so, I've not found anywhere on the internet that shows this actually working. e38 ecm corvette os sends a pwm to a box which then outputs DC voltage straight to the brushed fan motor to control speed. this fan being a 400watt. and just about every c6 has heat issues in 100+ deg stopped traffic days. aftermarket fans at 900$ with the vette tax. well we now have factory brushless fans, double the wattage, like 800watts, for 300$ from gm parts direct. that would cool just about anything, since brushless, they moved the pwm controller box into the brushless on the fan motor. these fans still have a pwm signal from the ecm, but for the life of me, I can't find out if it's the same as the old e38 type, I read that gm uses up to 3 different types of pwm signal. and that these new fans might be the same type as used to control the full size truck belt driven fan speed control. but I'm not even sure if that's the same or different than the vettes.
has anyone ran across any info on this? there was talk of the cadillac srx or whatever it's called having the same type of fan, and people using it with good results, but I think it was stand alone controllers and the threads are 3 plus years old.
some doc I was able to find. I did check the c6 output, it's the 128hz but with the fan unpluged the ecm doesn't output anything on the signal wire, so i still don't know what the other options in hptuners puts out. if you change the hz, it does do that. so seems like the stock gm brushless fans will work. just maybe not the aftermarket spal fans.
I wonder what kinda feedback the ecm gets to know it's not plugged into to the controller. oh and a pwm duty cycle of 9% was max speed and high duty was low speed. I have the exact numbers saved on the laptop. the stock brushed c6 fan pulled 32 amps for just a sec during ramp up but only 27amps at the max 90% on hp.
now if I could find a nice gm brushless fan that fits our radiators. the 850watt ats/cts-v looks way to big. maybe the dual out of a Chevy volt would fit and cheap. but I don't know their ratings, but only requires a 30amp fuse each, sure should loud thou at max. the c7 upgrade 600watt fan shows a 80amp fuse, can't find the blade size thou the stock c6 fan seems to be 16.5in blade. but they don't look like the brushed and brushless fans. mount to the motor the same.
The brushless fans from the cadillac srx are similar to the ones from the cts v/ vettes and newer camaros but the signal frequency they look for could be different (although i see no reason but I read on lateral-g that it could be 100 or 128 Hz)
Duty cycle should be 90% max (any higher is for diagnostic purposes).
I myself run a 500W brushless after market fan from spal (should be the same as the GM ones). Its installed as a pusher and I have a spal brushless fan sensor that sends the correct signal for it to run depending on engine temps. What I found out was there are two types of those sensors (an old model and a new one) which send the signal in different ways.
Im planning to swap my dual puller fans for a cts v fan as it is 850 watts but will not run it off the pcm as my truck overheats at highway speeds and my E67 ecu doesnt have a way to let me control what mph to command the fans to turn off. With the brushed fan I have an over ride temp sensor that kicks in once temps are above a certain limit. I hope the spal brushless fan sensor I have will run the camaro fan without issues, if so then ill have the pcm control the pusher fan instead (mainly ac pressure control)
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