I don't mind the noise on full chat but the drone it makes while cruising at motorway speeds is annoying to say the least. Have been looking at why you can hear so much of the exhaust note inside the car and ways to damp down the drone.I never knew it until I started the wire tuck mod on my car but in each corner of the boot there's an open path from the boot space running between the inner rear wheel arch and engine bay that leads directly to the area behind the trim panel where the rear speakers are mounted.
There are no bulkheads along this path to absord the sound, just a little bit of foam behind the rear trim panel and a thin bit of factory sound deadening material on the back of the trim panel. Given where the exhaust tips are located, inches below the boot skin, I think the boot is amplifying the exhaust note and that sound is travelling down the recess directly to the cabin. The minimal sound deadening in this area is doing little to damp down the exhaust note and after researching sound deadening foam I've concluded the stock soft foam is the wrong type for sound absorbtion or deadening.I got some high density foam, which apparantly has better sound blocking properties than soft foam, and crammed as much as possible in the area behind the rear trim panels.
My car is still a few weeks away from being back on the road but fingers crossed these measures will go some way to reducing the exhaust drone if not eliminating it completely. Will let you know if it has helped once I'm back on the road but if anybody wants to give this a go in the meantime I'd be very interested in hearing the results.This is the stuff I used.
http://www.ebay.co.uk/itm/ws/eBayISAPI. ... true&rt=nc
I bought 2 blocks but only needed just over half a block to do both sides.
If anybody else wants to give this a try you can have the spare for the price of the postage. There should be more than enough to do both sides.You can see in this picture where the foam was installed.
