[SOLVED] Would 2 of these fans be a good exhaust?

[CraigsCraig]

Hello!
I'm searching for a couple fans for an exhaust on top of my case. So far my choice is https://www.fractal-design.com/products/fans/dynamic/dynamic-x2-gp-14/white/ . Should I be any worried about pressure in the case as I haven't got much knowledge about that? My case is a Deep Cool Matrexx 50. Currently I'm using the default case fan on the back as exhaust and I'm also using 2 fans on the front for intake and one on top for exhaust from this 3 fan pack https://www.thermaltake.com/pure-14-argb-sync-radiator-fan-tt-premium-edition-3-fan-pack.html . The plan is fitting 2 of the fractal design ones on top and moving the current top fan to the the front.
Thanks in advance!

 

[Phaaze88]

Avoid placing a top exhaust fan 'in front of' your cpu cooler, as it serves to draw cool air out of the PC before it can feed the cooler.
Aside from that, I don't see any problem with the planned fan setup.

 

[CraigsCraig]

Avoid placing a top exhaust fan 'in front of' your cpu cooler, as it serves to draw cool air out of the PC before it can feed the cooler.
Aside from that, I don't see any problem with the planned fan setup.

How would I place the fans on top without them being directly above the cpu cooler? Also is it that bad as that way they can draw the warmth from the heatsink. Thanks for the reply btw

 

[Phaaze88]

Hmm, I should've worded that a little differently... picture time!

https://imgur.com/Se03j15

View: https://imgur.com/Se03j15


See how that one fan is 'in front of' the cpu cooler's front fan? You want to avoid that.

 

[CraigsCraig]

Hmm, I should've worded that a little differently... picture time!

https://imgur.com/Se03j15

View: https://imgur.com/Se03j15


See how that one fan is 'in front of' the cpu cooler's front fan? You want to avoid that.

I see. So my current fan setup is totally ok. But that also means I wont be getting 2 but just one of those. But then I'd have 2 exhausts and 3 intakes. Meaning that I'd want to go for maybe around 100cfm instead of the 68 of the fractal design. Right?

 

[madmatt30]

You're better off with more intake than exhaust, generally termed a positive pressure system but isn't really because a lot of case heat is taken away by natural convection through gaps irregardless of exhaust fans.

Although there is much less restriction on exhaust fans than intakes, you can't really compare cfm values between the two.

3 intakes, 2 exhausts I'd term as close to the perfect fan setup.

 

[Phaaze88]

I see. So my current fan setup is totally ok. But that also means I wont be getting 2 but just one of those. But then I'd have 2 exhausts and 3 intakes. Meaning that I'd want to go for maybe around 100cfm instead of the 68 of the fractal design. Right?

If only it were that simple.
Those numbers would only apply in a naked chassis.

 

[CraigsCraig]

You're better off with more intake than exhaust, generally termed a positive pressure system but isn't really because a lot of case heat is taken away by natural convection through gaps irregardless of exhaust fans.

Although there is much less restriction on exhaust fans than intakes, you can't really compare cfm values between the two.

3 intakes, 2 exhausts I'd term as close to the perfect fan setup.

Alright. What cfm should I be looking for then?

 

[Phaaze88]

Alright. What cfm should I be looking for then?

There's a lot more to it than just fan airflow.
-fan rpm
-fan air pressure
-fan noise
-chassis design and fan/radiator options

-the 'obstacles'. The stronger they are, and the more there are = the weaker airflow becomes going through or around them = the harder the fans have to work.
Case exhaust is EZ mode. The resistance is usually just the grille, and the air is up and out of the chassis.

The intakes, on the other hand:
-solid front panel and fan proximity
-air has to turn upon entering the chassis
-filters(if present)
-psu shrouds
-cable clutter(if present)
-HDD cages(if present)


[Mount the front fans on the opposite side of the fan bracket if possible. They'll be a little farther from the front glass, and have more breathing room to draw in air.

