case fans

[travenwatts]

i am getting ready to buy some better case fans and i was wondering if it was neccessary to put the same fan in the front chassis and rear chassis.

right now i have a fron chassis fan at @30cfm and a rear fan that came with the case. it isn't very good because not much air is being exhausted out.

i am looking at replacing both fans but putting a bigger rear fan. i will have to drill new screw holes, but that is not a problem. i am looking at this one:

Delta 120x120x38mm Fan (ABF1212LE)
http://www.coolerguys.com/Merchant2/merchant.mv?Screen=PROD&Store_Code=001&Product_Code=F-D120&Category_Code=F-120

for the front i plan on using an 80mm fan becaus that is the size of mount i have. any ideas? i want good airflow iwith minimal noise. if i need to sacrifice noise for better airflow i will.

[Drak55]

Radio Shack might have that same fan a bit cheaper I just installed one on mine lastnight I payed $11.00 for it same spec's

[stool]

Check out Panaflos. They offer a choice of 3 different fan speeds with varying noise levels.
http://www.coolcases.com/cart/p120_1a_2_u.html

[travenwatts]

so does it not matter whether i have a more powerful fan in back than in front?

[looktall]

some would say yes, some would say no.

i say yes.

i prefer to have roughly the same amount of air coming into the case as going out. a balanced air flow.
some prefer negative (more out than in) and some prefer positive (more in than out.)

by putting the 120mm fan at the back blowing out (assuming it has a larger cfm rating than the 80mm fan) it will create a negative air pressure in the case and suck dust in through all the gaps and cracks in the case.

ever pulled apart an old pc and found a thick layer of dust between and around the cdroms. that's from negative air pressure sucking air into the case.

having a positive air pressure prevents the dust being sucked in through the gaps and cracks.

IMO opinion, having a balanced airflow allows for more effective use of the air by the hsf.

but really, the best method is the method that works best for you.

[travenwatts]

thanks looktall...

so i guess i will just put two of those delta 120mm's. i will have to mod the front too but shouldn't be a problem.

if you see a problem in doing it this way please let me know. i am open to criticism

[looktall]

two of those deltas are going to make a lot of noise at full speed.
i'd suggest putting them on a switch, so you can run them at 7v, or even turn them off, when you don't need them. like in winter, or at night when it's cooler.

making a 120mm blowhole isn't too hard. i haven't been coming to these forums for too long, but i'm sure there would be a how-to in the case modding forum.
if there is one, i don't know if it mentions it but a cd is exactly the right size for marking out the hole for a 120mm fan.

of course you could just go for 80mm fans at both ends. i'd still go with making a blowhole though. no point putting in a fan if you're going to block most of its airflow with a case. lol