i have a 2003 audi a4 1.8t 5speed. i was driving my car pretty hard on a windy road when i heard this bumping/grinding noise comming from underneath my cabin. it only does it hight rpms and peak boost and from a roll around 2000 rpms in first gear. i can hear the bumping when i go over bumps or something which lead me to belive it was my tranny mounts. id have more info but i dont want to drive it and cause more problems. also when i first heard it i pulled over and popped the hood and my manifold and turbo were read hot. i dont know if thats just because its running lean or me driving it hard or what. probally nothing to do with my problem but its something i noticed. at first i pulled out the coils and put them back in. the car runs fine at idle and i dont hear the noise reving it when im parked. so i beleive its drivetrain or something. im running stock boost and i have an intake exhaust and dv and suspension. from a roll i hear the sound around 2k and goes away after 2.5k or when i let off. if i get on the throttle i hear the same noise when im on the cams at like 3.5k but when i let off the gas it goes away. its only when im on boost i think.
also i have another minor problem. i hear grinding noise comming from my clutch area when im driving in wet or cold conditions. almost sounds like grinding and wont go away until i come to a complete stop like metal vibrating agaist metal. it happens from time to time and its not allways making that sound in those conditions. maby water getting into my cluch or something? i dont smell my cluch burnin up when i hear it. ty

 

lol... i don't think any grinding sound is a minor problem...

it seems like you have alot going on there... i can't pass any judgement w/o being able to see it for myself. nothing is a problem i have really heard of in relation to the problems your having.

clogged exhaust, running lean, oil or coolant issues w/ the turbo....

clutch chatter, torsion springs, warped disc... water on the clutch... if you were somehow getting water on the clutch and it sit... it could rust and cause it scrape of grind until the rust was worn off... i dunno