Intake port size?

i was going to try a DIY cold air intake...i need to know the size of the pipes that they use on manufactured ones such as AEM. I think its 3" (the size of the pipe where it meets the intake manifold port) but i need to be sure.

thanks!

I don't think it's as big as 3", think it's more like 2¼" or 2½". But you shouldn't make the pipe bigger than the throttle body, because there's no point. The amount of air that goes into the engine is only as much as the smallest opening. So for a basic setup, you only have to think about the t-body opening.