Put room between radiator and fans? or not? fan efficiency

hey guys,
to start i really should start sleeping...

but thats not my question.
I-am still working on my modded car radiator (for in pc use)
But i have a question concerning the fan mounting.

i have bought 6 Cooler master ultra silent 120 fans (really crappy but only 10,-)
and i wonder if i should mount them directly on the radiator, leaving no room for air to flow underneath the motor and all.
or maybe rise it 2mm or so (with a wooden board with 120mm holes in it between fans and rad) so the air has more vins to go trough (underneath motor).
and do that for every fan apart, or 3 fans togheter (3 fans on one hole in spacer) or all 6 fans (with one big hole in spacer between rad and fans)

i ask this because the fans are really low pressure.
so what would be smart?
directly on the rad, or leave some room between the rad and the fans?

i really don't know how these dynamics will work.
please enlighten me.

The closer the better. When firing a gun what hurts more being a mile away or point blank range?

If the fans are really low-pressure, they should be as close to the radiators as possible. It might even be a good idea to duck tape the sides to prevent air from going in directions other than directly through the radiator.

also, in case you're not aware, if your car radiator is made from aluminum (as most are) it's important to use aluminum throughout your loop because mixing Aluminum and copper will cause galvanic corrosion.


Here's a quick video that goes over fan shrouds: https://www.youtube.com/watch?v=MYbG-uv4Op4

Edit: Another good source http://martinsliquidlab.i4memory.com/Radiator-Fan-Orientation-And-Shroud-Testing-Review.html

10 fans @12v in close proximity to one another is going to move a lot of air regardless of static pressure rating. With your thin (I'd say 5mm at the very most) board be sure to make a tight seal around the outside (silicone, foam gasket, etc) You dont want any air pressure to escape between the radiator and your fan board.
And as EllisD mentioned be very careful with the rest of your loop construction the last thing you want is corrosion in your nice shiny waterblocks. I think Phobya still sell their massive radiators (120.9) may be worth a look if you run into trouble.

okay so..
i should be using a shroud thats right, right?
and it is better to make all the fans blow trough one big shroud?

i know ;) but my whole loop is aluminum so there is no problem there.
check here https://forum.teksyndicate.com/t/car-radiator-for-pc-non-conventional-rad-for-pc/75333

i-am quite sure thats not how it works.
its more like, the bullet needs to speed up in a barrel so would you use a short or a long barrel?

What i think he is discussing is shrounds.. in the case of most aios and radiators nowadays they already have a bit of a standoff so the shroud is unnecessary... Also go get a bunch of EK Vardars.. you will not be dissapointed :D

hahaha if you could give me some :P
note that i bought all 6 (actually i bought 7) together for 10,- euro's and ONE vardar costs 15,- euro's.......

30 dollars difference for amazingness just saying :P

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well 6 times 15 is 90,- euro's..
that would be a 80 dollar difference.
however if i ever get enough money for a nice pc i'd really buy some vardars.
note that all 6 fans will go on the rad

well yeah but i was speaking before any purchase.. so the difference between 6*10 and 6*15 is 30

i don't think you get it.
i paid 6*1,66 if i get vardars i'll pay 6*15 so the difference is 80

From what I am reading you purchase 6 for 10euros... from what I am reading up there.. and the others are 15?

vardars cost 15,- EURO's a piece