So I'm just starting the build on my own dream computer. It's going to be going to college with me next year (im a senior in HS) so i went with a regular mid tower. usually i would prefer a full tower, but i have to think about dorm space and transportation. I got myself a Lian li pc 65 in black, i think it looks amazing. (i am a bit of a lian li fanboy though...i cant get enough lian li...)

So My question refers to fan placement and what direction they should go.
Heres a pic of the case:


So as you can see, its got two intakes on the front. These are a little weak because they go through that front panel and a filter behind. It has one fan on the back there, but i found room for another right below that i'll cut a hole for. And it does have a blowhole, but i will be cutting it away to replace it with a 120mm blowhole.

Now how i see the directions is the two front fans as intakes and then the two back fans and the blowhole as exahaust.

now, is that too much exahaust? should i get some more air going in? and if so, from where? if it would really help i could do a side panel thing, but personally i hate those. they look bad imo.

Oh and another related question: can the pressure/air turbulence inside the case effect the noise coming out? if so, what would be the quietest configuration? (assuming you use the same fans, which set up would make the turbulence the least or whatever?

Thanks for any advice

::BUMP:: for the evening crowd...i know the cooling forum isnt really browsed too much (ive never really studied up on this air flow stuff)

Off the top of my head...

Using the two front fans for intake, adding a second fan in the rear for exhaust creates an internal equilibrium... To add a 92 or 120 top exhaust blowhole would "for best results" require another intake fan of equal(ish) CFM. Where you put it is up to you, since you said you hate side intakes...

As for the noise factor, replacing the stock fans with some quieter ones would do about the best for noise reduction, since just about any fan is going to make noise, be it used as an intake or exhaust. Personally, though, it seems that the exhaust fans should be making the most noise, as they would "blow" the noise out into the room... It's late, so if I'm not making any sort of sense, I apologize...

An ATX configuration is usually in from the bottom front and out through the top behind the CPU.

I recommend replacing the left door with a box fan, and remove the right door and replace it with modder's mesh. That will greatly increase your airflow.

I'll give a try at helping you out with your questions in reverse order; it will make more sense that way. A fan under stress will be fighting to create airflow, causing an increase in noise. Using a near equal amount of airflow will lower the amount of stress to the fans, lowering the noise.

However, equal intake and exhaust does not have to be achieved by using fans. Enlarging/creating new holes in the case will reduce the restrictions to the exhaust fans. Proper placement of the fans and perhaps the addition of ducts can put the airflow right where you want it. Also, don't forget to account for the PSU fan. With it being situated near the top of the case, it is a good candidate for a fan upgrade to help exhaust heat from the case.

There are as many ways to set up the fans as there are modders to install them, and many people will swear their way is best. I have seen alot of good set-ups, and as long as it works for you, then that is all that matters. You could probably get away with two lower CFM fans in the existing 'exhaust' spots, with the PSU exhausting as well. Then put some higher CFM fans in front for the two intake fans.

If you add the second exhaust fan to the rear and widen the top blowhole, then increasing the airflow coming in would really put that extra exhaust to good use. There are other options than using a fan in the window. You can add a PCI slot cooler. There are several options for increasing airflow from unused 5 1/4 bays. I personally like to cut a hole in the right side panel near the bottom front of the case and stuff a fan between that side panel and the mobo tray.

The vented area over the PCI slots could be opened up and perhaps fitted with a home made high flow filter. I could go on and on, but I think you got the idea. Greatly increasing the airflow in only one direction probably wont give noticeably better results than what you are starting out with. Increasing the intake and exhaust ports together should work better. Generally in a tower case the airflow follows convection principles and exhausts at the top.

With proper ducting and enough effort, you can make the air go wherever you want. Base your cooling mods on the machine. How far do you plan on taking the rig as far as OCing? What will this rig be mainly used for, homework or gaming? I hope these ideas help.

Thanks Wrath, great stuff

I had an idea though...what about a bottom intake? it would end up being pretty much directly beneath the blow hole. would this work okay? or interfere too much with the horizontal airflow?

turbulance is your best bet in internal airflow, so don't care what kinda smoothness you get outta it

the mesh for equalizing airflow is a good option preferablly with a filter of sort

Wrath summed up a good bit but no one really said this, the fanbeside te CPU on the back should always be intake, for the reason of the CPU cooler (if air) can then getthe freshest outside air it can, which ive gone through multiple test for this and i just cant see it any other way nor have i seen resultswith the exhaust beside the CPU fan. I think lian li makes a PSU exhaust duct fordiverting the hot air up so your intake below it wont pull any hott airin again as well

the top hole is prime real esate for exhaust fans moving the most heat outside the case, and the front is bst for pulling the coolest airinside the case

thevented PCI slots isa good idea IMO never thought of it, i always turn them into fan blowholes for the extra fan on my not so many PCI card PCs

silence isnt my territory i dont give a crud, its noisy or not it dont make a difference to me