Originally Posted by Ceadderman
For best results, throughout the setup.
So since you're talking about exterior mounted fans
Yes the Rad is open surface but it will help keep flow moving in one direction and not get eddied.
Okay now I know that last part is confusing. "Eddied" he says w.t.h.
Think of air like water. It's only two molecules different really so apply the dynamics of a river or stream to your flow. The more objects that are in the way of the flow the more water pools and stagnates. This same principle applies to air. If you add surface for air to grip to it will. It won't be as pronounced as water but you'll create undue vortex in the system if the air has a chance to build up. More vortex means less flow. Adding silencers seals the gaps as much as possible without filling the vanes of the Radiator which would now be the only weak point in the unit. But we don't mind this because the vanes are what keep the liquid cooling to return to the pump.
OK, I know this is getting redundant, and I get exactly what you are saying, so in a quest to make it as sealed as possible, it might be better for me to do it this way:
Please bear with me. With having to put at least the one Kaze on the outside of my case for space reasons, I plan on cutting the back of my Antec 900 so it's a gaping hole instead of the honeycomb that is there now. So, thinking the Rad will be right up against this in the inside of the case, it might not be a great seal. Putting the shroud on the inside like my diagram above shows, makes me think I have it sealed pretty tight. Maybe it's overkill, but like I said this is new to me, and if I am going to order fans and stuff, I'd rather order it all in one shot, rather than have to order more things later. Also, I plan on attaching an aluminum filter to the external Kaze, IF I wind up keeping it as intake as I have it now. However, if exhaust with Kaze's will yield better results than my current fans on intake, I won't need the filter.
Thanks a lot Ceadder, you've been a great help!