engine fan thoughts electric vs stock

[climberdan]

i got a 85 4runner with a 22re...has no fan currently and ill need to buy everything either way...what is better for mostly dd and some mild wheeling...dont plan on driving through any rivers either...thanks in advance for any responses

 

[moldman05]

I prefer mechanical fans unless impossible to use such as remote or rear mounted radiator. A clutch on fan is desirable for highway use. I can't understand how an electric fan is more energy effective when the electric is being generated by a belt driven alternator and transported through wires, switches , and relays which increase resistance as they get hotter . The most important part of the fan is a proper shroud so the round blade can pull air through a square or rectangle. I use a 7 blade steel mechanical fan without clutch on my trail rig cause I don't go fast enough to not to need a fan. My fan blade takes up less room than an electric motor and blade.

 

[Croatan_Kid]

I'm partial to electric fans myself. I'd think you would want to try and save as much power as possible with a 4 cylinder.

 

[John Fuller]

some pros and cons to look at:
electric fans: frees up little horse power+; engine heats up quicker in winter for faster heat+; cheaper to come by at bone yards usually+; cool better in hotter weather+ (at least on jeep 4.0), if both fail or one if that's all u got than ur screwed-.
clutch fans: little more drag on engine-; constant cooling no matter what on one side of radiator +, louder engine noise- lol, when mounted on water pumps...they shorten the life of the water pump bearings due to weight-,
in the end, i always choose electric dual setup on my xj just cause it keeps the jeep xj running way cooler and i love the quieter engine noise and easier to descipher engine bay noise without one lol.

 

[shawn]

I can't understand how an electric fan is more energy effective when the electric is being generated by a belt driven alternator and transported through wires, switches , and relays which increase resistance as they get hotter

It comes from drag racing, where they don't run an alternator. The fan runs off the battery, which gets charged in the pit after each run.

That translated over to the rest of the automotive world as "electric fans use less power".

But yeah, alternator makes heat, electric fan motor makes heat, wires and fuses and relays and connections all have resistance which... make heat. Heat is lost power.

Everybody that has an electric forgets to turn it on. With the way 22Rs warp heads.... well....

 

[karatejosh]

^^^ I forget to turn mine on all the time lol

 

[Jeff B]

I always forgot to turn mine on too..

 

[climberdan]

thanks for all the info guys!

 

[Tim C]

They both have pros and cons but it boils down to this: if you run electric set it up to automatically come on like a modern factory car, not just a toggle switch you have to remember, if you go mechanical fan use a shroud or you're wasting your time.

You can set up an electric automatic controller that will still have a switch for manual override off if need be, and have it set to turn on a reminder light.

If you run a mechanical fan the shroud needs to be within an inch of the blade tips and looking from the side the back half of the fan nearest the engine needs to be out of the shroud. Without doing that the fan looses efficiency badly.

I prefer mechanical but I set mine up like the crown Vic's did with an engine driven mechanical with a shroud and an electric fan inside the shroud between the mechanical fan and the radiator. At low crawling speeds the electric fan kicks on at 225* on high or low anytime the a/c is running. I have lots of room under hood though.

 

[Mac5005]

some pros and cons to look at:
electric fans: frees up little horse power+; engine heats up quicker in winter for faster heat+; cheaper to come by at bone yards usually+; cool better in hotter weather+ (at least on jeep 4.0), if both fail or one if that's all u got than ur screwed-.
clutch fans: little more drag on engine-; constant cooling no matter what on one side of radiator +, louder engine noise- lol, when mounted on water pumps...they shorten the life of the water pump bearings due to weight-,
in the end, i always choose electric dual setup on my xj just cause it keeps the jeep xj running way cooler and i love the quieter engine noise and easier to descipher engine bay noise without one lol.

BS.

Electric fans don't save that much hp. The good ones are high amperage that cause an increase in draw on the alternator, also causing premature wear on it. As mentioned above losing energy as heat in associated wiring.

Never seen an electric fan cheaper than a factory fan or clutch in a wrecking yard.

I don't believe they cool better as the Cfm of mechanical fan will be directly proportional to engine speed.

You say clutch fans are louder, and this is proving that mechanical fans have higher cfms.

