Case fans being choked.

TaintedSquirrel

TaintedSquirrel

[H]F Junkie
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Aug 5, 2013
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I'm running a Define S with 3x140mm in the front.
If I attach the dust filter OR the front panel, it cuts my airflow approx in half with each piece.

Are there any sort of long screws or a mounting bracket I can use to move the fans farther into the case by maybe 2 or 3 inches to clear up their intake?

GPuDH80.png
 
Ocellaris said:
If the filter is that restrictive (which I doubt), spacing the fans isn't going to help.
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Exactly this.... If your fans lose half their effectiveness, and the hand is not the best way to determine flow....a filter (especially one like that) is not lowing the air intake.

Even by moving the fans off the filter , you wont eliminate any barriers, thus the total pressure buildup on the fan is the same, There are methods you could use...maybe the "Silencer" pads for the 120mm fans, with some standoffs would be able to accomplish what you are looking for in the aesthetics side, performance wise you would not see any difference.
 
The difference in airflow with and without the filter is drastic. So yes it's definitely restricting the fans unless its spirits from beyond the grave screwing with me.

Should I tape a piece of yarn to the top of the case to check it?
 
Id be most concerned with the filter off lack of airflow than anything.... You are going from partial airflow to little airflow....What fans are these?
 
Get some high static pressure fans.

Any fan is going to drop some from installing a filter. The question is, is the air flow adequate enough with the filter on?

If the fans are dropping that much from just a filter such that your not able to control temps in the case, they need to be replaced anyway.
 
W.Feather said:
Id be most concerned with the filter off lack of airflow than anything.... You are going from partial airflow to little airflow....What fans are these?
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They're GP-14's, Fractal's 140mm.

Brian_B said:
Get some high static pressure fans..
Click to expand...
Yeah the thought has crossed my mind. Although I'd much rather just find a solution here, even if it means getting creative.

pendragon1 said:
solution = ditch the filter AND get better fans. fuck filters and learn to clean the case!
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Definitely not an option, my house is a dust bowl.
 
fair enough. i just preferred cleaning more often over sacrificing airflow.
just looked at the fan specs; what speed are you running them at? they are supposed to push 68cfm which isn't bad and your vid clip does not look like that much airflow. crank em up and see what happens. otherwise I think Brian is right, youll need high sp fans to pull through the filter.
 
That filter design is shit anyway. They restrict it with an aggressive filter, then add all those cross pieces further adding to the issue.

The fans need replaced, but honestly I don't know if that will help. I have some Gentle Typhoons, and while they help on some filters, they don't help a lot. They seem to be just right for my Lian Li case though.
 
pendragon1 said:
fair enough. i just preferred cleaning more often over sacrificing airflow.
just looked at the fan specs; what speed are you running them at? they are supposed to push 68cfm which isn't bad and your vid clip does not look like that much airflow. crank em up and see what happens. otherwise I think Brian is right, youll need high sp fans to pull through the filter.
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They're running off molex, so full speed (~1000 RPM).
Based on the noise I'm not sure I'll actually run them at full speed regardless.
 
yipes. maybe some SPs then.

edit: those vids are with the front panel off too, right?
 
TaintedSquirrel said:
I'm running a Define S with 3x140mm in the front.
If I attach the dust filter OR the front panel, it cuts my airflow approx in half with each piece.

Are there any sort of long screws or a mounting bracket I can use to move the fans farther into the case by maybe 2 or 3 inches to clear up their intake?
Click to expand...
Get better fans. I suspect those are the stock fans and the Dynamic GP-14 is only rated 0.71 mm H2O I suggest something like their new Venturi HP-14 PWM that has 1.94 mm H2O rating. Other fans like be quiet! Silent Wings 3, Thermalright TY-147A Sq and Phanteks PH-F140MP all have much better abiliy to overcome resistance and supply a good flow of air through filters and fancy vent grills. SP140 is way down my list.

As for spacing the fans into case away from front vents .. all you will do is improve case airblow, and lower case airflow. The front intakes have to bring cool air into case, not re-circulate air already in the case. In case you are intersted, here is a basic guide to case airflow and how to optimize it.

How Airflow Works

Airflow is simply displacement; for air to come into case, air must be leaving case .. or .. for air to leave the case, air must be coming into case.
Think of the air around us as water and we are divers in it and a sunken van is a computer case.
  • We can't move more water into the van (case) through an open window (vent) unless we have another open window (vent) somewhere else in the van (case) moving the same amount of water (air) out through a window on other side of van (case).
  • We can't take any water out of van unless we have the same amount of water coming in at the same time.
  • This means we have to have as many open windows flowing water into van as we have open windows flowing water out.
  • This is exactly how airflow works. Intake fan pushing / flowing air into case is pushing / flowing the same amount of air out of case.
  • Adding an exhaust fan can help case airflow, same as adding a back fan on some coolers.
  • But with good case intake fans we don't need exhaust fans, same as good cooler / radiator fans don't need pull fans. ;)
  • This is why I used to always change stock intake fans. Now some cases are finally coming with intake fans that have high enough pressure ratings to not need 'helper' (exhaust) fans. :thumb:


Setting up a case for optimum cooling

Setting up the case for optimum cooling is often the hardest and most time consuming part of a build... And the most neglected by most builders.

