Engine compartment insulation/sound

[lipets]

Time to replace it, what have you used that worked well, I don't so much care about heat it stays good with ventilation.

But want to cut the sound a bit.

The black foam that's in there is about 1.5", no foil.

Suggestions?

 

[Comodave]

I put in Soundown 2” 2 pound per square foot. It has a PSA backing and a vinyl loaded barrier in the middle. It has the PSA backing but I still used the pins to help hold it on.

 

[fgarriso]

Soundown makes a good product, I would contact them first.

 

[Keysdisease]

Foam absorbs noise, it is not a noise barrier. In Como Dave's post he describes "2lb per sq ft" which is the mass barrier in that insulation product. Mass is a noise barrier, in this case what's called Mass Loaded Vinyl (MLV) a very common lead replacement product.

Imagine a wall between you and another person made of paper, now imagine the same wall being concrete block, which works better to block voices?

The reason the foam failed is acoustic foam is open celled, to perform better at absorbing noise. It also absorbs engine space vapors which are often acidic and cause the foam to fail. That's why most acoustic foam has a vapor barrier face. Add a barrier like what Como Dave used and you get an absorber and a barrier (and a decoupler) which enhances the performance of the product.

Even more important is various leaks, like hatch gaskets and air paths that may intrude into accommodation spaces. If the vents that bring air to the engine are above the deck, this might be worthy of treating with insulation

$00.02

 

[Mischief Managed]

Another vote for Soundown. Works great. Use an electric knife to cut it, much easier than a box cutter or any other knife.