so, driving the other day i hear what usually sounds like crickets at night here in FL, only this is day time... so, i roll the window down and it gets much louder. Then i shift, and notice it rises / falls with certain RPMs.

i am willing to bet dollars and donuts, that something on the supercharger is going / gone... Water pump? or bearing(s)? anyone have any input as to what sounds their SC's made when they started to crap out?

i still have full power, and the car doesnt overheat... but, for how long?

 

It could be something so simple as the idler pulley or belt trensioner. Rig up a makeshift "stethoscope" with a length of tubing or a long piece of dowel rod held to your ear. While the engine is at idle, place it on or near various components until you localize it, then verify by getting someone to raise and lower engine speed while you listen. Be careful of moving parts while you do!

 

If you haven't done this, do a rev on neutral to eliminate the the rest of the drivetrain. if its still there then you might be right or something in the engine.

 

i can almost guarantee its not those you listed, as my belt tensioner was replaced only a few months ago when the shock blew its guts out all over my engine. golly what a mess!

it sounds like bad gears. only reason i suspect its the water pump, is bc a mini tech showed me a bad supercharger with messed up WP gears. when i turned it, i sounded / felt kinda "crunchy".