Which case pressure in Fractal Design Nano S?

[TheMajesticBurger]

I am going to build my first custom loop in summer, and it will be inside the Fractal Design Nano S. I will have two 240mm radiator with 2 SP120mm, one on top and one on front. I will have the front fans be intake, but I don't know about the rest. I can also put one AF120mm fan in the back. So should I have the top radiator fans be intake? Since I have heard negative pressure is bad, but I can't really make it neutral.

 

[the nerd 389]

If you're not using a pump mounted to the bottom of the case, you can put another intake there.

That way, you'll have 2 front intakes, 1 bottom intake, and 2 top exhausts.

If that doesn't work, then you can always adjust the fan curves for neutral/positive pressure. I certainly wouldn't advise using the top radiator as an intake.

If you want to tune the fan curves, I'd be happy to walk you through it. It takes some time and patience to do correctly, though.

 

[TheMajesticBurger]

If you're not using a pump mounted to the bottom of the case, you can put another intake there.

That way, you'll have 2 front intakes, 1 bottom intake, and 2 top exhausts.

If that doesn't work, then you can always adjust the fan curves for neutral/positive pressure. I certainly wouldn't advise using the top radiator as an intake.

If you want to tune the fan curves, I'd be happy to walk you through it. It takes some time and patience to do correctly, though.

What are fan Curves, is it when the fan speeds are put higher than others?

 

[Karadjgne]

A fan curve is the relationship of fan speed to temp. Default normally is @<40°C- 60% fan speed to >70°C - 100%fan speed, so in that curve, at 50°C, you should be seeing the fans run at @75% of their rated speed. This can be adjusted in your bios, so that you have less or more range, if you set the duty cycle for 50°C, then at <40°-60%, and at >50°-100%, so without much change in temps, your fans will spin much faster, much sooner.

Pressure isn't all that relevant, nominal being 14.7lbs/sq.in, what you'll get inside a case is 14.7001lbs/sq.in positive to 14.6999lbs/sq.in negative. It's honestly just enough to either repel or attract microparticulate dust. There's just too many gaps in a case for air to enter/escape to maintain any real pressure difference.

So that only really leaves you with airflow and heat. The cpu won't be an issue, but the gpu(s) will be, so you'll need decent top exhaust of some sort just for that. With one rad in front as intake, that'll dump heat into the case, so combined you'd be looking at a little more just to cover rad/gpu heat as exhaust. The inclusion of the 120mm at rear exhaust plus the top 240mm rad as exhaust, will be sufficient. I'd not put both 240mm rads as intake as this'll double the volume of hot air inside the case. Better to use the rad top mount and dump all that heat directly outside the case, while doing double duty as exhaust fans.

 

[the nerd 389]

As stated above in a rather lengthy manner, fan curves are the relationship between the temperature of a component and the speed of the fan. Usually, the CPU temperature is the one used to control the fans.

The trick with otherwise unbalanced fan setups is getting mild positive pressure at all variations of fan speeds. It takes work to pull that off.