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DIY fan test chamber

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DIY fan test chamber

Starting this to help anyone looking to test the CFM performance of their fan project. I was not able to find anything credible on the web while researching various fan CFM ratings so I decided to figure out how to get it done myself.

The link to the thread on that got me here...
http://www.cumminsforum.com/forum/3...ic-fans-research-discussion.html#post18938121

I am using this anemometer to measure the CFM of the fans, it has an averaging function that will take 20 samples and average them. It will also give min/max values along with the average.

AN100 - CFM/CMM Mini Thermo-Anemometer

and using this DC Clamp meter. Unfortunately it does not have a peak hold function so I cannot provide that info.
MA435T - 400A True RMS AC/DC Clamp Meter + NCV

Started out with 1 4x8' sheet of plywood. Did the math against my radiator core and found I was able to cut the test box out of 1 sheet. I did find some errors I made in calculating the cuts. I forgot to include the thickness of the wood for some of the cuts so I ended up having to imrovise as I built it.

My design is intended to allow to connect to the factory radiator which has a 27x30.5" core. The idea is to be able to swap in a plate with the fan mounted to an interface box and measure its performance through a 12x12x21" duct. After building this fixture and firing up the fan it occured to me that this setup is not a true free air flow setup since it is drawing through the 12x12" port so the measurements I'll get out of it will be partially loaded. I think to get this right I'd need a duct with the area of the fan connected to the interface box. I may change the 12x12" measurement box to match the fan dimensions. Not 100% sure yet.

On paper draw up your fan test box and see how the cuts would need to be made so you can use 1 4x8' of plywood. Dont forget to include the wood thickness.

Once I had mine cut & I was ready to assemble I started on the smaller box. I used small brackets with counter sunk screws that would allow me to keep the interior of the measurement box free of obstructions. When tightening up the brackets you can sink the screw heads on the inside of the measurement box pretty easy.





completed measurement box






Next build your interface box



Test fit onto radiator core




Add measurement box panel and cut out opening for measurement box. In my case it was exactly a 12x12" opening.









Mouth the measurement chamber to the interface chamber



Next on the fan mounting plate, cut an opening equal to the fan blade. I beleive the if a fan is attached to an existing shroud it can be mounted to this plate. All openings that are not sealed against the fan mounting plate will need to be sealed.


Next mount the fan to the fan mounting plate




Next mount the fan mounting plate to the interface box and you should be ready to go. In this pic I have everything stacked on top of the interface box. Fan is mounted below, battery, relay conections are also below.


While this is not finished, still need to seal the measurement box and attach to interface box, it's should be clear as to what needs to be done to finish it off.

To take measurements you will need to mark 8 spots on the measurement box, 2 on each side and collect the CFM data from each position. oNce all of the measrements are taken, average the 8 readings, the average of all 8 readings should be a good indicator of the fans capabilities measured in CFM. If you are using a 12x12" measurement box then you need to keep in mind that there is a load on the fan and it is not a free air test.

If you want to have 100% free air test then the measurement box needs to be larger than the area of the fan (I think) and the dimensions need to be plugged into a CFM calculator. I recommend calculating the area of the fan blade and go just over it.

DO NOT FORGET TO FACTOR IN THE SENSOR HEAD AREA IN YOUR CALCULATIONS FOR MEASUREMENT BOX AREA.

Circle Area Calculator

Rectangle Area Calculator

ENGINEERING.com | Air Flow Conversion Calculator

My fan... a '97 volvo 850 fan seems to pull really hard and it will be interesting to see how it does.

If anyone repeats this work with another fan and collects some data please feel free to add it here. (if the thread is closed contact a moderator and have them open it, they will be happy to do it). It would be nice to have good solid data for anyone else who is looking for it. I know it was all hearsay on what the taurus fans & volvo fans pull

If I blew it somewhere and need to be set straight, feel free to let me know. :thumbsup:

EDIT: Adding
I marked the measurement box with 3 positions on each side for 12 data points total. There is a small lip on the probe that allows me to place the probe within the marks and give me repeatable locations for measurements.
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Discussion Starter · #2 ·
Volvo 850 MY 1997
High Speed data
3349 CFM @ 12.3V/27.3A
Measurement box = 12x12", Volume = corrected 138.0 square inches (correction for measurement probe).

Low speed data
2695 CFM @ 12.8V/13.8A

post with data from each position measured
http://www.cumminsforum.com/forum/g...706266-diy-fan-test-chamber.html#post19532138


High Speed data, battery jumpered to the truck
3611 CFM @ 13.6V/28.4A


Taurus Data (battery + charger)
High Speed data
3438 CFM @ 12.5V/27.5A
http://www.cumminsforum.com/forum/g...706266-diy-fan-test-chamber.html#post19559146

Old Style Volvo Fan, 1996 & older, S-Blade type
High Speed data
3099 CFM @ 12.2V/25.8A
http://www.cumminsforum.com/forum/g...706266-diy-fan-test-chamber.html#post19677578

These 2 tests are no good... fans fight against each other. turned on 1 fan and the other fan spins. Pulled the test duct and the other fan stops.
tried to measure around perimeter and there is a lot of turbulence.
Dual volvo fan test
Hi speed test, 50A charger hooked up, same 12x12" test duct.
4536 CFM @ 12.1V/48.9A

Dual volvo fan test
Lo speed test
3637 CFM @ 12.3V/26.2A
 

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Discussion Starter · #5 ·
Data collected... Here is what I got. Keep in mind this is WITH a pressure drop as the measurement box is not sized for a free air test. I discovered this after making the box.

