PWM cooling fan(s) control using ECM

[andrewb70]

I'm pretty sure you don't need the controllers with the brushless fans. They have everything built into the motor controllers, so you just need to provide power, ground, and a PWM- signal. Presumably the PWM- should be configured the same as with a C6 controller. This is somewhat speculative on my part.

Andrew

[Coursey]

Originally Posted by vannatta20

A 5th gen camaro e38 os will not support pwm. But a truck e38 os will. Also the e92 silverado controller will only support pwm at 100hertz. No discrete on the new stuff factory os.. The gmpp e92 controller will support discrete only. Its all super confusing and testing is the only way to know for sure. Lot of misinformation out there. I use an oscilloscope at work to see the signals. To get ac control the computer needs to get a serial on request from the bcm. We have a module the sends that signal along with tap shift commands for gen iv and gen v. This control the fan based on ac pressure as well. Works perfectly.

Originally Posted by andrewb70

I'm pretty sure you don't need the controllers with the brushless fans. They have everything built into the motor controllers, so you just need to provide power, ground, and a PWM- signal. Presumably the PWM- should be configured the same as with a C6 controller. This is somewhat speculative on my part.

Andrew

So will the 2015 Camaro ECM put out a PWM signal?

Be great if it can go direct to fans with no control super simple that way.

[andrewb70]

Originally Posted by Coursey

So will the 2015 Camaro ECM put out a PWM signal?

Be great if it can go direct to fans with no control super simple that way.

I do not know. I am not that familiar with the intricacies of the OEM ECUs. I'm sure someone will chime in.

Andrew

[dontlifttoshift]

Yes, control wire will go directly to the fan, no controller needed. You will have to change the frequency to 100hz for the spal fan instead of the standard 128hz that GM runs.

I may have that backwards, but there is a post in this thread regarding the frequency that the Spal brushless wants and it wasn't the same as GM.

[Coursey]

Originally Posted by dontlifttoshift

Yes, control wire will go directly to the fan, no controller needed. You will have to change the frequency to 100hz for the spal fan instead of the standard 128hz that GM runs.

I may have that backwards, but there is a post in this thread regarding the frequency that the Spal brushless wants and it wasn't the same as GM.

Thanks,

I just want to confirm that you are talking about using the 2015 Camaro e38 ecm.

[dontlifttoshift]

Can not confirm E38 and I honestly missed that part of the question.


Unrelated to that but relevant to the discussion, I got confirmation yesterday that Godspeed was successful with the PWM control on the E92 ecu with his GM crate LT4.

[andrewb70]

Originally Posted by dontlifttoshift

Yes, control wire will go directly to the fan, no controller needed. You will have to change the frequency to 100hz for the spal fan instead of the standard 128hz that GM runs.

I may have that backwards, but there is a post in this thread regarding the frequency that the Spal brushless wants and it wasn't the same as GM.

Donny,

The genIV ECUs and C6 fan controller want 128Hz. I don't recall anywhere in this thread where 100Hz was called for, but I may have missed it. It would be great to get a definitive answer on this, since I am primarily interested in making the Holley Dominator work with the new Spal fans and I can easily change the frequency.

Andrew

[durhamray1]

Originally Posted by andrewb70

I'm pretty sure you don't need the controllers with the brushless fans. They have everything built into the motor controllers, so you just need to provide power, ground, and a PWM- signal. Presumably the PWM- should be configured the same as with a C6 controller. This is somewhat speculative on my part.

Andrew

This is the information that I got from Spal on my brushless fan assy that I got from Wizzard Cooling , I think it answers all of the questions about wiring the internal PWM controller.

[dhutton]

That is awesome info. Thanks.

Don

[Tony V]

Ok guys I’m trying to circle in on how I want to drive my fans and need a little help. There’s probably 15 different ways to do it but here’s where I’m at:
• Must be PWM other than that I’m open
Currently I have:
• Holley HP ECU
• 2 C6 PWM modules
• 2 13” Spal Brushed Fans (VA13-AP70/LL-63A
Full disclosure I tracked it and drove it for 18mths with I C6 PWM driving both fans but mid way through something “gave up” and the fans wouldn’t come on. So at the track I wired in two relay’s to drive my fans (on off). Never figured out why they stopped, just assumed I couldn’t drive both fans with 1 PWM modules. After that the car went into paint and everything came off.

Ok now its 2020 (which sucks for its own reasons) I’m putting everything back together and I’m doing a little research. First thought…did I screw up and try to drive PWM with a brushed fan? The Fans worked perfectly after I wired them to relays but did I fry the PWM?
So here’s my thought process
In Option #1 in my picture was my initial thought was just add another PWM but the more I read up about it, not sure you can do that with brushed fans.
Option #2: swap out fans with brushless fans and drive them with the Holley ECU and the Spal fans use a temp sensor to adj speed.
Option #3: same as option #2 but use the PWM table in the ECU to drive speed.

Any guidance or help would be appreciated