is there any way to tell if an IC is big enough?? I know w/A2A that bigger is better but you lose boost, with a W2A IC how can you tell if it is big enough to work and not just hold heat??

I am looking at an W2A that measures 4in X 4in X 12in with 3in holes? would that work to cool a procharger? STS? and my favroite a Rotrex

or should I look at a OBX style A2A??
thanks
joe