  • There is much more to cooling than good cases and good CPU / GPU coolers. Add the fact that many GPU's make more heat than CPU means getting that heat out of the case and keeping a cool airflow to components can be a challenge.
  • Cases, especially those with filters, usually benefit from fans with higher static pressure ratings than stock fans... "cooler" fans instead of "case" fans.
    Intakes typically have more restricted than exhaust because of air filters, more restrictive grills, HDD cages, etc.
  • I prefer more intake than exhaust. And don't confuse number of fans with amount of airflow... or airflow with airblow
  • airflow is flowing cool air from intake to component and flowing hot air from component out of case without the hot air mixing with the cool air.
  • airblow is lots of fans blowing air with some of hot air from components mixing with cool air making it warmer resulting in warm air not cooling components as well as the cool air will.
  • Putting fans in case as intake and/or exhaust is only the first step. These fans only move air in and out of case.
  • This does not mean heated air is not mixing with cool air.
  • Nor does it mean cool air is going to where it is needed.
  • Getting the air to flow inside of case properly is even more important. We still need to manage where the air flows inside the case. We can do this several ways; deflectors, more intake fans.. & exhaust fans, removing vent grills, removing HDD cage, using fans with higher pressure/airflow, building ducts to or from CPU/GPU cooler, etc.
  • Using a remote temperature sensor to monitor what air temps are is the key to finding out where the cool air is flowing and knowing heated air is not mixing into it. By monitoring this we can than make changes to get airflow the way we want it.
  • Keep in mind your case needs to flow more air than components do. It isn't so much how many fans but how well they flow air through the case. If component fans move more air than case fans move through case components are using their own heated exhaust to make up the difference and case heats up. Good rule of thumb is 25-50% more case cfm than component cfm but well tuned airflow can be almost equal equal.
  • Traditional tower cooler exhausting toward back of case must have rear / rear & top back case exhaust fan that remove as much or more cfm than cooler fans exhaust.
  • A duct from back of cooler to back of case (like Thermalright HR-22 uses) is also an option that works very well.

Example of Cool & Quiet System
  • My Define R2 system has three TY-140 74cfm intake fans. (no exhaust fans) in case while CPU has TY-143 130cfm fan and GPU has two TY-100 44cfm fans
  • Case = 222cfm
  • Components = 218cfm
  • Air temp inside of case going into coolers is never more than 3c above room.
  • 2 front TY-140 & CPU cooler TY-143 fans are PWM controlled by CPU
  • Bottom TY-140 & GPU TY-100 fans are PWM controlled by GPU


It is amazing how much cooler a system runs (and quieter) once the case airflow is setup to keep heated exhaust from contaminating cool intake air. Once we start doing these things, the concept seems like a no-brainer, yet most users seem to think more fans and/or powerful fans are needed to get better cooling. The reality is it's not so much the power and amount of air the fans move. but the currents / pathways the air flows in on it's way through the case that is important. Fan power/airflow only needs to be a little more than the amount the components are using at any given time. Using too many, fan and having too much airflow airblow can be as detrimental to case's flow pattern as not using fans with enough flow .. and if the flow isn't tuned to keep cool and heated air separate the system is not going run as cool as it can.


How to monitor air temperature different places inside of case:

  • A cheap indoor/outdoor thermometer with a piece of insulated wire and a plastic clothspin works great.
  • Made up with floral wire and tape. We don't want anything to short out with metal. ;)
    1832154.jpg

  • Clip and position sensor where I want to check the temp. Make it easy to see what the air temp going into components actually is relative to room temp. ;)
  • Optimum cooling is when air temps going into coolers only being 2-3c warmer than room.. 5c or less is good.
Click to expand...
 
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doyll said:
Get better fans. I suspect those are the stock fans and the Dynamic GP-14 is only rated 0.71 mm H2O I suggest something like their new Venturi HP-14 PWM that has 1.94 mm H2O rating. Other fans like be quiet! Silent Wings 3, Thermalright TY-147A Sq and Phanteks PH-F140MP all have much better abiliy to overcome resistance and supply a good flow of air through filters and fancy vent grills. SP140 is way down my list.

As for spacing the fans into case away from front vents .. all you will do is improve case airblow, and lower case airflow. The front intakes have to bring cool air into case, not re-circulate air already in the case. In case you are intersted, here is a basic guide to case airflow and how to optimize it.
Click to expand...

This is excellent, thank you.

Also OP, couple of JayzTwoCents videos that might help you pick the right fan/fan setup.


 
Read the rest of the thread.

