Vacuum line left out in every thread.

Hey guys, I was driving around today enjoying my exhaust drone and my thoughts began to ponder about my emissions when suddenly I realized that after like a year when I had changed my vacuum lines to silicone ones. I remembered that one line that runs behind the intake manifold which was torn but I didn't replace because it was bigger than 3mm(or was it 3.5). Any who, that hose as far as I've always seen in threads, has always been left out. Some have asked but never got a response as to what size it was. And now, I'm asking for the bump on this, anyone know the size?? It has clamps of doom and connects to the T fitting. It is about 2.5 inches long.
It is under here:
http://i1362.photobucket.com/albums/r695/evilpulse8/null_zpsa6c8da9a.jpg

and this is the hose:
http://i1362.photobucket.com/albums/r695/evilpulse8/null_zps55f04f1d.jpg

Also as I unplugged a vacuum line from that little zinc plated block(vacuum check valve?), I'm not sure as if air sucked in or blew out. Could it be a sign that it is clogged somewhere?? If one line is torn, it obviously should have no vacuum anywhere what so ever, no???