2 rad fans vs 1

[Pntgrd]

I currently am running a Dtek Pro rad with 1 Evercool fan/shroud set in a pull config in the front of my case. The fan is hooked to a Vantec controller and set to 8 or 9 volts, just a little faster than a 7v mod trick. I am thinking of pulling the pump and rad out of my case and building a wooden box or something to put them in. I want to reclaim a pci slot to gain back my Soundblaster soundcard. The onboard sound chip will not let my run the pci.agp at anything above 33/66, or the sound craps out. I have tried modifying a small sink to fit the Southbridge. It is right at the end of the agp slot and the locking lever open s right over the top of the chip so a fan is out of the question. The Soundblaster lets me run at 37/74 locked with no problems. Anyway, if I do this, I was thinking of going to 2 fans in a push/pull config. Does this actually help? I am having trouble working that out in my mind. The single fan pulls a certain amount of air through the rad. If you put another fan pushing air but set to the same speed, there is still the same amount of air going through the fins to cool. Help my dense mind understand HOW this will help. Do you have any data to back it up?

[UberBlue]

Two fans = ablity to pony up greater static pressure (the ability to overcome resistance) = greater net airflow.

Don't need collected data to back it up. It's simple physics.

[Baowuf]

Originally posted by Pntgrd
Anyway, if I do this, I was thinking of going to 2 fans in a push/pull config. Does this actually help? I am having trouble working that out in my mind. The single fan pulls a certain amount of air through the rad. If you put another fan pushing air but set to the same speed, there is still the same amount of air going through the fins to cool. Help my dense mind understand HOW this will help. Do you have any data to back it up?

Let me see if I can tackle this. When you pull (or push) air through a radiator, the air is slowed because it comes in contact with the fins. Your fan is having to work hard (and consequently not as fast) to pull the air through the radiator. If you were to put a pushing fan on the other side, the air would already have a velocity once it hit the radiator, instead of being accelerated from a standstill. This would allow the sucking fan to pull more air though and therefore be more efficient . I personally don't have any data to back this up, but I'm sure there is plenty of people here with two fan setups that can vouch for better performance. Granted they are not all getting 3-5 degree drops, but the upside is that you can undervolt the fans (like you have done already) to get the single fam preformance at a quieter setting.

I hope this was clear.

edit: See Blue's post for the cliff notes version. I'm slow.

[Pntgrd]

What I meant by "data" was experience of anybody that had done it both ways. I guess I used the wrong word. I understand better now, hadn't thought of the pressure aspect. That make sense.