When the revs of the engine drop there is a weird sound sort of like a metallic rattle/hiss but the phone camera cant seem to pick it up properly but if you turn the volume loud enough you can just about hear it. This same sort of sound comes when the car is going uphill but louder. Instead of making a spooling sound it makes that funny sound but the car still pulls very strong, it was dyno'd and made about 147bhp at AmD. A bit confused but I will try and take another video while driving to pick up the sound under boost as well in the meantime any help would be appreciated. Thanks ASN.