same as me to get it to flutter louder you need to go to efi mate, for some reason efi i so much louder. i take it you have no dump valve cause that will stop the flutter plus a big ass induction kit will help. the noise itself is the air from your turbo forcing its way back through your induction kit hense why a dump valve is not good for the noise. wish tehre was a cheaper way thou there was a fiesta trb at engine advantages when i was getting a set up and that flutterd fukin loud!!!!!