I solved the problem by making my own dust filter out of dryer sheets. The fans move a lot of air but are extremely low pressure. The stock filter is like 1/3 solid plastic and doesn't provide enough airflow. Oddly, the PSU + bottom fan filter is much better, but it doesn't have magnets, so it can't be attached to the front panel.

Weird design choice by Fractal.
 
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TaintedSquirrel said:
Read the rest of the thread.

I solved the problem by making my own dust filter out of dryer sheets. The fans move a lot of air but are extremely low pressure. The stock filter is like 1/3 solid plastic and doesn't provide enough airflow. Oddly, the PSU + bottom fan filter is much better, but it doesn't have magnets, so it can't be attached to the front panel.

Weird design choice by Fractal.
Click to expand...

Unless you're putting a radiator on the front, I wouldn't worry about low pressure. If you are, then high pressure fans are what you need.
 
TaintedSquirrel said:
Read the rest of the thread.

I solved the problem by making my own dust filter out of dryer sheets. The fans move a lot of air but are extremely low pressure. The stock filter is like 1/3 solid plastic and doesn't provide enough airflow. Oddly, the PSU + bottom fan filter is much better, but it doesn't have magnets, so it can't be attached to the front panel.

Weird design choice by Fractal.
Click to expand...
The problem was not the filter framing strips. With no mesh it is probably >90% open area. The front cover venting has only a small fraction as much vent airflow area as the stock filter frame and filter. As I said before the problem is the fans Fractal Design supplies with the case. Even running at full speed they can only just barely overcome the resistance of case venting and filter.
 
Just ordered 3x NF-A14 FLX to replace these. Not sure how much of an improvement there will be but I figure it's a good investment.
Was hoping to get Noctua's new fans, though.
 
TaintedSquirrel said:
idk if you're serious but using strings, ribbons, and ropes to measure airflow is pretty common in aerodynamics.
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Not really use to measure airflow, but to check direction of flow. What was fan speed in those tests?
Airflow will change dramatically with components in and sides side.
 
I know you went away from the idea to use long screws to distance the fans into the case. But I would still like to point out that that would be a bad idea. Because if the front filter is as restrictive as you claim, adding spacers would just give room for the fans to suck air from around them instead. Meaning you're just recycling the air inside your case instead of pulling fresh air through the front filter. And it's better to have a lower flow of fresh air through a filter than just blowing the existing air inside your case around one more time.

Yes I am exaggerating, of course some fresh air will still be pulled into the case. The point is that spacers would be a bad idea to solve this problem.
 
TaintedSquirrel said:
After a week of waiting, Amazon recalled my order because of the hurricane *yawn*.
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Yeah, lots of damage that will take month to rebuild. Lots of people suffering from Harvey and Irma .. and now Jose might be coming. Trap some of it's winds when it goes though and use that to cool your system for the next few years. :D
 
SvenBent said:
man i feel for you. Nobody is probably more hit bad stuff than you not getting your fan due to the hurricane...
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doyll said:
Yeah, lots of damage that will take month to rebuild. Lots of people suffering from Harvey and Irma .. and now Jose might be coming. Trap some of it's winds when it goes though and use that to cool your system for the next few years. :D
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The eye went over my house. Was hoping to pass the time working on the PC until power comes back.

We also had some bottled water in the order, which thankfully did get here in a separate box.
 
Always use high static pressure fans for intakes. ALWAYS. High CFM does not necessarily mean it is high static pressure.

With exhaust fans you can use high CFM fans because you have nothing in front or behind the fan obstructing airflow. On intakes, there's a fan grill up front and computer hardware (e.g. heatsink, cables, drives, video card, computer frame, fan filters) near the fan. You need high static pressure fans to continually push/pull the air flow through obstructions instead of one that spins through it at the highest speeds.

Think of it like trying to haul a trailer with a sports car instead of a truck. With a clear road, a sports car (low pressure fan) can go fast. Put a load on it (fan filter) and suddenly it's slower than a truck meant to haul the load.
 
OP, don't listen to the haters in this thread. They think that the yarn was suppose to be horizontal to equal good airflow.

Filters do block airflow, I don't think new fans will make a big difference unless the new fans spin over 2000RPM. Those fans in the fractal case are decent fans. I would get faster spinning fans or leave the filter off for best airflow.
 
Yeah I've tested the included Fractal fans in builds for friends/family. They're what you'd expect for included fans - not great.
There are certain fans that actually scale very well at low RPMs - the Silent Wings 3 specifically (as doyll already mentioned), if silence is your priority.

62lGSlwl.jpg


These are fairly new fans compared to my Phanteks, and being noise-focused, that's what they excel at. You can also compare it directly against the A14 FLX.
I wouldn't mind picking some up if they were discounted to say $15, down from the usual $20...
 
Looking good.
My PC being off for 4 days killed my mouse apparently, was a PITA posting this lmao.

Hj7G885.png
 
hmm not sure aboot that. the extra bottom intake will feed the gpu(s) more fresh air. wouldn't be that hard to test.
 
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