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I am the owner of a 2021 R7 with the Volvo Penta 380 engine. Does anybody have a solution to reduce engine noise coming from the compartment? Has anybody tried insulating the firewall and hatch, if so what is it effective? Anything else people have tried?

Thanks

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Have you tried dynamat ?

AsLan7 wrote: Tue May 03, 2022 6:27 pm .
Have you tried dynamat ?

X2 or x4

Big Block Power wrote: Wed May 04, 2022 7:01 am

AsLan7 wrote: Tue May 03, 2022 6:27 pm .
Have you tried dynamat ?

X2 or x4

Doesn't it depend on what type of noise the OP is trying to reduce? The Dynamat Extreme says it reduces noise from "structural vibration". In my experience the engine compartment noise is from the combustion/exhaust (manifold) manifold noise which is a different thing? maybe DynaPad is a better product?

I wonder about heat management though if you add too much thick insulating pad to the engine compartment. Is there enough airflow through that space to carry away engine heat as you are effectively further insulating the compartment to hold sound (and heat) in.

BobRae99 wrote: Wed May 04, 2022 11:58 am

Big Block Power wrote: Wed May 04, 2022 7:01 am

AsLan7 wrote: Tue May 03, 2022 6:27 pm .
Have you tried dynamat ?

X2 or x4

Doesn't it depend on what type of noise the OP is trying to reduce? The Dynamat Extreme says it reduces noise from "structural vibration". In my experience the engine compartment noise is from the combustion/exhaust (manifold) manifold noise which is a different thing? maybe DynaPad is a better product?

I wonder about heat management though if you add too much thick insulating pad to the engine compartment. Is there enough airflow through that space to carry away engine heat as you are effectively further insulating the compartment to hold sound (and heat) in.

Dyno mat is thin rubber like material with a aluminum type backing to reflect heat. Plus it's not that hot in there anyways.
The only noise you will still hear is Tuscany bitching. You can't get rid of that

Thanks for the replies, I expect this noise is from combustion/exhaust rather than vibration.

BobRae99 wrote: Wed May 04, 2022 11:58 am

Big Block Power wrote: Wed May 04, 2022 7:01 am

AsLan7 wrote: Tue May 03, 2022 6:27 pm .
Have you tried dynamat ?

X2 or x4

Doesn't it depend on what type of noise the OP is trying to reduce? The Dynamat Extreme says it reduces noise from "structural vibration". In my experience the engine compartment noise is from the combustion/exhaust (manifold) manifold noise which is a different thing? maybe DynaPad is a better product?

I wonder about heat management though if you add too much thick insulating pad to the engine compartment. Is there enough airflow through that space to carry away engine heat as you are effectively further insulating the compartment to hold sound (and heat) in.

Sound is "deadened" by density, that Dynamat is a heavy dense material for its thickness which will help prevent sound transfer. I just wonder with the environment that it is in and that it is hanging vs laying, how long it will stick up there?

As for heat I think it could be beneficial to the life of the upholstery above it. The engine itself has always been cooled by the external water. Like BBP mentioned a boats engine compartment is rather cool compared to any other engine bay

dustinm wrote: Wed May 04, 2022 3:08 pm

BobRae99 wrote: Wed May 04, 2022 11:58 am

Big Block Power wrote: Wed May 04, 2022 7:01 am

X2 or x4

Doesn't it depend on what type of noise the OP is trying to reduce? The Dynamat Extreme says it reduces noise from "structural vibration". In my experience the engine compartment noise is from the combustion/exhaust (manifold) manifold noise which is a different thing? maybe DynaPad is a better product?

I wonder about heat management though if you add too much thick insulating pad to the engine compartment. Is there enough airflow through that space to carry away engine heat as you are effectively further insulating the compartment to hold sound (and heat) in.

Sound is "deadened" by density, that Dynamat is a heavy dense material for its thickness which will help prevent sound transfer. I just wonder with the environment that it is in and that it is hanging vs laying, how long it will stick up there?

As for heat I think it could be beneficial to the life of the upholstery above it. The engine itself has always been cooled by the external water. Like BBP mentioned a boats engine compartment is rather cool compared to any other engine bay

We use this stuff on UTV's and it's not coming off real easy. It will stick. Automotive uses it sparingly all over to deaden noises from road noise to in the trunk. Just in case your hiding someone or something in there

Bob makes a good point here - Dynamat is great at stopping things from vibrating, like the metal shell of a car for example. Foam and other such materials will absorb airborne sound waves and stop them from reflecting off hard surfaces or deflecting hard surfaces, and therefore serves a somewhat different purpose. I've used Dynamat (or an equivalent) to quiet the whole interior of a car passenger compartment down, with added foam behind speaker locations in doors or panels, for example, to absorb sound coming from the rear of installed speakers.

A company called Parts Express makes a nice variety of such materials for the hobby speaker building and car audio markets, something like:

https://www.parts-express.com/Sonic-Bar ... ll-268-044
for the rubberized Dynamat-like vibration damping,

https://www.parts-express.com/Acoustic- ... am-260-318
for standalone foam to absorb airborne waves (need a spray adhesive like 3M 90 to attach it), or

https://www.parts-express.com/Sonic-Bar ... 24-260-535
for a bit of both in the same package (designed originally for speaker boxes). I've used this with the sonic barrier rubberized sheets with good results.

John

John I agree with you 100% if being inside an enclosure with the engine, that foam or the like will greatly help with noise reduction there, but this is being transmitted thru the engine cover itself which needs "density" to stop the transfer, also since space is an issue. For example John Deere used a thin layer of lead in their sound deadening package of the Soundguard cab they used from '73-92 on their 4xxx series tractors steering cowl as they had a hyd steering motor inside that cowl.

Did you find a solution to your noisy engine box?

What did you use and how much did it reduce the noise?

Thanks

Mike

I never added insulation, I believe most of the noise is combustion and exhaust. The rear hatch already has sound absorbing material, so I am not sure adding more will provide any benefit.