I've just about finished my router table build; a slightly modified version of Norm's design.
I'll be running a 4" line from my cyclone to the router mounting area under the top. I also have a 2 1/2 inch line to the fence. I purchased and had planned to use a 4x4x2.5 wye to split off the line to the fence behind the table. In other words, 4" to the cyclone, 4" to the router dust box, and 2 1/2" to the fence. Problem is the wye is nearly a foot long and will kind of be in the way sticking out of the back of the table. I can live with it, but wondered if I can just run the 2 1/2 line from the fence to another hole in the router mounting box and still get decent suction. The area has a door and is totally enclosed except for space around the bit insert and the makeup air holes. I've sized the makeup air supply holes so the total area--including the area of the 2 1/2 line from the fence-- is about the same as the area of the 4" line.
It seems to me the line to the fence should see roughly the same suction if I just run it into the dust box compared to running it to the wye.
Another option would be to actually run the 2 1/2 hose through the hole in the dust box and position the end right by opening for the 4" line to the cyclone.
Anybody done something similar or just have any better ideas or thoughts about the best approach?