Originally Posted by Eleventeen
I honestly don't think it's the supercharger itself. It is the design of the SC clutch. When the clutch engages, there is a split second of slip that occurs. This momentary slip between two pieces of steel being engaged causes the high pitched sound you're hearing. I guess it can be compared to the squeal that metallic brake pads cause on the rotor. I honestly believe the clutch would have to be redesigned to eliminate this annoyance; many people experience this issue with these engines. I've read of people replacing the SC clutch or entire SC to remedy this, but it is just a waste of time and money as far as I'm concerned. Once the clutch wears in, I guarantee the sound will return.
My SLK32 has 25K miles and it has never squealed that way...the SC engages a lot (even when my foot's not in it), but I never hear slipping squeal, with or without the Code 3 pulley that I installed about a 800 miles ago. I would tend to agree that the supercharger is not the issue. Maybe shimming the clutch plate closer will help; or if the clutch has a lot of miles, maybe refacing it would help (if that's even an option).