howl from my turbo
 

i drive an 02 s4, in california so it has all the smog and etc. was on the freeway at about 65mph, dropped into 3rd from 6th ( not too smart ) and the engine let out a howl which lasted through all the gears upto 6th again, and continued for 30 seconds or so after coming off of the hard acceleration. the performance hasnt really been affected, and have never heard it again but havent really wanted to push her again like that. was wondering if anyone has any ideas on what it was or a similar experience. my only excuse is the kid in the civic with a drain pipe exhaust learned a valuable lesson, and possibly me too. bugger! many thanks in advance. english pool guy.