Radiator Fan Test Data

[Bitsyncmaster]

Would you like to test our set up? We have dual 650 cfm fans mounted to a custom tig welded shroud.

I would be willing to run the same testing I did on the OEM and Toby fans if you would like the data.

Now I know we need to do a cold power test. You would not want that fan problem I have if your AC is cycling the fans.

I've been running the bad fan for about another hour. I will let it run another hour and see if there is any improvement when I test it tomorrow.

[Elvis]

Nice infos Dave.

Are you sure the new fans are still brushed fans ?


comparing your measurements tells me what I always thought.
The new fans are not as strong as the OEM ones !

The difference in airflow is only 15%.
but 1.15³= 1,5 -> to get Tobys fans up to the same airflow they would need
50% more power- instead of 8Amps at 14V they would draw 12Amps.

Compared to 16Amps of OEM - that's what I can believe is the improvement
in the last 30 years.

If I need new fans in the future - I probably would give the new ones a chance.


BTW - any infos about original replacement fans ?
My list says it's an VW type: AU-431-959-455B can somebody confirm that ?

[Bitsyncmaster]

Looks like the bad fan is just getting worse with running. Now it starts out jumping between 3 to 5 amps. When it finally settles, it draws 7.1 amps and as it heats up (about 1 hour running) that current is down to 6.1 amps. Note: this is with 12.0 volts at the fan connector.

The other fan looks rock solid. Starts right out a 7.1 amps and still has the same current after running for one hour.

I hope Toby will replace my bad fan if I find I can not fix it myself. I think I can open it up to look at the brushes and commutator. A DC motor has to have brushes unless your driving it with some electronic controller.

I wonder how common these fan motor problems are. I think my fan fail unit will lend more data about failures. A lot of people have to turn off the current compare function to not get a flashing fan fail light. My Hervey's fans never had problems.

[WelmoedJ]

I may have an alike problem, Dave.
I have the new fans from DMCEU.

As I already told you in a private mail, I had to set the comparison check to zero.
Otherwise I would have a flashing fail fail light all the time.
Anyway now with the comparison test I find the FF light flashes that the driver's side fan is not in good shape.
This flashing however fades away the longer I use the fans (with A/C).
Peculiarly enough, if the fans kick in because of high coolant temperature, it almost never happens that the FF light is flashing.

I still have to check with Ed.
That's also because the afore mentioned fan seems to produce a higher pitched sound that the other fan (because it may have a bad bearing?).
Eds fans also have more - curved - blades than those of John H. (if I counted correctly Eds have 10 of them).

This is just to provide additional info, but not relevant to your testing Toby's fans.

[Spittybug]

Looks like the bad fan is just getting worse with running. Now it starts out jumping between 3 to 5 amps. When it finally settles, it draws 7.1 amps and as it heats up (about 1 hour running) that current is down to 6.1 amps. Note: this is with 12.0 volts at the fan connector.

The other fan looks rock solid. Starts right out a 7.1 amps and still has the same current after running for one hour.

I hope Toby will replace my bad fan if I find I can not fix it myself. I think I can open it up to look at the brushes and commutator. A DC motor has to have brushes unless your driving it with some electronic controller.

I wonder how common these fan motor problems are. I think my fan fail unit will lend more data about failures. A lot of people have to turn off the current compare function to not get a flashing fan fail light. My Hervey's fans never had problems.

I have the Toby fans and your module and have experienced the same problem from day 1. I haven't bothered to set your comparison to off and haven't monitored the fan currents. I have physically eyeballed that both fans were working so I never bothered to delve into it any deeper. Good to hear (?) that I'm not alone.

[Elvis]

...

I hope Toby will replace my bad fan if I find I can not fix it myself. I think I can open it up to look at the brushes and commutator. A DC motor has to have brushes unless your driving it with some electronic controller.

simple test - if you swap + and - -> does it spin backwards ? if yes - it's a brushed fan.
in this case you can measure the resistance of the coils.

[Bitsyncmaster]

I did a lot of checking on fan blade design. The pitch is much higher in near the hub than at the edges. That is to provide a consistent air flow over the full length of the blade. I found the Toby fan blade to be very good, center was a little more than at the hub or end of the blades. There are lots of other tricks with fan design. Taper of the blade, sweeping the blades, number of blades even offset blades where some blades are closer to each other than other blades. The OEM fans have offset blades. Hervey's blades have "wiglets" on the front side. I guess that is to make the fan work like a longer blade.

But with my testing so far, not much difference in airflow. Just that more power to the motors will of course increase airflow.

I don't think the OEM fans with twice the power consumption is worth the minor airflow improvement. It made a big difference without the radiator blocking the inlet but that improvement dropped way down with the radiator. Probably would be almost no improvement had I tested with the AC condenser also blocking the inlet.

From the Fan Fail light problems, I have not seen a way to change the software to help. If it were just when the fans start, I would delay the current checking for maybe 5 seconds.

[Bitsyncmaster]

Got the fans removed but it looks like the motor is glued together. I send an email to Toby requesting a replacement so if he needs the old one back I won't open it.

I've got a crack in my new fan shroud. Don't know how that happened since there has not been any engine run (up to temp) or any force used in the installation or removal. Wonder if I tightened the mounting bolts to tight (cracked at the bottom right corner). Also wonder if those mounting bolts should be left not tight so it gives a little clearance for the heating and cooling of the shroud and radiator.

[Bitsyncmaster]

Got the replacment fan motor and ran if for 40 min. to seat the brushes. The test is to watch the current draw when first turned on and then verify the current holds while running for 15 min.

Passenger side starts at about 7.5 amps and within a second or two is holding7.1 to 7.2 amps @ 12 volts.
Drivers side starts at about 7.5 amps and within a second or two is holding 7.0 amps.

So it looks like these fan motors are working very good.

[DeloreanJoshQ]

Would you like to test our set up? We have dual 650 cfm fans mounted to a custom tig welded shroud.

What diameter are those Josh?