Fan On/Off settings for 180F thermostat?

[anguilla1980]

1969 Firebird, Pontiac 461ci stroker.

I run a 180* Stewart high flow thermostat with a high flow FlowKooler water pump. I have a Dakota Digital dual fan controller programmed currently as such for the dual Mishimoto fans on my Champion radiator:

Low: On@185 Off@180

High: On@190 Off@185

Today I am installing a new 15-10010 C&R racing radiator module (dual SPAL fans).

I just want to get everyone's take on if my fan on/off settings are optimal given my thermostat?

Thanks!!!!

[andrewb70]

I think with a 180 thermostat you will never get below 180, so the way you have it now, the low speed fan will never shut off, which is not good.

I would do:

Low: On@190 off@185
High: On@195 off@185

The logic being, why not use both fan to bring temps down as fast as possible.

You may have to fiddle around with these settings. I would also install some way of monitoring fan activity inside the car. This doesn't have to be permanent. Just wire in some temporary LED lights so you know when each fan is kicking on and off. Also keep in mind, that if your cooling system is working properly, there should not be a need for fans at highway speeds.

Andrew

[anguilla1980]

That's good logic I think, thank you very much for the suggestion!

[dontlifttoshift]

I have never set them up the same but here is my baseline for 180* thermostat.

Low on-190/ off-185

high on-195/ off 187

Then I adjust from there. If the first fan can't keep up on it's own, I will lower the on temps to 187 and 190. If the first fan does keep up I raise all the on/off 5 degrees and see how that goes. I also take temps while driving into account, if the car runs at 195 going down the road and is happy there, I adjust the fans so that they are not running in that situation.

Every car is different.

To Andrew's point. I would prefer the primary fan run longer (or continuously) and maintain a given temperature than to cycle both on/off

[anguilla1980]

Interesting.

Right now my high fan goes off but my low-speed one never does.

Question, does it matter which of the 2 fans is my primary (low)? Right now my passenger side fan is, my drivers is the secondary (high). I noticed that the water enters the radiator from the intake on the drivers side, so perhaps that should be the one that kicks on first? Or does it not matter and I'm totally over thinking that aspect?

Thanks!

[dontlifttoshift]

Are they both the same size? I try to use the larger fan for reserve if I can get away with it.

Same size? I'm not sure it matters, although an argument could be made either way, I don't think it matters when there is a second fan in reserve.

The way you are set right now, the low fan won't go off as its off point is right on the thermostat. Remember, the thermostat is there to control _minimum_ engine temperature.

[anguilla1980]

Both are identical so I won't worry then.



I went with dontlifttoshift's suggestion:

Low: On @ 190 Off @ 185
High: On @ 195 Off @ 187

I'll see how that works for me.