PWM radiator fan controller

[parsonsj]

For fun, I downloaded a ZR1 tune for MY 2011 with some mods, including the same injectors I'm running.

It has a bunch of segments my GMPP tune doesn't have. What I don't know, and what I wish I could get some guidance on, is how different the ZR1 tune is from the LS9 GMPP. I know that the GMPP tune doesn't have after-cat O2 sensors. Is there anything else?

I guess my concern is that by getting support for the pwm fans in a later OEM passenger car tune, will I end up with a bunch of other stuff that will cause me more trouble down the road?

Another question: how do I deal with the VIN number?

[RPOWU8]

Hi,

Have you tried changing the fan State vs Desired % and the control output vs State? Below is my 09 corvette settings. I am currently running a 2014 Corvette pwm spal fan on the 09 with no issues. Just needed to change Hz to 100. No controller needed with the newest spal fans, PWM signal goes straight from ECM to fan pwm input. Controller is built into fan

I am looking at adding PWM to my 11 CTS-V which uses discrete fan control and three relays. Going to use my 09 fan controller to drive the stock CTS-V fans. Waiting on fan pigtails to come in. I should be able to hook this up without altering any factory wires or connectors, just pull the fan 1 relay and use a pin to connect the pwm signal from the ecm to the pwm pin on the fan controller.

The fan state settings are quite different from the Corvette pwm to the CTSV discrete settings. Maybe the problem is there?

09 Corvette Base fan settings:


DJ

[parsonsj]

Hey DJ,

I've tried similar settings (based on my 07 Z06), but that pwm frequency is very interesting. I've always used 128 Hz (as recommended by HP Tuners), but have never tried 100 Hz. I'll post up my tables.

[RPOWU8]

The only reason I changed the Hz was for the new 2014 Corvette Spal brushless fan calls for a 100Hz signal. If you are still using the stock fan controller stick with the 128Hz. 128 Hz drives the new brushless fan fine as well but you would need to adjust the desired fan %. With the brushless spal and 128Hz, the fan is at max rpm at 70%. With a 100Hz signal, it takes 90% to max the fan out.

The spal brushless fans have the controller built right in the back of the fan.

Hope that makes sense?

DJ

[parsonsj]

Here's my config, just pulled from the tune file. My understanding is the State Transition and Output Control tables only mean something in Discrete mode, where the two fans can be set up to come on at various temps.

[parsonsj]

Yes, I get the difference in frequency for the different fans. I tried 100 Hz just now for fun. No joy.

This isn't a tuning issue, I don't think. GM disabled pwm fan control on purpose on the crate motor offerings. It's not clear to me if that was done in the ECU, or in the OS.

Hedging my bets, I have a 2011 E67 (originally off a V6 Malibu) on its way to a fellow in Austin who is upgrading the VIN and OS to a 2011 ZR1. From there, I can transfer my LS9 tune to that setup, and then I'll have my fan control. It's been an expensive and frustrating lesson... I was told this would work, but it doesn't. Not with the crate motors.

Oh, and one more thing: I've had two tuners tell me that the C6 controllers are problematic, and that the smart guys upgrade their controllers to high quality solid state relays. So I put all this work and money into getting to the C6 controllers, and that might not be the best destination!

[RPOWU8]

Its a shame if GM left this out of their crate engine stuff. Hopefully the new ecm and OS will shed some light on this for you.

When I get the CTSV working I will post the settings up. I have not found anyone to confirm that they have been able to make it work at this point, but really want to have the fans working with pwm.

Thanks to everyone for sharing their findings.

DJ

[andrewb70]

Regarding the C6 fan controllers, what I heard is that problems occur if an unknowing tuner demands 100% duty cycle. I guess time will tell how mine holds up. As it is, my fan rarely goes over 70%.

Andrew

[parsonsj]

90% max, eh? Good tip!

My approach is to get all this working with the C6 controllers, and go to a solid state relay if those controllers fail.

[RPOWU8]

I drag race my Corvette several times a month and use the caspers manual fan controller all the time. I probably run the fan for at least two hours cooling the car off at the track. I have never had a controller go bad but I have burned up the connector at the shroud twice before I bypassed that connector. Have not had a problem since I rewired it. Never been programmed over 90%. I ran the Dual spal fans for about three years. I pulled the connector at the controller several times and no problems with that connection.

I ordered a Crydom D1D20 SSR to test out on my small tranny cooler fan.

DJ

[parsonsj]

New information tonight is that the ECU doesn't read the AC pressure sensor even when it's connected. So my backup plan of using the fans in dual discrete mode (which I have working) won't support the AC input.

My new backup plan is a stand-alone controller. Derale has one that might be ok.

[parsonsj]

On the idea of a standalone controller, does anybody have a line on the voltage vs pressure map of the GM AC refrigerant sensor? (AC Delco pn 15-51258)

I've done some googling without much luck...

[andrewb70]

On the idea of a standalone controller, does anybody have a line on the voltage vs pressure map of the GM AC refrigerant sensor? (AC Delco pn 15-51258)

I've done some googling without much luck...

John,

If you know the max pressure reading of the sensor, then you can plot the output curve. From what I have seen (at least with the 5v oil pressure sensors) the output will be linear from .5 to 4.5 volts (.5 volts =0, 4.5 volts = max). You can verify this with your air compressor to a certain point.

Andrew

[parsonsj]

Andrew, that's good info. I can actually gather that from the car, using a DMM and gauge set.

[parsonsj]

So I did just that:

[andrewb70]

Looks linear to me, except for the 4.2v datum.

Andrew

[parsonsj]

My guess: that's a gauge problem. My compressor cycles off a little above that, 375 or so on the gauge. Vintage Air says their binary switch cycles the compressor off at 406.

[TBART70]

Deralle
has no switched ignition. It relies on the temp going down to turn off. It also wants you to put the probe in the cold side lower radiator. I had it there and with the adjustment I could not get the fans on. I put it in the hot side and adjusted it. Car runs 180 now. I am adding a time delay relay to shut off the sensor at 3 minutes ignition off.

[parsonsj]

I was going to connect the Derale via relays driven by switched ignition, but that's still a backup plan.

[TBART70]

Found out that the time delay relay needs to have 12 volts going through the accessory side to work. I will have to put a high amp relay in and use the time delay to control it. I wanted it to control the sensor but it has 5 volt reference which is not enough to power the capacitor.