Posts Tagged ‘Testing’

Welcome to my round 11 fan testing.  This is a fairly small round of fans from the kits I previously tested.  Rather than do my normal written form, I’m trying to do this more video based.

Before I do that, I would first like to thank my parts sponsors, without their support this test wouldn’t have happened:



Kit Fans Intro

This video does some physical comparisons of the fans and gives you a good close up look of the fan, sleeving, build quality, etc compared with my previous best performing fan the Gentle Typhoon.

Fan Test Rig Description

This video is just a quick overview of the flow bench and meters used in the fan testing to follow.

Individual Fan Tests

The following videos are of the actual test run on each fan recorded with audio and stepping through 50FPM air flow results.  You can now easily adjust two or more fan videos to like air flow numbers and pause them both, then switch back and fort for a direct apples to apples air flow comparison.

Larkooler Kit Fan

Corsair H100i SP120 Kit Fan

Swiftech H220 Kit Fan

XSPC 750 Kit Fan

Servo Nidec Gentle Typhoon AP-15

Extracted Results

These were pulled from the video, by isolating a looped region where air flow was close to the 50FPM increment.  This provides the resulting detail read on the meters and a calculated RPM.  On the right are some subjective noise quality comments I added as I reviewed and extracted the results.


Summary Radiator Noise Level vs Radiator Air Flow

This is the “Meat & Potatoes” result.  While I wish I could measure noise quality in a good quantitative way, that’s really not possible.  The next best thing is to compare noise levels when mounted to a radiator at like air flows through that radiator.  It takes into account the fans pressure capabilities and puts it in a more real world condition.  It’s not perfect, but the best thing I’ve been able to come up with to simplify radiator noise performance.  Fans that extend further right are capable of higher air flow maximum results at 12V.  Fans with lines lower on the Y axis are producing more air flow per noise level.


No real surprise, but the kit fans all tested relatively the same (most within 3dbA or less differences which fall within the “barely perceptible” level).  The Helix fan did for some reason have a bit higher than expected harmonics on the radiator bench which didn’t seem to be as noticeable when actually testing in a case, but it is something I heard a little when trying push only.  In push+pull I noticed most of that helix harmonic disappeared.

I would consider the kit results to be relatively similar, they are like most fans and all perform roughly the same.  The Gentle Typhoon however does seem to retain that unique ability on a radiator and tested upwards to 8-9dBA lower in noise level at 12V than other fans producing the same flow.  The H100i fans and their 2700RPM capability did produce the highest maximum air flow, but it comes at the prices of having a fairly gritty noise quality.  Noise quality isn’t captured well in the graph and really only something you can listen for in the videos.

The other aspect I’m now noticing that is missing from this single fan test bench is harmonics between the two same fans.  In the thermal testing using the kits and earlier noise testing, I had significant RPM harmonics issues with the H100i fans, but a single fans test scenario completely misses that.  This is something I seriously want to consider in fan flow bench future upgrades.  I think it is important to capture the “paired fan” harmonics effects as it can be fairly significant.  The helix H220 fans did really well paired together in the kit testing, but you just can’t see that in a single fan test.

Also as noted some of the pressure harmonics issues can also be mitigated for by going push + pull.  The helix fans don’t show real well in this single push test, but I found when testing four fans in push/pull on a radiator the fans worked very well together.  They are not up to Gentle Typhoon silence or build quality standards, but in use I would say they fair better than what the above chart or single fan test result demonstrates.

I also think the Larkooler fan subjectively sounds quieter than the produced dBA.  I’m not sure how to describe it, but the sound type is more lower in frequency and seem to contain less motor noise and gritty noise that is more prevalent in the other fans.  It has a noise quality that reminds me of the noise blocker series which I’ve always liked.  Noise level doesn’t measure anything special, but I think this fan does have pretty good noise quality particularly at slower speeds.  This is another one where my own ear and the meters don’t really agree all that well..:)

This at least gives you one more perspective on the sound.  I would suggest listening to the fans at like air flow levels and make a decision not based on noise level, but what you perceive as being less irritating.  That is likely a combination of frequency, noise quality, and noise level.  Don’t put too much weight on the noise level, it is important, but it’s not the entire picture and each person and each setup will be slightly different.

