Johan, See post # 39 here
http://*************/forum/f16/poten...43/index4.html and read in conjunction with the text below. For the ***** substitute ************* to complete the link. It looks naff but certainly works for engine noise and must help for the amount of roar you get from the front.
In hindsight it would have simplified install if the bracing bars had been removed prior to putting the sisalation layers in place.
The layers have slits leading to holes that match various hoses or pipes. The slits of one layer are vertically down, another vertically up, one horizontal and another more or less diagonal. Thus the slits are overlayed by adjacent layers.
The shielding rests below on the transmission housing and 10cm back into the tunnel and blanks off the tunnel. It comes up behind (but not touching) the engine and curves over to rest on the black bracing bars. While driving, It may rise there to contact the bonnet but there are no flapping noises. There is plenty of room for heat to rise and no contact with exhaust below.
The shield curves around horizontally as far as possible and slightly covering the suspension damper turrets.
I tried burning sisalation. The paper backing burns but quickly extinguishes.
I have just tried revving up to the redline in second gear on smooth bitumen. At that low road speed wind and tyre noise is more or less out of the equation i.e. leaving mainly engine & transmission noise.
I am blown away by how effective this sound-shield is. Engine noise at 7000rpm is now very similar to what I hear in everyday driving around 1200rpm in top.
I love it. No longer is it a somewhat tinny car but altogether more refined and there's no loss of fun factor.