The fan's exhaust/intake is not reversable. In other words you can't make it pull air through the 4" duct.
I suppose you could push air through a scrubber using the 4". However this would be inefficient for one reason:
Negative pressure is always more efficent and more powerful than positive pressure.
This is a simple law of physics. Same concept goes for a "passive intake".
Now in cases where someone has an extremely powerful fan, (like an Inline, squirel cage fan, or blower) the fan is usually extremely loud, then I can see why someone would want to "push" the air through a scrubber: Becuase "pushing" air through a scrubber will tax it's CFM greater than "pulling", therefor the fan runs quieter *due to efficiency loss.*
Over all its always more efficent to use the laws of nature and just create a negative pressure which is constantly being replaced...Opposed to trying to remove the air by pushing it out. Remember: Passive Intake-
*the scrubber uses the same concpet*
The dimensions and specifications for each fan is linked on the last page aswell. Here is the same link:
Take a look at the link above. They have many models for each line of fans. The line I am using goes up to 380cfm. There are many who grow with a 400-430 watt HID, take a look at the size they are using, im sure the link will provide the panasonic equivilent. If a single fan is too loud, then why not use two quieter fans that add up to the same CFM? If I was growing with a 430HPS in my bedroom, I would probably buy 3-4 whisper fans at a very very low CFM, opposed to one large, noisy whisper fan. Either way, the amount you pay $ for CFM is almost the same when purchasing a single large Vortex with large can filter, or multiple whisperfans with cheap DIY scrubbers. Perhaps you spend a *tad* bit more, but hey, imagine a 430 watt stealth cabinet feet from your bed! No Hydro Store sells that kind of technology yet!