I appreciate the response but I have a engine stethescope and its not the engine. This noise is coming from the supercharger and if I remove the air box cover you can here it clearly its coming from the supercharger and I belive it the rotor bearings are failing and with the scope you can hear the grinding at the rotor bearing end of the SC I just replaced the coupler not more than a month ago and I used GM supercharger oil.