99xj2.5

I've been wanting to put Taurus fans in my rig for a while now and have seen lots of specs and info on the fans themselves but not on how to set temp controlled. I read something about someone having dual fans that were separately controlled by the ECM to turn on and off at certain temps but couldn't find any info on how to do it. And if not ECM controlled then how? (and just using manual switches and keeping an eye on the temp gauge is out.......idiot lights)

-matt-

TrekkerJmm

Hi. All you need to do is have one fan on all the time and the other one hooked where the factory E-fan is hooked to. Also refer to this URL...Tj
http://go.jeep-xj.info/HowtoTaurusFanInstall1.htm

UserID6095

Run a variable controller and forget about it.

99xj2.5

How does a variable controller work?

blasto9000

Variable fan speed is unnecessary. The controllers are bulky, require careful mounting (they get hot and need to be cooled themselves) and are another part to break! SPAL had them about 6-8 years ago but turned out to be problematic. Having used them before I would just go with a temp switch. Don’t use the ones that you shove through the radiator fins though… they vibrate through the cooling rows eventually and then assasinate you when you’re out in the middle of nowhere. ;-)

Dozens of vehicles used fan switches that directly contact the coolant, either mounted in the radiator, thermostat housing, cylinder head, etc. Use an OE switch like this and make sure it’s installed IN the coolant stream. If it’s not IN the coolant stream it’s worthless.

Also, do not leave an electric fan running full-time. The motors have a limited service life and if you leave it running all the time you won’t get many miles out of it before it fails.

Most of the current crop of aftermarket ECMs control the fans based on the ECT sensor. They are ON/OFF only, not variable. There may be a stock cooling fan output on a later model Jeep ECM, but I suspect that would be only for the A/C fan.

Having said that, I would just stick with the clutched mechanical fan and shroud. This is really a proven performer, very reliable, and still used on modern high-end vehicles like BMW X series, Mercedes ML, Land Rover, Lexus RWD cars and pretty much any RWD-based vehicle.

99xj2.5

I'd agree with you that leaving my mechanical fan on would be easier, but I have a four cylinder and I'm trying to get more out of it, which is why I'm trying to figure out the whole electric fan thing.

blasto9000

Yeah, I definitely feel you. But I don’t think the electric fan is going to gain you anything. It’s tough to find an electric than can flow enough air to be the sole cooling fan. And they use just as much power as the mechanical, which puts more drag on the alternator. (No such thing as a free lunch.)

About 20 years ago I did back-to-back dyno runs on my ’68 Cougar with an electric fan and the stock mechanical fan. Granted, it’s a different beast than the Cherokee, but the principles are the same. One thing about the electric fan (probably exacerbated by running the car in a dyno room) was that it allowed the engine to heat-soak a lot faster than the mechanical, and it took longer for the electric to bring the temp back down, so the car actually lost about 9 hp on the high RPM end. (The car was only making 200 whp so 9 hp is fairly significant, around 4.5%.)

I also horsed around with the electric driven water pumps and this cooling system “system” by Fluidyne a few years ago. The Fluidyne system used a variable speed water pump and fan to attempt to hold the cooling system temp at a constant user-setting from 160 to 200 degrees F. It wasn’t very reliable and never was able to hold the temp. And it was expensive, over $600 all told. In the end I figured $600 would better be spent elsewhere, and “perfecting” the cooling system just wasn’t something possible with a regular air-water cooling system.

Mechanical fan isn’t very romantic. But it’s an old reliable and outperforms anything else I have tried.

HCCAFan

blasto, are you saying not to even bother with any fan upgrades? My XJ got hot the other day from idling too long. It seems the temp goes up whenever I'm not in motion which tells me I have a fan problem but both my stock fans seem to work normal. I have been thinking about the taurus fan myself so I can either flip a switch when the temp starts going up or do like you said and put an OEM temp switch in the upper hose.

blasto9000

Based on my experience, yes. Adding an electric fan to the stock mechanical is probably fine, but don’t forget it still takes power to run. And electric fans induce a lot of vibration so they should be carefully mounted.

If it’s a new overheating problem you’re having I guess I’d replace the stock fan clutch as a first step.

UserID6095

Not sure where you are getting your info but the high end cars you mentioned have not used mech fans for years.

As for the Cougar story, well that was 20 years ago. An e-fan back then was not built the same as one today. Modern e-fan will pull more air then our stock fan clutch setup.

The taurus fan is a factory two speed fan. You can wire it in as so or use a variable speed controller.

Lastly yes, ditching the mech fan will give you more power. They tend to rob quite a bit when they fully lock up.

HCCAFan

OK

1991Jeep_Man

Uh, I disagree with all of your info except the bit about what temp switch to use. If e-fans are so un-reliable and such, then why does my uncle run a dual fan set-up on his 71 Drag Camaro with nitrous shot bored 60 over and Lord knows what else done to it?? Why do 99% of modern vehicles have e-fans? Why are there e-fan kits for nearly every vehicle now to replace the power robbing engine driven fan?

Also, where do you get the knowledge on the alternator? The alternator has no variable energy output... when it spins, it spins. Drawing more energy doesnt make the alt draw anymore power from the engine than before. Granted you may not have enough charging ability with too many upgrades, but otherwise the alt just spins at whatever speed the engine is spinning.

To the OP, GO FOR IT. The e-fan upgrade is well worth it, especially if you go crawlin where low RPM's will cook your engine.

Hommersimpson

parts stores sell a switch for about 21 bucks.. has a thing that sticks in radiator core.. you have a dial.. and wire it into fan... you set it to what ever temp you want it to come on.. i cant think of name of it.. but every parts store has them...

HCCAFan

^You talking about the thing he said not to stick in the fins cause it will wear a hole in the radiator?

99xj2.5

does anyone have a wiring diagram for how they set up their fans? I get how to mount the fans but the wiring and switches still are confusing me.