Volvo 850 fan MY 1997
Battery Voltage = 12.3V (battery on a charger)
Current on HI = 27.3A
Average CFM = 3349 CFM

Measured 12 data points around the perimeter of the measurement box
1 3685
2 3205
3 3448
4 3186
5 3352
6 3230
7 3365
8 3198
9 3467
10 3313
11 3415
12 3320


Low speed data
Volvo 850 fan MY 1997
Battery Voltage = 12.8V (battery on a charger)
Current on HI = 13.8A
Average CFM = 2695 CFM



1 2802
2 2699
3 2757
4 2520
5 2706
6 2680
7 2751
8 2635
9 2635
10 2866
11 2648
12 2642
Avg 2695
 

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this would be interesting for fan people use for mechanical fan substituting I do hear spal makes the best and some Ford cars had some hefty 2 speed ones.
 

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Discussion Starter · #7 ·
this would be interesting for fan people use for mechanical fan substituting I do hear spal makes the best and some Ford cars had some hefty 2 speed ones.
Yup, the whole point of doing this was to find out first hand how the fan performs compared to here-say data I have dug up on the web. ONLY 1 guy that I found actually was testing fans and providing data, he indicated how he was collecting the data and averaging them but nothing on what his setup was. That test was for a fan going into a kit he was selling.

The for fan you mention (taurus fan) is getting tested next (maybe today). There are a few DIY e-fan conversions here, one using this fan and another using the taurus fans. Both are dual fan setups designed similar to what Flex-a-lite has on the market with the taurus fans setup regularly maxing the weight out over 20k (Flex has a 18k limit).

This fan will be going in a dual fan setup attached to a ram radiator that I have in the garage and getting tested with the same box setup. Once that is done, I will know how it compares to the flex kit and will have an idea on performance before the install.

Spal does publish their fan data and is the only one I found that load tests them (indicated in the data)
 

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Discussion Starter · #8 ·
MY '97 Volvo 850 fan, battery jumpered from truck
28.4 A 13.6v (truck)

1 3781
2 3525
3 3627
4 3352
5 3601
6 3659
7 3582
8 3678
9 3672
10 3608
11 3576
12 3672

average 3611
 

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Discussion Starter · #9 ·
Taurus Fan Data

Taurus Fan data

Hi speed test
27.5A @ 12.5V

1 3537
2 3467
3 3461
4 3384
5 3429
6 3262
7 3582
8 3269
9 3352
10 3550
11 3633
12 3333
average 3438
 

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Discussion Starter · #10 ·
old style volvo fan 1996 & older, s-blade type. Looks like Taurus fan but smaller

old style volvo fan
Hi speed test
current Voltage
25.8A 12.2V

1 3218
2 3070
3 3102
4 2994
5 3026
6 3218
7 3186
8 3013
9 3006
10 3154
11 3109
12 3096
Average 3099
 

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Discussion Starter · #12 ·
So the old fan moves about 93% as much air as the newer fan. Good to know. Thanks again Steve.

hold that thought... forgot to turn the batt charger on. Do-over in progress...
 

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Discussion Starter · #13 ·
OK, updated both posts... not much change between 12 & 12.2V.

If replacing a dead fan, get the newer one, otherwise I would leave it. Your still at 6200 CFM WITHOUT ALT CHARGING! (guessing based on 2 fans) which is better than the Flex kit.
 

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Discussion Starter · #15 ·
Dual volvo fan data, box not sealed where fans meet interface chamber

Dual volvo fan test
Hi speed test, 50A charger hooked up, same 12x12" test duct.
[email protected]

1 4747
2 4593
3 4708
4 4369
5 4376
6 4382
7 4612
8 4497
9 4497
10 4407
11 4644
12 4606
Average 4536
 

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Have you looked at the Lincoln MKVIII fans? They push some serious air and are available in two speed, supposed to move more air than Taurus fans.

I run one on my street/strip car and it moves alot of air.
 

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Discussion Starter · #18 ·
Yes way back when I was pulling the taurus fans... I determined back then that they were too big to make work with what I was shooting for. One of the newer goals is to be able to swap it on the side of the road easily without modification. I have discovered the volvo fans actually fit that goal perfectly... 15mm wrench on the fan nut and 1/4 turn of the fan blade and off it comes. Then just 3 bolts holding the fan to the mount and out comes the motor. Less than 5 minutes for a tear down. 4 bolts to hold it to the shroud...

I also found that the newer fan bladed volvo fans pull nearly as much as the taurus fans do. Just 100 cfm less. Spooled05 has been running the taurus fans with zero problems towing very heavy (I forget how much he pulls but he exceeded the 18k limit the flex kit has by a bunch). I also believe with the right controller temps can be managed better, working on the arduino code already and need some hardware to hook it up to a smaller fan I have for testing.
 

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Discussion Starter · #20 ·
this thread explains it all...

http://www.cumminsforum.com/forum/3...ic-fans-research-discussion.html#post18938121

Volvo controller for relay's and the arduino (plus hardware) for temp monitoring and fan enabling. $50 bux for a fan & controller from Pick & Pull (used) not hard to find at all either.

The goal is to get temps up to 200*f and keep them there, +/- 5*f, not sure if I'll be able to do this because there is not much heat coming out of the motor for daily driving. When I had the 180*f stat in there I'd see 185~188 once in a while but that was with the stock fan in place. That fan has a mechanical side to it and will engage the clutch part way so it is always pulling air across the core.

Once this is in place it will free up the IATs so I can drive them higher up to the 120's for fuel economy. I may put a 10" fan on the CAC (I have room w/o the AT cooler in there) and control temps independent of the CTs (to a point, main fans will still cool the CAC).

ONe of the goals with the Arduino (micro-controller) is to monitor CTs, IATs and a Tow mode input pin. The idea is to flip the switch for tow mode and now IATs and CTs are controlled at a different temp, lower for more power over mpg. CTs will come off the OEM CT sensor, not sure yet on the IATs...
 
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