So there is another round and the Gentle Typhoon retains it’s low noise/rad air flow ratio crown.  Nothing comes close…

I was in need of picking up another gallon of distilled water at Wal-mart today, and decided to stop by a few more stores and do a quick evaluation of water purity of a few different brands.  In addition, I wanted to better understand the importance of water quality and scale since there is no data on how water quality changes when run in a loop.  I’ve read or heard a few people say that store bought distilled water just isn’t good or reliable enough and that you really need to buy ultra pure water.  I have used regular distilled water in non-plated water cooling loops for years now and have even run tapwater in a loop for over a year now just for this nagging myth being spread about.  Since I bought my own water purity meter, I now had the tools needed to see for myself and wanted to share my findings.

This test is sponsored by…:)

Water Quality Meters

First, let’s look at the meters.  It doesn’t break the bank to buy these, I spent under $100 to buy them both:

I initially started testing both electrical conductivity as well as PH, but after a while realized that the PH was generally the same.  It’s hard to measure with such little conductivity, but all the samples were within 6.5-7.5 PH which is neutral.

The conductivity meter is an HM Digital COM-100


EC Range: 0 – 9990 µS; 0 – 9.99 mS
TDS Range: 0 – 8560 ppm (mg/L); 0 – 8.56 ppt
Temperature Range: 0-80 °C; 32-176 °F
Resolution: 0-99: 0.1 µS/ppm/mS/ppt; 100-999: 1 µS/ppm; 1000-9990: 10 µS/ppm. Temp. resolution is 0.1 °C/F
Accuracy: +/- 2%
EC to TDS Conversion Factor: Non-linear conversions for KCl, 442TM or NaCl solutions, selected by the user.
Calibration: Digital calibration by push button.
Probe: Detachable platinum electrodes
Housing: IP-67 Waterproof (submersible; floats)
Power source: 3 x 1.5V button cell batteries (included)  (model 357A)
Dimensions: 18.5 x 3.4 x 3.4 cm (7.3 x 1.3 x 1.3 inches)
Weight: 90.7g (3.2 oz)

The COM-100 meter is calibrated with a 1413 µS solution.

The meter comes factory calibrated with a 1413 uS solution and appeared to be reading fairly accurately, so I proceeded to test with that factory calibration.

Electrical conductivity or EC is a commonly used indicator to measure water purity.  While conductivity itself isn’t the only measurement goal, total dissolved solids (TDS) in ppm (Parts per million) are also routinely converted from this number.  To keep it simple, I’m just measuring the conductivity in this test and including a conversion table that was included with the meter to TDS if you are so inclined.  Distilled waters typically should be better than 10uS where municipal water systems could be as high as 500-800uS.  In water cooling we have had all sorts of numbers thrown out there with suggestions that grocery store distilled wasn’t good enough.  In addition there was not any data in regards to how quickly this water becomes ionized in the loop which is important when considering the relevance of purity.

So with that….let’s get on with some measurements..:)

Every now and then the discussion comes up in forums where someone gets the idea that they want to run their radiators passively without out any fan power at all.  The discussion recently came up again and I decided to dig out some old test data and share a quick blog on what I found back on my V1 test bench while testing a low density double thickness 480 sized radiator.

When I was testing my TFC480 radiator back on my V1 test bench, I tried exactly that.  I even dialed down the heat to a bare minimum 100 watts to test a very small (perfect conditions) scenario.  The TFC 480 radiator is a premium double thickness low density radiator that performs really well with low speed fans, so I figured it would be the pefect test case.

