1991 V2500 Suburban sound insulation project

[yevgenievich]

Upper door seals kill 70 to 80 % of highway wind noise. They were available in 70's on the squares but were later removed as cost savings(making an assumption on cost savings part). LMC sells new sets, or general 3/4 foam seal can be used instead. Tires are a bit rougher being E range rated. Wanted to ran D range, but tire store was resisting being that I have a 3/4 ton.

 

[yevgenievich]

Behind dash is done, back together and already blower fan does not seem to be as loud on high speed as before. Started to prototype under the dash panels, only passenger side in place out of cardboard. Going to run with card board first using same insulation behind it as a test to deside if I should bother with them.

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[yevgenievich]

The cardboard backed by mlv and closed cell foam is in place under the dash. I hope with other firewall insulation this will not make enough difference to bother with making actual panels. Will drive with it for few weeks and get some readings, then remove them and see if there is much difference.

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[yevgenievich]

I am reaching a point of diminishing returns. I have now additional drop of 8-9dBm . Cruising highway speed is around 54dBm, down from 64db. Close to the 98 e320 wagon. I still can insulate under the hood better and add a quieter muffler, otherwise I have pretty much reached the limits of the body design. Main noise now comes through the door glass and surrounding the door(due to being uncovered metal).

 

[yevgenievich]

Figure to update on the under dash panels. Covered on both sides, decently reduced noise.

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[Camar068]

@yevgenievich Did you put anything directly on the door skins? Mine sound like a 5 gallon metal bucket being dropped when I close the doors lol.

 

[yevgenievich]

@yevgenievich Did you put anything directly on the door skins? Mine sound like a 5 gallon metal bucket being dropped when I close the doors lol.

There were couple of pieces on door skins as well. Doors sounded solid when closing

 

[Camar068]

Thanks

 

[Camar068]

forgot to ask, what thickness did you use? Thanks Again @yevgenievich they've got 1/8" to 1 1/4".

 

[yevgenievich]

forgot to ask, what thickness did you use? Thanks Again @yevgenievich they've got 1/8" to 1 1/4".

Just standard 1/8 should be enough on door skin. At the end the major noise sources I had were through windshield and side glass