E30 Zone

i'm pretty sure my e30 track car is going to fail some of the more stringent noise tests at various tracks.

the exhaust has a Powerflow exhaust backbox with 6x4 round tailpipe - (see pic) which would make it difficult to stick a coke can over the end. not sure i could get one inside, and get it to stay there!
http://i36.photobucket.com/albums/e9/po ... 010854.jpg

I am also concerned about the general induction noise when accelerating. if i build a heatshield round the cone filter (see pic) would this help at all.
http://i36.photobucket.com/albums/e9/po ... 010855.jpg

i found this old thread and there was mention of putting cardboard round the filter, but am a bit worried this would not be very secure?
http://www.e30zone.net/modules.php?name ... aust+noise

any suggestions welcome on either route......

I can't see a 325i having problems, E30 M3's with C/F airboxes and after market exhausts make so much more and get on UK tracks.

well i was at Bedford last week and luckily the bloke was not watching the rev needle while he had the sound meter at the back. he told me to rev it to 3/4 and hold it.
we had a couple of goes before i got it to 3500 without him looking at the revs and i told him that was 3/4 and he passed it !
but before i held it at 3500 it went to 4300 and afterwards he told me he had it bouncing around a 106db .....i won't get on anywhere with that and a more picky sound meter attendant !!!

Its dependant on the trackday. Circuits are only allowed so many 'loud' days a year and these are normally for big race events.

I personally don't think induction noise should be a problem,

If your worried just put a standard system back on (stainless exhaust release very little power) or replace the back box with something that can be 'packed'

Hiya All ......... for your general information ......... I did a track day at Donington today in my E30 325i and the car passed the test which was a 98 decibel "drive by" test. Perhaps because it is a rally car, they had noted my car as one that looked like it might be noisy and tested it several times.

My car has a standard exhaust manifold, standard front pipes and front muffler. I cut the large standard rear box out and replaced it with another front box (much smaller {lighter} and also makes getting the mounting rubbers on and off easier). It now has two similar boxes that are both "straight thru" which gives it a nicer sound, maybe flows better ??, and passes the test !!

I have a standard inlet system (my ITG panel filter didn't arrive in time ) and the engine is standard but with a chip.

Donington is supposed to be one of the toughest on the noise testing so I should now be sweet at any other venue.