So I proceeded to use my very smallest heater, and in the optimal open bench setting with the radiator pointing upward proceeded to test at 100W heat load.

1 hour went by….still not stable

2 hours went by…temps still climbing…

Almost 3 hours later, temps are still climbing…The tubing was hot to the touch and I began to worry about my heaters fracturing in their glass tubes and decided to call it quits.   This is what that test data log looked like:


I consider an “Average” radiator setup performance to be around a 10C water/air delta and the radiator nearly doubled that on this incomplete test.  Perhaps you could get passive to work in a case where you had a power supply pulling air through the case and radiator, but then that’s not really passive is it?

Bottom line, passive operation on conventional radiators just doesn’t work well enough to consider it a useful option.  I would ask why bother when 600RPM fans are quieter than a mouse fart anyhow…:)

It would take a very different type of radiator and much much larger surface areas for passive to work well.


While generally most testing is only good relative to the same test bench, it’s also nice if you can get some level of absolute accuracy for a sense of scale and to speak more of a common unit of measure. I do this testing all for hobby, so none of my meters are sent in for any sort of monthly calibration or certification.  While I thoroughly enjoy my little testing tools, they are not proven accurate and I simply don’t have a means or desire to do so while hobby testing. It’s very expensive and cost prohibitive at the recreational level I’m working within.

I figured the next best thing is to run my own checks using basic tools I have readily available.  Those basic tools include a  graduated container, a stop watch, and section of tubing to be used as a static pressure head water filled tube manometer.  In spirit of sharing information, I wanted to include this in a mini “how to testing” blog of sorts.

Some of these methods can also be used for casual testing.  If you think you might have a flow problem, but don’t have a meter…you can test your flow rate fairly accurately by the method described below.  Also if you think your pump is not up to par, you can (with a fair amount of work) also test pumps using tube manometers and bucket/stopwatch for flow rate.  I’ve done this before…long ago, but it’s very much a plausible method to extract a more scientific level of data or to test the accuracy of meters.

Testing Flow Meter Accuracy

Testing flow rate (Gallons Per Minute) is fairly simple.  Find a nice large known volume to fill and measure the time required to fill this known volume.  In my case I had an old 5 gallon race gas can that had gallon increments.  Mixing 2 stroke gas requires some level of ratio precision, so these cans are a bit more graduated than a normal gas can.  If such a graduated volume isn’t available, you could also create your own by using a smaller known volume and marking the container as you fill it up with the smaller known volume container. (A large bucket and an old empty one gallon milk jug would be one cheap and readily available option).

Moving onto the next variable…Time in Minutes. I took my DROID phone (Not the first time I’ve used it for science!), downloaded a stopwatch app, and proceeded to test in gallon increments.  I measured the time in minutes and seconds to fill the container from zero to the 5 gallon mark.  Here is the test setup and results:

Per the King Instruments Site, the larger King Instruments 7520 should read within 2% of full scale or .02X5 = 0.10 GPM.    I got around 1.7% of the measured scale or .06GPM maximum.  Flow rate calibration appears to be within specification…very good!

Testing Pressure Meter (Manometer) Accuracy

Testing lower levels of pressure is also fairly simple.  A manometer is nothing more than a pressure meter that measures the pressure  difference between two points.  If you disconnect the negative pressure terminal, it is now exposed to atmospheric pressure.  When you zero out to the atmosphere, you now have gauge pressure.  If you fill a column of water on the positive terminal, the net column height (Max level minus level in terminal tube) is the actual gauge pressure differential measured.   The tricky part is finding something plumb that you can measure a column of water.  Note that the tubing doesn’t need to be straight, but your measurement from water level at the top to lower water level needs to be plumb vertical.  Excuse the spider webs…:)  I just connected a funnel and clamped it to a column in our vaulted ceiling area.

