Question about Derale electric fan kit for Jeep Wrangler TJs

[Juggernaut]

Which manufacturer?

You know, anyone can throw a kit together with chinese parts and call themselves a "manufacturer".

I found a deal on craigslist for one of them there flexalite E fans. $100.

Fan is oem quality.

Controller= shit box leaking diarrhea

After much research, I discovered that the only purpose for a fan being there at all is to service the radiator, not the engine.

When you are traveling at 50 mph the ram air through the radiator is much higher than a fan could produce. In that state the fan should be off.

If you measure the water temp at the engine exit the fan will run at 50 mph.

The way the manufacturer suggests would make the fan operation a function of engine rpm.

The way I suggest, makes the fan operation a function of cooling necessity. The fan only operates when increased heat needs to be dissipated from the radiator.

In 80* F weather, idling my fan runs 20 sec on, 100 sec off.

When I'm moving above 15mph it stays off unless I rev the rpms up past 3500.

Over 30 mph it stays off 100% of the time.

Also, a fan will wear out faster the longer it operates continuously.
Think about it.

Flex a lite and Derale just to name 2 manufacturers that instruct to install near the upper hose entry to the radiator, others make a fitting to install in the thermostat housing. Oems measure temp at waterjacket temps not the lower radiator exit for fan control/OBD purposes.

My fans operate the same as yours and are not rpm dependent at all. They are generally off at highway speeds unless unload and only switch on and off otherwise to stabilize engine temps about 210 degrees as it should. Question for you: how is meauring the engine temp at the engine exit going to make the fan run at high speeds or rpm dependent with the programmable controller?

 

[freedom_in_4low]

Could it be possible to design an electric fan that mimics the flow numbers of the stock one?

food for thought, I was watching an episode of Engine Masters where they dyno tested the same engine with 5 different fan configurations - no fan, a clutch fan, a flex fan, a low profile fixed fan, and an old school fixed fan.

They rigged up a radiator and shroud to at least somewhat simulate real world conditions, but the radiator didn't have coolant flowing so I don't think the clutch fan would have been fully engaged since it was getting air at room temp.

The clutch fan reduced the peak engine output by 15hp which was the best of the group, and the old fixed fan took 30 vs the no fan pull!

I wish they'd have done a pull and held a constant engine speed to sort out the actual fan power vs inertial losses of spinning up the fan, but that wasn't really what they were after.

 

[jlpierce70]

Just revisiting this post.

Once I got the adjustable thermostat set correctly everything works great.

The only time I have issues is when I'm plowing snow and the snow blows/mists? in the air and cools the area around the temp sensor that I have by the upper hose of the radiator. So I have to use a switch to act as an override and turn the fan on even though the sensor thinks its really cold out.

 

[jlpierce70]

My original problem was probably a clogged radiator. Assuming the plow was blocking air flow and causing the issue was incorrect.
The plow blocking the air flow left the radiator to cool by itself without the help of air flow which it couldn't do because the limited capacity caused by the clogged radiator.

 

[Onlyoneromeo]

My original problem was probably a clogged radiator. Assuming the plow was blocking air flow and causing the issue was incorrect.
The plow blocking the air flow left the radiator to cool by itself without the help of air flow which it couldn't do because the limited capacity caused by the clogged radiator.

I know this is an old thread but I wanted to know if you are still running the electric fan setup and if you had to upgrade your alternator to deal with the extra pull of electricity when the fans are on. If so what alternator did you use?

 

[jlpierce70]

I do still have the electric fan. Once I got everything dialed in using a push in temp probe (also from Derale) in the radiator in place of the one that came with the kit and went with their adjustable thermostat it works great now.

I also used a circuit breaker that auto resets in place of the fuse that comes with the kit. I think someone in this thread recommend doing that. I've never had it trip the breaker but nice piece of mind that I don't have to worry about carrying extra fuses.

I'd recommend doing the adjustable thermostat right away. Maybe I'm anal but I had the original kit wired in using all the correct wire colors and then when I changed to the adjustable thermostat the new kit used the same colors of wires in different ways so my wires now don't match the colors the instructions say they should be because I wasn't going to rerun all that stuff again. Not a big deal but if anyone else down the road is tracing the wires to solve a problem they are going to wonder what the hell didn't I use the right colors for the right things when he had them all? The adjustable is a negative switched system instead of cutting the power to the fan so just easier to do it right away rather than change stuff. OCD I guess. Ignore that paragraph...

I also added a override switch to turn the fan on manually. I found that when I plowed the snow "dust" would get into the radiator and make the probe think it was a lot cooler than it actually was and the Jeep would get warm. I never use the fog lights so I popped that switch out and switched it with one for the fan.

I didn't have to upgrade the alternator, the fan does run that long or much so its not a burden on the battery to the point that the alternator couldn't keep up.

https://www.amazon.com/gp/product/B000CNAMMQ/?tag=wranglerorg-20

https://www.amazon.com/gp/product/B004XONWT0/?tag=wranglerorg-20

https://www.amazon.com/gp/product/B01N4D04LS/?tag=wranglerorg-20

https://pin.it/45aE7be

 

[Juggernaut]

I know this is an old thread but I wanted to know if you are still running the electric fan setup and if you had to upgrade your alternator to deal with the extra pull of electricity when the fans are on. If so what alternator did you use?

This question wasn't directed at me, but I'm still running a Derale electric fan kit 20161 going on 5 years. It draws roughly 25 amps and I am running the original oem alternator and there is no need to upgrade even with my significant period correct/TJ approved Hella light setup @AndyG .

 

[AndyG]

This question wasn't directed at me, but I'm still running a Derale electric fan kit 20161 going on 5 years. It draws roughly 25 amps and I am running the original oem alternator and there is no need to upgrade even with my significant period correct/TJ approved Hella light setup @AndyG .

See this is great...

If everybody would do like this... And get their build permit... And submit their plans ... They could do anything they want to their TJ... As long as we approve.... And it passes inspection.

And everybody needs to remember if it's pre-2000 and you're going Period Correct you have to go before the historical board also.

And please don't gripe at me.... I just work here.

 

[Juggernaut]

I still suggest running the auto reset breaker and buy the adjustable thermostats as the one included with the kit allows the fan to run almost continuously due to the pre set temp setting. If your considering the install, a few tips are keep your wire runs short, size any additional wires on the larger side, size your ground ring terminals for your wires and amperage, and solder/heat shrink connections. Generally good electrical practices go a long way towards keeping the draw down. I know too many people who routinely pop fuses, melt relays and it's almost always the poor installation.