So not an overly complicated question, but one I'm not really sure how to attack.

I'm running dual 4th gen fans controlled by my Holley EFI. I recently switched from a Painless Wiring F5 controller. Previously, both came on together and I could set when they came on and how the speed ramped in. Now each works independently, and I can set on/off temps, but have no speed control.

Here's the question. How would you guys initially set the two fans to come on, and when to turn off? As of now, I have the first fan set to come on at 190, and turn off at 185. Secondary at 200 and 195. Dont have the miles yet to see how it works. I can say the new engine and new cooling system work great and I had NO cooling issues with the F5 controller, so I expect my cooling efficiency to be a product of how I set up the fans to work, as I know the fluid system/radiator itself work fine.

Obviously I can adjust as needed, and with summer coming up I'll really get to see how it works. What would YOU guys do? Any logic as to why? Would you run both fans at the same temps?

 

Normally a duel fan functions if you have A/C.
The first fan is run without A/C on the inlet side of the radiator and should maintain engine temperature.
When the A/C compressor kicks on and the high side pressure reaches a pressure set point the second fan turns on to keep the engine temperature in a normal range.
If you don't have A/C, set both to come on/off at the same. If engine temperature is low install a hotter thermostat.

 

yeah....I was wondering about just setting them both the same.... No AC anymore.

 

Then just do it to the on/off temps you like.

 

Yeah, I getcha....I just didn't know if anyone had any specific thoughts or ideas as to what or where I should set them at. I'll probably leave 'em as is for now.

Thanks,
Chris

 

I kinda do it like you specified with second fan comin in at a higher temp. But it depends what the rad system is capable of cooling to in the given ambient.

In summer months my car with both fans on would stay at 200 and sometimes 205-210 if idling in traffic. In winter and fall months when temp was low enough i could keep 1 fan on and never get above 185-190. I like to keep my water temps in that range generally. So staggering the fan on off i can maintain roughly that range in any condition.

If your system can cool effectively and have no problem maintaining a set temp in any ambient then doin both fans on and off around that desired temp may be ok. But it does tax the electrical system bit more. Or lower the second fan on temp closer to first to gradually start the cooling process. Like fan 1 on 190 off 185 fan 2 on 195 off 190. That would likely keep it 190 all time. Kinda have to play with it but staggered seems to be how factory does it with the 4th gens

 

I set stock fans to 195 on 185f off and it seems to help keep the operating temp to 200f. Most stock calibrations are 226f on .

 

Orr that's what I was looking for. A logic as to WHY you did what you did. I DO know my cooling system works very well. I had no problems keeping it at the 190 level last summer with the F5 controller. It ran off the temp sensor, but i didn't set it by temp. It had a min temp of 160, a max of 220, and you tuned it by percentage with the little pot switches. I can guess, but don't really know when they came on and off. ....and they were gradual too, with speed control. it worked VERY well....so I guess that's why I really never looked to close at the temps and what it was doing.

I simply don't want to let it get TOO hot, but don't wanna over tax the system for no reason.

for now we'll go with what I've got and see what happens