I installed my forge dv recently and when i first went to start it up, there was a loud high pitched whining sound coming from the area of the dv. I connected the ends of dv correctly and it is tight enough. It seems to go away when the engine is warm and the revs sit under 1k. Does any1 have any suggestions

 

Did you forget to reconnect the secondary air injection hoses, or maybe break one during the install? The secondary air pump and hoses run in that general area.

 

If his car is a manual I don;t think he has a secondary air pump... Would have been my first guess too though.