Per the Dwyer Site, the Series 477-5 is capable of reading .5% of full-scale.  Full scale is 30.00PSI or 831 inches h2O.  So the possible error is .5% of 831 or 4.1 inches of water.  I measured an error of 1.2% of 100 inches or about 1.2 inches which is well within the 4.1 inch specification.  Looks like my manometer is also reading just fine within specs..:)

Manometer Pressure T fittings

In manometer testing, I think there is also some importance in the T line fitting used.  If it’s not a large smooth pass through fitting or the fittings are not perfectly identical, there could be some induced pressure differential from T fittings.  Like the venturi in a carburetor, if you reduce the sectional area, you will create a vacuum.  There is also the possibility with a large opening for the pressure junction that you could get odd flow momentum effects such similar to a pitot tube. I have seen some odd things in the past that makes me a bit careful about these fittings.  I think it’s good practice to spend some time on these fittings to minimize disturbance of flow and ensure equal pressure measurement conditions.  Water flow does change states and behavior as it increases in velocity, so keeping it down to nice slow speeds may help minimize measurement oddities.

I created my own T fittings from 1/2″ copper tubing and brass fittings soldered.  This leaves a clean and thin walled 1/2″ ID fitting with minimal turbulence and restriction.  They also have very small port openings leading to the manometer in an effort to minimize both restriction and any pitot tube like effects. I have used these custom manometer fittings for some time now and have been pleased with repeatability of pressure drop or pump tests.


While absolute accuracy is not really important at all in comparison related tests, it’s nice to know that my meters are within at least manufacturer specification.  That’s one way to do some checking on your flow and pressure meters if you’re interested and I’m pretty happy now that I finally checked mine.  There is also not much information on this, but I think it’s worth your time building your own T fittings when doing manometer related measurements.  These test methods can also be used by other reviewers that don’t have a manometer or flow meter.  I think it’s always good to do some of the more down to earth type tests like this now and then.  A number displayed on a magic box is worthless without the understanding of what it’s actually doing.  While time consuming, these forms of pressure and flow rate testing are also very educational.  I think they should be mandatory before anyone starts testing with a flow meter or digital manometer….:)

Looks OK from what I can tell..time for more pump testing..


Same as my round 6 testing and methods with the exception of using a Hardware Labs 140mm SR1 radiator. Seems as though we’re getting more and more 140mm radiator options, so it would be nice to get a feel on how a fan performs on one from a noise perspective. This thread is devoted toward more real world like testing of fans physically mounted to the HWlabs SR1 radiator.

Special thanks to the many generous sponsors:

Here is the list of fans, sponsors and results currently complete. I plan to do these 140mm fans as well as a few of the top performing 120mm fans on an adapter for 120mm options.


The 120mm fans are tested on a BGears slim profile 120>140 adapter. Soo…the 120’s will be getting a small shroud benefit from being further from the radiator fins. In order to see how much if any this diffence means, I’m going to retest my top 140 fans with a shroud and include them in the below chart.
The below chart is sort of a mix, not all tested equally, so take that into account when reviewing:

140mm fans only: It’s pretty tight with most of the results within the 3dbA or lower “Barely Perceptible” limit. There are however some fairly notable sound quality issues, particularly with the 7 blade fans at higher speeds including the yates. For low speed, I would tend to favor the Thermalright X-Silent, for high speeds, the Aerocool Shark.

120mm fans on an adapter: This is a bit apples to oranges with the adapter, but it’s fairly surprising just how close 120mm fans perform to 140mm fans on a CFM per dbA ratio perspective. The 140mm fans do have some CFM per RPM advantage and seem to produce a slightly lower frequency tone, but their noise levels were pretty much the same. This makes some of the stronger performing 120mm fans a very viable option on 140mm radiators. I had really hoped the 140mm fans would be a huge benefit over 120s, but I’m just not finding that. There is a good sized advantage to the larger 140mm radiator and reduced restriction, but the gain is in the radiator frontal area, not the 140mm fan itself.

I have a few more 140’s coming but that’s what I think so far…