Dynamat on firewall?
 

Considering peeking under the car and seeing what kind of firewall surface behind the engine might benefit from some Dynamat* for sound deadening.

Much easier to access than the interior. Surface far dirtier, will have to be cleaned. Dynamat is safe up to 300+ degrees so fire is a low risk, but because the butyl could soften I won't be putting any near or above the exhaust hardware.

Thoughts?

*Noico, actually. Knockoff Dynamat. Still quite effective IMO :D

I would pass. Butyl product reduces the panel resonance but doesn't block sound from what I've read. Some newer cars put silencer pads on the inside of the firewall. It's probably more of a 3M thinsulate fiber type material than buytl based. And not all the butyl products perform the same over a period of time. Some can drip or separate from the foil if mounted horizontally. Talk about messy! In my experience the Dynamat, although pricier does have a good vertical holding strength. Could also check out the Dynaliner foam products for something that's easy to install and remove. I've used that over the door plastic vapor barriers for a minor upgrade.

3M noise pads - not sure if this is buytl based
https://www.3m.com/3M/en_US/company-...3193969&rt=rud
Paint on option - no worries about sticky stuff
https://www.3m.com/3M/en_US/company-...3241345&rt=rud
Install on inside of firewall
https://www.3m.com/3M/en_US/company-...2659042&rt=rud

It would be far easier to stuff some deadening material in the dash cavities.