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Under bonnet sound insulation upgrade

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In my eternal quest to subdue my N47 at idle I am thinking of doubling up on the under bonnet sound deadening.

 

Removing the existing layer, adding some more adhesive stuff and refitting the original cover.   Cheap enough to do so worth a try,

 

Has anyone ever tried this?

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Point to note, my folks G01 with a B47 lump in 2.0d guise, has no under bonnet insulation.  In the cabin on the move the sound isn't very intrusive at all but outside on idle its not very refined, although a friend of the wife who has an X1 with a 1.8d badged version of the same engine it's really audible on idle, like spanners in a cement mixer.

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9 minutes ago, 535i Andrew said:

Point to note, my folks G01 with a B47 lump in 2.0d guise, has no under bonnet insulation.  In the cabin on the move the sound isn't very intrusive at all but outside on idle its not very refined, although a friend of the wife who has an X1 with a 1.8d badged version of the same engine it's really audible on idle, like spanners in a cement mixer.

Curious that the same engine would sound so different in two different bodyshells. Wonder if the state of tune is anything to do with it, doubtful though.

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On 31/10/2018 at 23:04, 535i Andrew said:

Less fuel makes it sound noiser.

 

 

Same engine capacity and same idle speed (presumably) means the same amount of fuel to keep it ticking over. I'd go with different engine mounts and less insulation rather than less fuel.

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Its a lot to do with injection timings and quantities. These have a real impact on engine noise, etc. They had to introduce a new clutch/flywheel on the old E91 320d's EDs due to the additional vibration from the engine at running at lower consumption. 

Anyway, plenty of info.... 

https://www.dieselnet.com/tech/diesel_fi.php

Edited by SuperDave

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I recall reading in the f10 they have really insulated B47 and mounts are really absorbing, they mention engine is almost cocooned to enhance refinement and aid heat up apparently supposed to retain heat for much longer I presume x1 due to design and chassis can’t seal engine as much

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