The oems spend tons of time designing water pumps to hold the load of a spinning fan for hundreds of thousands of miles. They also invest the same in balancing the clutch and fan.

I've been through 3 electric fans in the last 6 years, while water pumps and fans last 100k miles and up.

The problem with mechanical fans is when they are spinning and are submerged in water. The fan pushing the water, pull the blades into the radiator. Another issue and mentioned above is that the shroud is extremely important.

E fans are simple and easy to mount, but will always fail first. The more complex the system to run the e fan, the more prone the system is for failure.

As well with an e-fan, when a relay fails, you don't know it's not running until you are over temp.

A mechanical fan even without clutch is far more efficient at moving the same Cfm of air, and far more dependable.

There is no free energy, it all has a cost. The more complex the system the more energy loss to generate the same flow.

As far as heating up in the winter, that's a bogus claim. The radiator size, thermostat, heater core size and air flow all play a part. This is when a fan with a clutch is desirable as it won't spin when cold.

Or if it's needed to warm up fast when cold, block the radiator with cardboard.

Same as leaving e-fan off.

I currently run an electric fan because I didn't have the distance to fit a mechanical fan between water pump and radiator.

I would switch to mechanical if I can.

@John Fuller, I'm no xj guy, but I thought the xj mechanical fan is driven off an idler pulley and not the water pump pulley. ?

If you have a mechanical fan that fits an xj waterpump bolt pattern, let me know how much, I'll buy it right now.

Temperature swings from hot to cold to hot to cold does damage.

An e-fan is great for keeping air moving in a hot engine bay with engine off and to cool engine down after shutoff.

The best solution? To each his own.

My .02

Mechanical fan with the proper clutch, or no clutch and maybe some supplemental small pusher electric fans for when running a/c and/or idling for long periods in the summer.

 

[krehel24]

This hurts my brain! You will not notice a HP difference with mechanical! It will not kill your water pump because of excessive weight! !! Smh!! Get what ever works for you best!! Its not a fawkng drag car!!

 

[jeepinmatt]

Electric fans actually do free up some HP regardless of if you guys believe it or not. The mechanical fans probably move something like 10000+ cfm, whether you need it or not, whereas the electric fan moves much less, and is usually sufficient for cooling. A thermal clutch on the mechanical fan helps alleviate some of this but not all. Also, the e-fan only accelerates once and then maintains speed based on supplied voltage, whereas the mechanical fan speeds up and slows down every time the engine speeds up and slows down (most clutches have a freewheeling action, but for some reason air creates a lot of drag for a fan).

The Taurus e-fans are pretty reliable and move something like 3000cfm, but also put a lot of load on your electrical system at about 30 amps (maybe even more on startup).

 

[Mac5005]

Electric fans actually do free up some HP regardless of if you guys believe it or not. The mechanical fans probably move something like 10000+ cfm, whether you need it or not, whereas the electric fan moves much less, and is usually sufficient for cooling. A thermal clutch on the mechanical fan helps alleviate some of this but not all. Also, the e-fan only accelerates once and then maintains speed based on supplied voltage, whereas the mechanical fan speeds up and slows down every time the engine speeds up and slows down (most clutches have a freewheeling action, but for some reason air creates a lot of drag for a fan).

The Taurus e-fans are pretty reliable and move something like 3000cfm, but also put a lot of load on your electrical system at about 30 amps (maybe even more on startup).

This is what I'm running. I've had constant problems with high speed with 40a continuous duty relays. Low speed is fine for sitting still but need high speed for the rowdy pedal. High speed always quits once engine gets over 220, right when you need it. It works while testing when under good temps are low but quits when the user hood temps go up.

Been through 3 Taurus fans since 06. Vary from $40-$75 at junkyards.


When low cuts on, drops voltage on gauge from 12 to 10ish and Rpms drop slightly on startup.

High speed drops the volts closer to 9 when running and definitely draws the rpm down at idle due to alternator working harder.

I'm not arguing that a 3000 Cfm fan dconsumes less hp than a 10000 Cfm mechanical fan, I'm arguing that the cost of that is reliability.

The more hp you are using is directly equivalent to the fuel consumed, and also directly equivalent to heat produced.

So why would you want a constant Cfm fan when the heat input into the cooling system isn't constant.

Example :

Electric fan uses 10% less hp on a 150 hp motor.

