Ok I have a PM1300 dust collector that I have setup with an Onida super dust deputy, I have the fan and motor assembly mounted to my wall and the DD mounted directly onto the housing, so I'm not using any other parts of the original dust collector just for clarification. I plan on venting outside now that I'm in the country with no neighbors. I have made an adapter for the exhaust that is 4" ID that will exit out the wall.My DC unit was rated at 1300CFM at 6" and I'm assuming that is measured at the inlet? I'm using 5" ducting for my system right to the machine. So Im curious....... if Im using 4" for the exhaust with no filters am I restricting the performance of the DC?