a question for my friend

my friend got a 93 gsx about 2 weeks or so ago, and when he went to change the oil, he accidently put too much in...maybe like 1/2qt too much. he's really not too experienced with cars and i told him i'd do it, but he didn't want me too...anyway he went for a drive after changing the oil and a few miles down the road, he noticed a weird sound under the hood...then he noticed it got louder when he accelerated. well it eventually got so loud and obnoxious that he pulled it over, parked it and called for a ride home...he got it towed home like 2 days later...anyway he says that when he was driving, it sounded like mexicans under the hood with machine guns and when he accelerated it got louder, but his car wouldn't really go any faster, but the boost would climb. the only things that are done to this car is a 16g turbo upgrade and upgraded rotors...he started his car so i could listen and it sounds HORRIBLE. i don't think having a 1/2qt too much oil would cause a problem like this... it sounds like somethin in there is hitting something it shouldn't...anyone know what could be the problem?

thanks for any help guys

Is it seem like a knocking sound? My car was (and still is) making a f*cking horrible noise, the bearings in the alternator are goin bad. But be a tad bit more specific and id be more than happy to help.