina]

I wish I had my skoolie when he was still around..

Someone on my thread said I reminded them of him. I had to go back and read up his threads... amazing bloke.

I'm here to try and pick up the slack then.

But it was queer indeed that I am working on this exact project on our Vista and lo and behold do I not see a thread titled "doghouse insulation"

I ended up using that somewhat flame retardant house panel stuff.
and some scrap wood to use as "washers"



the actual doghouse is mad of fiberglass, and has the standard layer of foam and then the rubberized coating.

I covered the house stuff with rubber roofing material I had lying around and came out like this.



Important to note, as Tango point out some doghouses are mad close to hot things. I lucked out again in the vista that under the dog house I have enough room to house an actual dog I would think. I'm a good 10 inches plus from any hot items. There is also plenty of airflow. It's a huge space.

I also have two spare "holes" in the front bumper that I could also use with some kind of 8-10 piping and force air right on my turbo to cool it or just into the space... but I don't think I will need this. The doghouse never really got excessively hot before.

I did this mostly to try to cut down on the noise as much as I can. Swapping out the AT545 helped a lot, so anything more is a bonus.

Also I ended up build this lunch/drink console. It hinges up and the plan was to store towels or spare blankets in there will even further muffle any noise.



then lastly will be to install some more carpet of some kind from the unfinished trim in the photo down to the bottom on the dog house. But the missus has not picked/found what she wants to use yet.



Very pleased so far

bonus points to anyone can figure out what the brass round thing is.

Hint: was in a movie

[PDXTom]

Originally Posted by Jolly Roger bus 223

sorry
we lost TANGO last year.
he is in a better place.
please research the forum or start a new thread?

I am sorry to hear that. He sounds like a very good man. Thanks for letting me know, and thanks to everyone else for the helpful information.

- Tom