Noise reduction foam for bonnet

[gm44]

I'm thinking of lining my 2017 S3 360R bonnet to help reduce noise as I was very close to the limit at Brands on the static test; suspiciously close as I'm normallly about 96/97db and the car doesn't sound like it's become any noisier in the last few weeks. The only difference I can think of is that the Brands test area is surrounded by walls, but I can't see how that could account for a 4db difference.

My car has the standard exhaust, silencer, cat and airbox, all of which appear to be in good condition.  I'd rather avoid the cost of a Raceco silencer.

Has anyone tried this and if so can you recommend a product?

Regards Gerard

[Amos91]

I can't imagine that will make any notable difference when you're using the standard airbox. 

The noise is all in the exhaust and that's where you'd need to look at reducing if necessary. 

What revs did you have to hold that? I'd have thought 96db area as you say would be normal. 

[gm44]

5,500 which is the normal level, I'm hoping there was something wrong with their noise meter, but preparng for the worst.  I'm at Bedford next Monday with LoT where the limit is again 101db.

[Geoff Brown]

The plan to line the bonnet will in all probability raise under bonnet temperatures to a questionable point ?

In high ambient temperatures with just a 'tin' bonnet it can rise to 120C > in the engine compartment. Extra 'insulation' could start to cook areas that would normally be resistant ?

 

[Golf Juliet Tango]

Wrong target, I doubt it will reduce noise levels, which are primarily induction and exhaust.

[anthonym]

" a 4db difference"

Silencer packing is fried?

"Wrong target, I doubt it will reduce noise levels, which are primarily induction and exhaust."

Agreed.