Lowering fan activation temps
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Joined: Feb 2019
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From: Los Angeles
Lowering fan activation temps
Long story short, I'm going to be taking my 02 C5Z to the tuner on Friday to tune out the 2mph fuel cut off since it has been giving me nothing but problems and I have already exhausted all other options. Since I'm bringing it in and buying an HP Tuner credit, I'd also like to lower the fan activation temps especially with summer being here.
I know the low fan turns on at 226 and the high at 235. Not sure when they both turn off.
I'm thinking about just lowering everything by 10 degrees across the board. The car is all stock so I don't need any insane cooling but I need something sustainable since I plan to be driving this car a lot.
Wondering if lowering everything by 10 degrees is good enough?
Thanks
I know the low fan turns on at 226 and the high at 235. Not sure when they both turn off.
I'm thinking about just lowering everything by 10 degrees across the board. The car is all stock so I don't need any insane cooling but I need something sustainable since I plan to be driving this car a lot.
Wondering if lowering everything by 10 degrees is good enough?
Thanks
Last edited by 1190405; Jul 17, 2019 at 05:49 PM.
Drifting
Joined: Jul 2015
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From: San Jose, CA
The factory temperatures are sustainable. Stock car, stock temperatures. If you don't like the temperatures, though, you probably won't run into any problems aiming for about 190F steady-state and trying to pin the top-end to 212F, so just set those points to turn the fans on (and about 10-15F lower to turn them off.)
Melting Slicks
Joined: Feb 2001
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From: Northville, MI
I never look at the water temp, to me the oil temp is the critical one, for street driving mine seldom goes over 217 degrees and when taking back to back autocross runs or on the HPDE course I keep it under 260 degrees. When ever I think to look at the analog water it is usuall about 230-236 degrees. If I am on a 20 minute HPDE run My oil might reach 275-280 at the end. All are withing good margins for the engine. If you really want to cool the oil/water temps put down the windows and with the fan on low turn on the heat--cools faster than AC fans. However my tune turns the fans on earlier than the stock settings (not that worried about mpg)
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So I just got back from the shop and got him to turn off the VATS, adjust the fuel cut off to 256mph and lower the fan temps by 10 degrees across the board. I already have a CAGS kit and I know I coulda asked him to hit that button anyway but they were super busy and so I didn't wanna pester them.
I took a pic of the screen showing the new fan temps and noticed that for FAN #1, "Enable Speed" is set to 30mph and "Disable Speed" is set to 35mph.
I don't think he touched these.....but does this mean my low fan won't turn on at all until 30mph? Is that normal?
Last edited by 1190405; Jul 19, 2019 at 08:37 PM.
Instructor
Joined: Jan 2014
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From: Vegas NV
So I just got back from the shop and got him to turn off the VATS, adjust the fuel cut off to 256mph and lower the fan temps by 10 degrees across the board. I already have a CAGS kit and I know I coulda asked him to hit that button anyway but they were super busy and so I didn't wanna pester them.
I took a pic of the screen showing the new fan temps and noticed that for FAN #1, "Enable Speed" is set to 30mph and "Disable Speed" is set to 35mph.
I don't think he touched these.....but does this mean my low fan won't turn on at all until 30mph? Is that normal?
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Drifting
Joined: May 2007
Posts: 1,550
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From: Mid Ohio
I have ford tuning experience... taking stock numbers and changing them by a percentage is a good way to stay safe and dial in. So for fans something like 10% decrease would look like 227F * 0.9 = 204F & 235F = 212F
Just make sure they don't conflict with other commands (like auto tranny up/down shift points & converter lock)
Just make sure they don't conflict with other commands (like auto tranny up/down shift points & converter lock)
Melting Slicks
Joined: Jan 2009
Posts: 3,275
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From: Miami FL
It says Fan1 and Fan2 as if in Low Speed mode only 1 fan is active and then the 2nd fan is added up in High Speed. Actually Fan1 means Low Speed (both fans together, but at half the speed) and Fan2 means High Speed (both fans together, at full speed).
The Disable Speed and Enable Speed means that fans will turn ON following the preset temperature thresholds, as long as you're below 35MPH (the Disable Speed). If you cross that threshold they will turn OFF regardless of temperature and will remain OFF as long as you're above 30MPH (the Enable Speed). As soon as you drop below 30MPH fans will revert to follow the preset temperature thresholds.
In other words, there is a 5MPH cushion much like the way thermostats work.
Last edited by GCG; Jul 26, 2019 at 11:48 AM.
Drifting
Joined: Jul 2015
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From: San Jose, CA
GCG makes everything clear 
This behavior is also called hysteresis. It avoids the problem of you going precisely (eg) 35mph and the fans clicking on-off-on-off-on-off rapidly.
Same reason for the temperature on/off points being different. Avoids the problem of your water temps going to 225F and your fans clicking on-off-on-off constantly.
I only add this because precise terms make it way easier to google things for better understanding.
This behavior is also called hysteresis. It avoids the problem of you going precisely (eg) 35mph and the fans clicking on-off-on-off-on-off rapidly.
Same reason for the temperature on/off points being different. Avoids the problem of your water temps going to 225F and your fans clicking on-off-on-off constantly.
I only add this because precise terms make it way easier to google things for better understanding.
Melting Slicks
Joined: Jan 2009
Posts: 3,275
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From: Miami FL
Thread Starter
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Joined: Feb 2019
Posts: 99
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From: Los Angeles
No, that's not what it means. The wording is not clear and labels are a bit misleading.
It says Fan1 and Fan2 as if in Low Speed mode only 1 fan is active and then the 2nd fan is added up in High Speed. Actually Fan1 means Low Speed (both fans together, but at half the speed) and Fan2 means High Speed (both fans together, at full speed).
The Disable Speed and Enable Speed means that fans will turn ON following the preset temperature thresholds, as long as you're below 35MPH (the Disable Speed). If you cross that threshold they will turn OFF regardless of temperature and will remain OFF as long as you're above 30MPH (the Enable Speed). As soon as you drop below 30MPH fans will revert to follow the preset temperature thresholds.
In other words, there is a 5MPH cushion much like the way thermostats work.
It says Fan1 and Fan2 as if in Low Speed mode only 1 fan is active and then the 2nd fan is added up in High Speed. Actually Fan1 means Low Speed (both fans together, but at half the speed) and Fan2 means High Speed (both fans together, at full speed).
The Disable Speed and Enable Speed means that fans will turn ON following the preset temperature thresholds, as long as you're below 35MPH (the Disable Speed). If you cross that threshold they will turn OFF regardless of temperature and will remain OFF as long as you're above 30MPH (the Enable Speed). As soon as you drop below 30MPH fans will revert to follow the preset temperature thresholds.
In other words, there is a 5MPH cushion much like the way thermostats work.
GCG makes everything clear
This behavior is also called hysteresis. It avoids the problem of you going precisely (eg) 35mph and the fans clicking on-off-on-off-on-off rapidly.
Same reason for the temperature on/off points being different. Avoids the problem of your water temps going to 225F and your fans clicking on-off-on-off constantly.
I only add this because precise terms make it way easier to google things for better understanding.
This behavior is also called hysteresis. It avoids the problem of you going precisely (eg) 35mph and the fans clicking on-off-on-off-on-off rapidly.
Same reason for the temperature on/off points being different. Avoids the problem of your water temps going to 225F and your fans clicking on-off-on-off constantly.
I only add this because precise terms make it way easier to google things for better understanding.