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This is gonna be an ongoing thread as I want to include both the hood and the cab.
My general plan is a thin underlay followed by something thicker.
For the hood, I also plan on doing the firewall, at least with the thinner layer. Then a thicker hood liner
I did a bit of searching on the web and did not find any actual studies where someone compared one brand to the other using any sort of instrumentation , every review I found was based on the reviewer's ear. I decided to go with Dynamat because every review said it was the best. Every review also said it was the most expensive.
I didn't do a starting decibel because I didn't think of it, but even if I did it would be tainted because I've made other sound improvements beyond stock.
So, before any sound insulation I have a D turbo, an 18" Donaldson muffler and my stack is 11' high.
Probably the cleanest the underside of the hood has been since it rolled off the assembly line
So, I used just under 6 sheets of Dynamat Extreme. Each sheet is 4 sq/ft and .067" thick. I used a good pair of 10" heavy duty scissors and a framing square to make rough cut outs. I also had a rolling tool (they're cheap). I would guess that the under side of the hood is really close to 22 sq/ft. I overlapped a little bit here and there. A bulk box of Dynamat is 36 sq/ft, I'll probably use most of the rest on the firewall.
This stuff is also .45 lbs per sq. ft., so, I added over 10 lbs to the hood and it is noticeably heavier. I will be adding a handle to the hood, not totally necessary, but I just think it's a good idea. The hood liner is about half the weight of the thinner stuff.
I did do a decibel test after the above pic. It's 102 decibels from about 10 feet in front of the engine, and 104 decibels in the cab. I'm using a freeware decibel meter app on my phone, so I can't say how accurate it is, but hopefully it'll at least be consistent. It did seem to me that some of the high notes were mellowed out - more deep rumble, which is one thing sound protection is known for.
Next step is the hood liner. I'll try to get to that in the next week.
My general plan is a thin underlay followed by something thicker.
For the hood, I also plan on doing the firewall, at least with the thinner layer. Then a thicker hood liner
I did a bit of searching on the web and did not find any actual studies where someone compared one brand to the other using any sort of instrumentation , every review I found was based on the reviewer's ear. I decided to go with Dynamat because every review said it was the best. Every review also said it was the most expensive.
I didn't do a starting decibel because I didn't think of it, but even if I did it would be tainted because I've made other sound improvements beyond stock.
So, before any sound insulation I have a D turbo, an 18" Donaldson muffler and my stack is 11' high.
Probably the cleanest the underside of the hood has been since it rolled off the assembly line
So, I used just under 6 sheets of Dynamat Extreme. Each sheet is 4 sq/ft and .067" thick. I used a good pair of 10" heavy duty scissors and a framing square to make rough cut outs. I also had a rolling tool (they're cheap). I would guess that the under side of the hood is really close to 22 sq/ft. I overlapped a little bit here and there. A bulk box of Dynamat is 36 sq/ft, I'll probably use most of the rest on the firewall.
This stuff is also .45 lbs per sq. ft., so, I added over 10 lbs to the hood and it is noticeably heavier. I will be adding a handle to the hood, not totally necessary, but I just think it's a good idea. The hood liner is about half the weight of the thinner stuff.
I did do a decibel test after the above pic. It's 102 decibels from about 10 feet in front of the engine, and 104 decibels in the cab. I'm using a freeware decibel meter app on my phone, so I can't say how accurate it is, but hopefully it'll at least be consistent. It did seem to me that some of the high notes were mellowed out - more deep rumble, which is one thing sound protection is known for.
Next step is the hood liner. I'll try to get to that in the next week.