question on venting out air.

I have a 435 cfm fan sitting on the top of my 4x2 tent. The entry and exit ports on it are 6 inches. I have regular 6 inch ducting connecting it to the hid fixture, but to push the air out I used a 6-to-4 inch port reducer, basically so I could run several yards of ducting out to my window. The question is: does shrinking the size of the ducting in this way adversely affect its ability to push out air? It's still hotter than I want in this tent. I'm wondering if I need a slightly stronger fan.

Also, been thinking of taking it off the tent and setting it on the floor, covering it with a box (to help with noise). That way there's more equal amounts of ducting on both sides of the fan. Or does that even matter?

Yes, 4" duct flows much less than 6" especially on a long run.

Run 6" duct and if you MUST then reduce it at the window.

Personally, I wouldn't worry about it. If that tent is 4x2x5', it's only 100 sq ft- the fan will still perform well. As long as you're pulling more air out than is being circulated in, you have negative pressure and odor is under control.

+1 to Snaps, though. It would be more efficient to not constrict the airflow. You might even be able to turn the fan down if it has adjustability and will save you some electricity.

Moving the blower closer to the window, using 6" duct, would increase the cfm some, at the expense of increased blower noise outside.