High pitch squeal

when my cars in neutral and i rev it i hear a loud high pitch squeal , the only aftermarket thing i have on my car is the cat back but have any of you guy ever experinced this?

that is exactly what is it. Just tighten them. I is probbley the lower belt.

Clutch Fan

Remove it or get a new one, check out the fan removal how-to on 240sx.org

http://www.240sx.org/links/installs/efans/index.html

alright thanks guys