blu

So I'm interested in installing an ebay FMIC, specifically a CXRacing kit and am thinking about the 28"x5.5"x2.5" core (2" in/outlet) with 2" piping. I've read all about ideal setups using the 2.5" piping and even 2" hot pipe and 2.5" cold. However, I don't see the reasoning of changing the size...