PWM cooling fan(s) control using ECM

[erick_e]

I just got my 17" brushless fan and I am going to try to figure out how to have my factory ECM control it. Since these brushless fans are supposed to be factory on the 2014+ Corvette, I was able to compare the 2014 tune for brushless fan against the pre 2014 fans that have a separate PWM controller as seen in this thread.

In HPTuners the 2014 fan is listed as a PWM EV fan operating at 100Hz where the pre 2014 fans are PWM electric operating at 128Hz.

I'm thinking that I can just change the fan type and frequency in my tune and it should work.

Any thoughts?

[andrewb70]

Originally Posted by erick_e

.....
In HPTuners the 2014 fan is listed as a PWM EV fan operating at 100Hz where the pre 2014 fans are PWM electric operating at 128Hz.

I'm thinking that I can just change the fan type and frequency in my tune and it should work.

Any thoughts?

...

I think that should work!

Andrew

[andrewb70]

I have a little update. I've been driving the Cougar quite a bit and working on the tune, so I decided to play with the fan settings a bit. I had the fan set to 40% in the 190 and 200 degree cells, but I wanted to see how low I could go with the fan speed at idle and still maintain temps in the 193-195 range. So I lowered fan speed to 25% in the 190 and 200 degree cells and let the car idle for 5 minutes. No change in temps. This fan just kicks ass...

I also scaled the temps above 40 mph so that the fan doesn't kick on at all until 200 degrees. I think for me, having a hole in the hood helps a lot...LOL

My ultimate goal is to cycle that fan as little as needed...

Andrew

[Che70velle]

Great info here guys!

[erick_e]

Originally Posted by andrewb70

I think that should work!

Andrew

Well, I finally got around to testing my theory about the brushless fans working with the factory ECM.

Bottom line, the factory ECU can control these fans. Since I had already replaced by previously burnt up fan connector I was able to quickly connect the brushless fan to my car with another connector. Its just as simple as connecting the B+, B-, and PWN wires together. The factory ECM commands 128Hz, and the brushless fan is recommended for 100Hz. SPAL tech support says 128 should be OK, but 100Hz would be optimal. This can easily be changed with HPTuners or EFI Live. Changing the PWM type was not required. PWM Electric is what is required, not PWM EV like the C7 Corvette.

Once connected I fired up the Tech2 and commanded the fan on. Below you see it running at 90% duty cycle. I had the fan facing down to create restricted airflow (to simulate radiator, condenser and
heat exchanger). Notice it only dropped .3v at 90%. Not bad considering the vehicle wasn't even running.



I didn't have time to test fit Dewitt's fan shroud with my EForce. Hopefully it fits, it's a beautiful shroud. But if it doesn't fit I might be able to make the brushless fan work with the original shroud with an adapter. The fan blade is the same dimension as the OEM blade, but the motor is a little smaller in diameter. I'll cross that bridge when I have to, if I have to. Hopefully the Dewitt's shroud doesn't interfere with my coolant lines and I don't have to.

[GregWeld]

Originally Posted by erick_e

Well, I finally got around to testing my theory about the brushless fans working with the factory ECM.

Bottom line, the factory ECU can control these fans. Since I had already replaced by previously burnt up fan connector I was able to quickly connect the brushless fan to my car with another connector. Its just as simple as connecting the B+, B-, and PWN wires together. The factory ECM commands 128Hz, and the brushless fan is recommended for 100Hz. SPAL tech support says 128 should be OK, but 100Hz would be optimal. This can easily be changed with HPTuners or EFI Live. Changing the PWM type was not required. PWM Electric is what is required, not PWM EV like the C7 Corvette.

Once connected I fired up the Tech2 and commanded the fan on. Below you see it running at 90% duty cycle. I had the fan facing down to create restricted airflow (to simulate radiator, condenser and
heat exchanger). Notice it only dropped .3v at 90%. Not bad considering the vehicle wasn't even running.


https://www.youtube.com/watch?v=CZ1ihcmsoo0


I didn't have time to test fit Dewitt's fan shroud with my EForce. Hopefully it fits, it's a beautiful shroud. But if it doesn't fit I might be able to make the brushless fan work with the original shroud with an adapter. The fan blade is the same dimension as the OEM blade, but the motor is a little smaller in diameter. I'll cross that bridge when I have to, if I have to. Hopefully the Dewitt's shroud doesn't interfere with my coolant lines and I don't have to.

[erick_e]

Originally Posted by GregWeld

Thanks. I wasn't sure how to insert YouTube videos. I tried the standard [YT] but it didn't work. I updated the post.

[dontlifttoshift]

Andrew, bolding mine.

Originally Posted by erick_e

Well, I finally got around to testing my theory about the brushless fans working with the factory ECM.

Bottom line, the factory ECU can control these fans. Since I had already replaced by previously burnt up fan connector I was able to quickly connect the brushless fan to my car with another connector. Its just as simple as connecting the B+, B-, and PWN wires together. The factory ECM commands 128Hz, and the brushless fan is recommended for 100Hz. SPAL tech support says 128 should be OK, but 100Hz would be optimal. This can easily be changed with HPTuners or EFI Live. Changing the PWM type was not required. PWM Electric is what is required, not PWM EV like the C7 Corvette.

Once connected I fired up the Tech2 and commanded the fan on. Below you see it running at 90% duty cycle. I had the fan facing down to create restricted airflow (to simulate radiator, condenser and
heat exchanger). Notice it only dropped .3v at 90%. Not bad considering the vehicle wasn't even running.



I didn't have time to test fit Dewitt's fan shroud with my EForce. Hopefully it fits, it's a beautiful shroud. But if it doesn't fit I might be able to make the brushless fan work with the original shroud with an adapter. The fan blade is the same dimension as the OEM blade, but the motor is a little smaller in diameter. I'll cross that bridge when I have to, if I have to. Hopefully the Dewitt's shroud doesn't interfere with my coolant lines and I don't have to.

[andrewb70]

Thanks Donny!

I follow this thread closely, but somehow I missed that video!

Looks like those new Spal fans with the controller built in would be easy with the Dominator! I am always looking for cool, new stuff for future builds!

Andrew

[stan65]

Anyone know what PWM voltage the ECM is outputting? 5v, 12v?

Thinking I may tackle it as an arduino project as I have GMPP LT4 controller.

Stan