I pulled the cog belt and turned it by hand and it sounded like it was scraping. Next step, like you said it to visually inspect it.

 

with your current pulley setup these are your s/c speeds.

engine rpm 7000rpm. supercharger rotor speed = 56,550.88 = BAD

engine rpm 6600rpm. supercharger rotor speed = 53,319.40 = GOOD

your current pulley set up is good! but dont rev the engine past 6600 rpm. as you can see above anything past that and you are over speeding the supercharger. from my experiance you can over speed the blower a little bit and make boost without damaging the blower. Im sure you know but the max rotor speed for your V-2 SQ IS 53,000.0 RPM.

 

53k is what vortech says is the max rpms, and that's what they rate their parts being able to handle, but you can still probably spin it more if you're willing to risk the blower needing a rebuild at a much quicker rate

especially for people who don't need the Z to be their daily driver and drive it just a few times a week.
Besides, it'll only overspin the blower for the short amount of time that you're redlining the car

 

it might be a fueling issue! i noticed on your sig you have 440 injectors. but is it still a returnless fuel system or other wise stock with bigger injectors and pump. from my own experiance when i was going up in boost levels with different pulley arrangements my tuner at the time said the same thing. we were running out of duty cycle on the injectors and had no more fuel for the engine. i installed a cjm stage 1 return fuel sytem, rc 550 injectors and walboro 255lph fuel pump. never had a problem with fuel again. with the pulley arrangment you have obviously you want to make increased boost and power. i suggest a return fuel system upgrade and try the 440 injectors. but be ready to purchase at least 550's.

 

yes i already know this. I did the calculation using the vortech impeller speed calc before I purchased the pulley. I might as well do the SI upgrade like you, since I have to send it in for repair anyway.

 

cool thanks for the info. At this point I think it will be easier and cheaper in the long run if I just do 750cc and RFS, I'm thinking just the AAM basic for ~$500

 

sounds good! good luck.......