Bonnet insulation

Spriteracer · Post by **Spriteracer** » Sat Jan 16, 2021 5:03 pm

Am I correct that there should be no insulation on the underside of the bonnet (hood) on an E86 ? Mine doesn't have any and I can't see any on real oem.

Just about every other car I've had since the 80s has had it.

Thanks.

Weston Matt · Post by **Weston Matt** » Sat Jan 16, 2021 5:35 pm

No there isn’t any. I looked as well. You can if you want add some between the frame.

Spriteracer · Post by **Spriteracer** » Sat Jan 16, 2021 5:54 pm

OK as I won't worry about it then. I have added the dense sound bitumen type insulation in various other places to lessen the drumming, but I don't think it will have much impact on the bonnet. I might add a couple of pieces just in case if I have any left. Many thanks.

blunderthumbs · Post by **blunderthumbs** » Sat Jan 16, 2021 11:22 pm

Exhaust tips 1.jpg

Can't hear any drumming from my Zed due to the throaty exhaust.

DMike · Post by **DMike** » Sun Jan 17, 2021 9:38 am

Spriteracer wrote: ↑Sat Jan 16, 2021 5:54 pm OK as I won't worry about it then. I have added the dense sound bitumen type insulation in various other places to lessen the drumming, but I don't think it will have much impact on the bonnet. I might add a couple of pieces just in case if I have any left. Many thanks.

The bonnet can get quite hot so bitumen might not be optimal - could eventually be harmful if bits fall on the engine, e.g. the belts.

Spriteracer · Post by **Spriteracer** » Sun Jan 17, 2021 10:13 am

DMike wrote: ↑Sun Jan 17, 2021 9:38 am The bonnet can get quite hot so bitumen might not be optimal - could eventually be harmful if bits fall on the engine, e.g. the belts.

Good point ! Thanks.

Chris_D · Post by **Chris_D** » Sun Jan 17, 2021 12:41 pm

Insulating the door panels and maybe even the boot lid are good moves but the bonnet? That’s just weird.

Spriteracer · Post by **Spriteracer** » Sun Jan 17, 2021 1:50 pm

Some manufacturers do some don't. My Volvo XC70 has it, My wife's 123D doesn't. I've had other cars in the past - including early BMWs that did. I think it is mainly noise absorption rather than thermal or anti resonance. Helps to keep the noise emitted to the wider world down. If only someone would invent a silent tyre / road combination.....

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