I just changed the belt on my vortech supercharger and it squeals when you floor it. I got the truck with a badly worn belt on there and that one squealed too. I thought the new one would help. It doesn't matter if I loosen it or if the belt is tensioned all the way down, it still squeals when you get on it. Thoughts?
I'd check the pulley alignment first; using a straight edge to see if the front of the crank pulley is even with the front of the blower pulley.
Are you sure it's not coming from the accessory drive belt?
also, if all checks out ok, if not using, switch to Goodyear Gatorback belt
if ok there, visit a real hardwrae store, this is a "stick" that is used to rub on the wood surfaces of door jambs to address weather-induced sticking/squeeks....it is not a lubricant but it works well on squeeky belts and does not cause any damage like the "belt dressings" and other "anti squeek belt sprays" do.