Airflow question

I would draw a pic if i knew a way to get it hosted, but anyway here is the problem:

Later this summer i am going to add a 172mm Cormair Rotron Major as the intake for my Cheiftec Dragon case (mid tower) running at 7v. At the moment i have 2 80mm exhaust fans, both vantec stealth.

What i am alost planning to do is add a second fan to my psu in the back (i have seen the mod around). I also wanted to add a 120mm Panaflow LA1 as a blowhole. I would like to know if the two fans which will be right next to each other will cause problems for the airflow in my case.

My goal with these fans is to prevent positive pressure from building up in my case and run everything at 7v for a moderate noise reduciton

the solution 4 hosting:
www.theforumisdown.com

post the pic to thread,
and let me see...

The two black boxes with the white in them are the fans i am going to add, and want to know if two outake fans so close teogether are going to cause a problem

i edit your diagram!

this is the new diagram,
as you can see, better 4 your cpu...

Hard telling not knowing.

Airflow control is tricky and even the OEMs experiment with different configurations; simply adding another pci card can wreck a great airflow pattern!!

Adding a fan to the psu as an intake temporarily can be done without any mods: use cable ties to hold it on

If the top panel on your case is removable you can use cardboard as a temporary panel to test the blowhole fan placement.

If you have enough intake ventilation in the case then both new exhaust fans should be fine, but running negative pressure may make those two fans compete for flow. Your psu should still be better off though as you will be forcing air into it with one of the new fans, and that would be my worry with the blowhole on top and negative ventilation.

I would say that the modified edition would work fine. Is that heater core for a water cooling system? If so I would move it to the back of the case so you don't have the heat recycling through the CPU. What you may also consider to balance it out is putting another 120mm fan blowing out from the bottom or even sucking in.

Thank You,
Daniel

Oh yeh i forgot to mention that i am building a water cooling setup . In light of that i really don't think that air slightly warmer rushing past the water block is going to make a huge difference in my cpu temp.

Also i like the idea of placing a fan at the bottom of my psu, however there is a huge circuit board blocking that .

If i have to choose i think i will just have a blowhole at the top unless i find some really good way of modding the psu.

And i might leave a second intake fan blowing some air across my hdd rack. I think/hope the combination of all these fans will maintain a favorable airflow balance.

Thanks for the help so far!

i edit it again!

if u sacrifice your first cdrom bay, this diagram r best 4 u!

My airflow works like the second pic, with air coming in the lower front and exiting through my case top, power supply, and rear case except I have no heater core. This way the air is coming in, cooling my hard drives, then being sucked over the CPU and out either the rear of the case, the top, or the PSU. It keeps a constant flow of cooler air going over my CPU fan, which in turn blows cooler air on my CPU. In my case my CPU stays cooler than my case temp by about 2-3 degrees except under load.

By the way does anyone know the noise of the Rotron on 7v or even 12? I was thinking of putting one of those fans as an intake since one was for sale here.

Depends on whether it is a 12 or 24 volt version- mine are 24v.

At 12 volts they are about equivalent to the 120mm Enermax variable speed fan I have: loud but not too obtrusive. We don't have to turn up the tv volume to drown them out
At 10.5 volts or so (lowest they will run) they are even quieter and still flow an impressive amount of air.

I am not quite as happy with them as I thought I would be, but they are certainly good enough that I haven't done anything aout replacing them

err... forgot to mention that also, i have the 12v version attached to a voltage switch and i can tone it down to 7v. It is custom made, so all of the fans in my case will be hooked up to it sooner or later.

:edit: I am probobly gonna go with the second setup assuming i can make it work, thanks for all the help!