Cooling Stack Fan control
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Staging Lane
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Cooling Stack Fan control So educate me on how a person would set up the fan control on a cooling system with radiator, AC and a supercharger intercooler and also controlling the pumps. This will be a GM controller set up with 2 fan leads, one comes on at 97c and the other at 105c. Looking at the pinout I can't see anything for PWM control, it's on or off and guess the supercharger pumps just run at one speed when the engine starts. I don't see there would be any need to run the fans probably at highway speed, but an AC trinary switch would likely run the fans when the system pressure calls for it regardless of the water temperature in the cooling system. Is the intercooler just ignored and not part of the control system for the fans?
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Thread Starter
Staging Lane
Joined: Feb 2021
Posts: 60
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Thread Starter
Staging Lane
Joined: Feb 2021
Posts: 60
Likes: 10
https://www.chevrolet.com/content/da...n-19370666.pdf
Would prefer not to have the fans running cruising down the road with AC on at say 70mph if they don't need to be on. Not sure how to set that up though.
Would prefer not to have the fans running cruising down the road with AC on at say 70mph if they don't need to be on. Not sure how to set that up though.
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https://www.chevrolet.com/content/da...n-19370666.pdf
Would prefer not to have the fans running cruising down the road with AC on at say 70mph if they don't need to be on. Not sure how to set that up though.
Would prefer not to have the fans running cruising down the road with AC on at say 70mph if they don't need to be on. Not sure how to set that up though.
Your system turns on two fans based on temperature as you already said. The relays are already included. If the highway speed air is enough to cool the engine down below 207F, the fans will be off.
There is no consideration for air conditioning that I could find in the documentation. You would have to wire in your own bypass for that. It's not difficult. You could drive an extra set of fan relay(s) off the compressor clutch circuit. That way, either the ECU or the A/C clutch turns on the fan(s). However, at highway speed, they will stay on if the A/C is on.
Your supercharger cooling pump appears to be on full tilt all the time. My guess is that you should not change this without careful consideration. Let's say you rig some setup to cut this off at highway speed (It could be done but not simple). Then you decide to floor it on the highway, you're charge temp may be too high and you may detonate. There may be other design reasons why this may need to be on that I'm not aware of.
If you still wanted to rig some setup that would override the supercharger pump, I would think that you would want to drive it off the charge temp sensor. A PWM setup could be done where the charge temp controls how hard the supercharger cooling pump is PWMd so maybe at highway speed or in the winter, this pump does not run as hard or at all.
Last edited by LSswap; Jul 3, 2021 at 07:50 AM.
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Staging Lane
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Definitely plan to leave the supercharger pump run continuously, like you said too much risk not doing that. Doing some searching I found this switch in this link for the AC circuit which I can use on both fans. It turns fans on when the AC high side pressure hits 256 psi https://www.summitracing.com/parts/v...w_wcB#overview. I haven't purchased the AC yet, probably need to specify this when I order it or add it on. Here's their video on how to wire it https://www.vintageair.com/tech-vide...rinary-switch/
Last edited by srode1; Jul 10, 2021 at 04:13 AM.
Do you know if the fan control output on the E99 ECU is a ground signal or for a PWM? You may want to check that before you buy a fan. I'm working on installing a C7 fan now on my 68 Camaro which uses PWM.
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Staging Lane
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"Two cooling fans are controlled by the ECM. Control is set to turn on the first a 12 V fan at 97 Deg C (207 Deg F) coolant temperature and the second fan at 105 Deg C (221 Deg F). The fan control wires are fused/relayed and can be connected directly to the fans."
From the documentation - which I read as on / off, not PWM but could be wrong. Odd they aren't ground though, I would have thought as on / off they would be, not fused and relayed. Hmmmm
"Two cooling fans are controlled by the ECM. Control is set to turn on the first a 12 V fan at 97 Deg C (207 Deg F) coolant temperature and the second fan at 105 Deg C (221 Deg F). The fan control wires are fused/relayed and can be connected directly to the fans."
"Two cooling fans are controlled by the ECM. Control is set to turn on the first a 12 V fan at 97 Deg C (207 Deg F) coolant temperature and the second fan at 105 Deg C (221 Deg F). The fan control wires are fused/relayed and can be connected directly to the fans."
Andrew
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Staging Lane
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I talked with a technical assistance person at GMPP today and found this fan control system is not PWM, its on/off and the leads are positive not ground. So each wire runs to each of the fans, then each fan is grounded. Easy run an additional power feed to the fans from the Vintage Air trinary switch then and won't cause any problems with the controller.
Steve
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I talked with a technical assistance person at GMPP today and found this fan control system is not PWM, its on/off and the leads are positive not ground. So each wire runs to each of the fans, then each fan is grounded. Easy run an additional power feed to the fans from the Vintage Air trinary switch then and won't cause any problems with the controller.
Steve
Steve
thanks Andrew,
I talked with a technical assistance person at GMPP today and found this fan control system is not PWM, its on/off and the leads are positive not ground. So each wire runs to each of the fans, then each fan is grounded. Easy run an additional power feed to the fans from the Vintage Air trinary switch then and won't cause any problems with the controller.
Steve
I talked with a technical assistance person at GMPP today and found this fan control system is not PWM, its on/off and the leads are positive not ground. So each wire runs to each of the fans, then each fan is grounded. Easy run an additional power feed to the fans from the Vintage Air trinary switch then and won't cause any problems with the controller.
Steve
Andrew
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Staging Lane
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Interesting, I didn't realize the OEM PWM signal came through the ground wire- so no relay involved?
Guess the GMPP controller is set up differently to make integration into project cars easier. So I guess I can run the AC trinary from Vintage air to the ground side of the fan relays in the fuse center instead of using separate relays for it?
Guess the GMPP controller is set up differently to make integration into project cars easier. So I guess I can run the AC trinary from Vintage air to the ground side of the fan relays in the fuse center instead of using separate relays for it?