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Old 10-28-2008, 07:15 PM   #16
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easier test, open your computer, then see if the fan on the heatsink for the processor blows or sucks

it blows, if you don't want to do the test
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Old 10-28-2008, 07:38 PM   #17
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Why?




Ok thanks for all the input guys but i will still test this with my new lrp heat sink and the 40x40 fan
The GAYTE.
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Old 10-28-2008, 08:07 PM   #18
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This sounds like a line from Space Balls..."She's switched from suck to blow!"
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Old 10-28-2008, 09:11 PM   #19
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actually on the computer side that is half right. while the fan on the processors blow down on the heatsink the fan in the powersupply sucks the air out of the case. so all in all aside from the low pressure cool high pressure hot laws you want to remove the heat from the location and the heat that the motor of the fan builds up away from the heatsink. the suck property also applies to GFX chargers the fan on the back of mine sucks air in from the side and blows it out the back. airflow pushed into a confined area is likely to build up heat pockets rather then airflow that is sucked from the same location. think of it this way the fan that you blow at yourself if you placed it 1" off your body would you not be cooler quicker as it removed hot air from you. the only reason you point a fan at you is the convenence of not having it attached to you.....
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Old 10-28-2008, 09:24 PM   #20
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if i was good enough to have any fans, i wouldn't mind if they sucked or blew..
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Old 10-28-2008, 09:40 PM   #21
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Have you ever considered using two fans? One "sucking" off the top of the heatsink and one blowing onto the side. Therefore it not only pushes more air to cool it but it also cycles air over the entire ESC and heatsink faster. I havent done this but have been thinking about it for quite some time now. And if you have holes drilled in the side of your esc like my MM then that will make it cool off the insides even faster!!! But in essence.... One forces cool air onto the ESC, one pulls all the hot air away, and the one blowing will also help force the hot air through the one pulling air away
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Old 10-28-2008, 10:34 PM   #22
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Just thought i would chime in tha subject.

Look at fans in cars, many have electric ones that reside behind the radiator. the reason for thrm sucking air rather than blowing is that the heat build up in the tight space can cause the fan just to spin and NOT blow any air though. but placing it where the heat is extracted into cooler air that the molecules are not pressing back as they are trying to get away from the radiator.

Thus the most efficient way of doing it pullingit away not pushing it on.

Can't look at the fan on the person as that is perception, there is no fan should around the person so sucking around the person isnt going to feel the same as different air being pressed on the person, thus the perception is that blowing air onto is a better idea.

Anyway in rc cars (and computers) the temp on heat sinks typically doesnt get as hot as cars and there is not much of a fan shroud around them, but efficiency wise sucking it better than blowing
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Old 10-28-2008, 10:43 PM   #23
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Only problem I see with that is that air is forced through the radiator then the fans just help force it away. And on your ESC, with all of the groves and such on the heatsink there is no presure build up that stops the fan from blowing.
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Old 10-28-2008, 11:06 PM   #24
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for me, i will choose blowing.....

since so many opinion bout blowing and sucking....
the easy and effective way to prove which is d best is by testing the both method and measure the temperature after 5minutes.....

Blowing = Celsius
sucking = Celsius
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Old 10-29-2008, 01:13 AM   #25
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Quote:
Originally Posted by streetracer745 View Post
Have you ever considered using two fans?
Yes......I had a cooling set up for my nimhs like that

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Originally Posted by nashrcracer View Post
actually on the computer side that is half right. while the fan on the processors blow down on the heatsink the fan in the powersupply sucks the air out of the case. so all in all aside from the low pressure cool high pressure hot laws you want to remove the heat from the location and the heat that the motor of the fan builds up away from the heatsink. the suck property also applies to GFX chargers the fan on the back of mine sucks air in from the side and blows it out the back. airflow pushed into a confined area is likely to build up heat pockets rather then airflow that is sucked from the same location. think of it this way the fan that you blow at yourself if you placed it 1" off your body would you not be cooler quicker as it removed hot air from you. the only reason you point a fan at you is the convenence of not having it attached to you.....
Yes on my mm power supply they suck, on my pulsar 3s they suck, on my pc power supply it sucks and the fan in the front of my case sucks

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Originally Posted by mxzhonkey View Post
Anyway in rc cars (and computers) the temp on heat sinks typically doesnt get as hot as cars and there is not much of a fan shroud around them, but efficiency wise sucking it better than blowing
Yes that is what i was thinking........And so does my dad but hey he only works on pcs that cost more than ferraris

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for me, i will choose blowing.....

since so many opinion bout blowing and sucking....
the easy and effective way to prove which is d best is by testing the both method and measure the temperature after 5minutes.....

Blowing = Celsius
sucking = Celsius
I will be doing that in a moving car and in a stationary car
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Old 10-29-2008, 04:22 AM   #26
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"Suck or blow" has been tested with CPU heatsinks before, way back in the old celeron 300A days. Blowing wins
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Old 10-29-2008, 05:43 AM   #27
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sucking draws air from everywhere fairly evenly (pc case etc) while blowing directs the airflow more directly onto a target which thins out the microscopic layer of air that sticks to everything and acts like an insulator. The faster the air over a surface the thinner that layer gets, so a well directed fan on a target beats sucking. If you have multiple targets like in a power supply you have to suck....
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Old 10-29-2008, 05:56 AM   #28
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I tested this last years and found that blowing was more effective.
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Old 10-29-2008, 06:02 AM   #29
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this has to be the best thread of the month
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Old 10-29-2008, 06:03 AM   #30
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hi guys , while we are here and i dont want to creat another thread , does blowing air onto a cell increases its IR , cause i got a muchmore battery heat sink and the 6 fans are sucking not blowing air towards the cells so i was wondering if i could change the fans direction to blow iar towards the cell but i dont know if it will increase the cells IR ?
Thanks
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