 

[CraigsCraig]

There's a lot more to it than just fan airflow.
-fan rpm
-fan air pressure
-fan noise
-chassis design and fan/radiator options

-the 'obstacles'. The stronger they are, and the more there are = the weaker airflow becomes going through or around them = the harder the fans have to work.
Case exhaust is EZ mode. The resistance is usually just the grille, and the air is up and out of the chassis.

The intakes, on the other hand:
-solid front panel and fan proximity
-air has to turn upon entering the chassis
-filters(if present)
-psu shrouds
-cable clutter(if present)
-HDD cages(if present)


[Mount the front fans on the opposite side of the fan bracket if possible. They'll be a little farther from the front glass, and have more breathing room to draw in air.

I have thought about that but the rgb would get covered up and stuff. Would look kinda sketchy. I've thought about buying a mesh separately and mounting it in the place of the glass if possible. Can that be done and would it cover up the rgb too much? Also if I have 3 fans with 70 cfm but bottlenecked by the glass, how much cfm would I need to counter it? Ofc cfm isn't the only thing that matters but it plays a big role when I need to know what to look for.

 

[Phaaze88]

I have thought about that but the rgb would get covered up and stuff. Would look kinda sketchy.

Looks... of course. I can't do anything about that one. That's your call.

I've thought about buying a mesh separately and mounting it in the place of the glass if possible. Can that be done and would it cover up the rgb too much?

It's certainly doable. Have you ever done a chassis DIY project before?
I've done it with my H500P Mesh's acrylic top panel:

https://imgur.com/PecrXb1

View: https://imgur.com/PecrXb1

https://imgur.com/QSCmlHp

View: https://imgur.com/QSCmlHp


You can have your RGB and good airflow if done right:
Corsair iCUE 220T RGB Airflow - the front panel design isn't to everyone's tastes...
Cooler Master MasterCase H500 - mesh
Corsair iCUE 465X RGB - the glass is positioned away from the chassis a little, instead of being almost flush with the fans
Phanteks Eclipse P400A Digital - mesh
Corsair Crystal 570X RGB - same as the iCUE 465X above

Also if I have 3 fans with 70 cfm but bottlenecked by the glass, how much cfm would I need to counter it? Ofc cfm isn't the only thing that matters but it plays a big role when I need to know what to look for.

You need an aerodynamic engineer for that kind of math... and I'm not one of those.

 

[CraigsCraig]

Looks... of course. I can't do anything about that one. That's your call.


It's certainly doable. Have you ever done a chassis DIY project before?
I've done it with my H500P Mesh's acrylic top panel:

https://imgur.com/PecrXb1

View: https://imgur.com/PecrXb1

https://imgur.com/QSCmlHp

View: https://imgur.com/QSCmlHp


You can have your RGB and good airflow if done right:
Corsair iCUE 220T RGB Airflow - the front panel design isn't to everyone's tastes...
Cooler Master MasterCase H500 - mesh
Corsair iCUE 465X RGB - the glass is positioned away from the chassis a little, instead of being almost flush with the fans
Phanteks Eclipse P400A Digital - mesh
Corsair Crystal 570X RGB - same as the iCUE 465X above


You need an aerodynamic engineer for that kind of math... and I'm not one of those.

Thanks for all the info. Having all of this in mind, I think that my first goal is fitting a mesh instead of the glass. Is it possible that I unscrew the glass somehow and then slap a bought mesh in its place? Also I haven't got any intent in buying a new case. I also believe that rgb is still easy to see even if behind a mesh. I havent had any other DIY projects like this.

 

[Phaaze88]

I don't see any screws, so the glass is attached using either glue, or some other adhesive, around the edges.
That would then mean having to use a heat gun or hair dryer to loosen the adhesive's grip in order to remove it.

 

[CraigsCraig]

I don't see any screws, so the glass is attached using either glue, or some other adhesive, around the edges.
That would then mean having to use a heat gun or hair dryer to loosen the adhesive's grip in order to remove it.

I will look around in person but if it hasn't got any screws, I'll most probably stay with the glass. Thank you so much for taking your time to help me.