First time I put the fan dead center side to side, IF I install on new OBS, I may put it to one side, in attempt to get air to swirl in circler motion.
Thoughts?
I think putting it in the center would be fine. The air would hit the door and then swirl around both directions to the back, not just one. That's where I plan on installing mine.
What fan model did you get and what cfm blade are you going to use? Mine is this one: Granger item # 4M079 (http://www.grainger.com/Grainger/wwg/search.shtml?searchQuery=4M079&op=search&Ntt=4M079&N=0&sst=subset) - $44.50, 1.65 lbs, 2" shaft length, 1/70 HP
I have a 2 1/2-inch blade for a 45cfm airflow. I can easily swap it for a 2-inch blade with a 30cfm airflow if I find there's too much turbulence with the larger one.
If you use the type of fan blade common in the fan addition mod you will find that the air flow is largely out at ~ 45° from the motor shaft axis. That's why the shield was added to prevent blowing hot air directly on any meat on the rack immediately above. It's mostly blowing air outward up-left-right-down, and comparatively little straight out along the shaft axis. That really stirs things up well, and I doubt you will get any more swirling by moving it off center.