Great, but how much does the fan cost? Wiring? Plus installing it?

How about time lost troubleshooting it, or cost to replace the head and gasket, mill the head flat? All due to a failed 10% hp saving.

And that 10% saving is only when the clutch fan is completely locked up, and you don't need the added Cfm.

A mechanical fan is great when vehicle speed is low and engine rpm is anything but idle.

An electric fan is great when at wide open throttle for freeing up some, but not a lot of HP.

Here my point in short version: which of those two scenarios is more like offroad driving.

At highway speeds, the air in through the grill exceeds both.

 

[Fabrik8]

If you want compete reliability, get a mechanical. If you want the control advantages of an electric (AC control, thermostat control, multiple speeds, etc) and the efficiency gains from having no engine load when the fan isn't running, get a electric. Electrics can do full cfm at low engine RPM, which is awesome.

 

[climberdan]

I really appreciate all this input...I've got a lot to consider...I currently have no fan, clutch or fan shroud at all. I have an aluminum radiator on the way this week and a possible basically free electric fan and a buddy to install. Sounds like for me mechanical would be the way to go, but in my rare case the electric will be actually cheaper. I may run electric for now and post results...when it breaks I'll switch to mechanical and that'll give me time to scavenge all the parts...thanks again...ton of great info on here from you all

 

[Mac5005]

Speedway motors has some cheap universal shrouds without a hole cutout. Figure out how to mount it and then cut out to match you fan.

Sometimes the shroud is the hard part to find.

I'm sure someone on here has a 22r fan they will sell.

 

[Fabrik8]

Its not a fawkng drag car!!

I don't know of many race cars that use mechanical, and they almost all run an alternator.

 

[Ron]

Mac, if your system voltage is dropping that much your alternator isnt big enough for your system. The low voltage is killing the e fans , as with any e motor low voltage is a killer.

The hp gain (albeit minimal) is because your alternator has to spin anyway for other systems . A volt regulator removes (or lowers) the excitation field current. It does not (significantly ) reduce the mechanical draw to turn the alternator.

Lots of folks want to throw efficiency laws at this and say since you turn an alternator that produces electricit to turn an e fan it must be less efficient than turning a m fan. The missing partner the equation is when you goto a m fan you don't get to eliminate the alternator. It still has to be there for other purposes.

 

[krehel24]

I don't know of many race cars that use mechanical, and they almost all run an alternator.

The drag car I work on has an electric fan on a switch, and a little electric motor that drives the water pump, no alternator at all. ..

Make sure you use a relay with the fan you are getting for free, if it doesn't come with one. If you need one, send me your address and I will ship one to you! (I have a bunch left over from a job I did! Free to me means free to you!)

 

[krehel24]

Btw, personally on my 4runner with a 22re I run a stock manual fan with an electric pusher on a switch for those really hot days when I am waiting on the trail plug!

 

[climberdan]

The drag car I work on has an electric fan on a switch, and a little electric motor that drives the water pump, no alternator at all. ..

Make sure you use a relay with the fan you are getting for free, if it doesn't come with one. If you need one, send me your address and I will ship one to you! (I have a bunch left over from a job I did! Free to me means free to you!)

thanks man!

 

[XJsavage]

If you can fit it, mechanical and forget it. A good Spal e fan is a nice addition. I ran a 16" Spal on my Griffin radiator in my last rig. I had it set up two different ways.
1. Fan set to cut on by a preset 185 degree sending unit (negative relay) tapped into my water pump housing.
2. Fan on toggle switch, 40 amp, off and on and used the 185 sending unit as a trip for a interior light to let me know when the engine was getting to temp.

With that one fan off-road my 6.0 never got warmer than 185. I'd leave it on the whole time usually. Driving down the road, it'd stay in the same range with no fan whatsoever.
Invest in a really good radiator and you'll have a lot easier time keeping stuff cool.

 

[climberdan]

If you can fit it, mechanical and forget it. A good Spal e fan is a nice addition. I ran a 16" Spal on my Griffin radiator in my last rig. I had it set up two different ways.
1. Fan set to cut on by a preset 185 degree sending unit (negative relay) tapped into my water pump housing.
2. Fan on toggle switch, 40 amp, off and on and used the 185 sending unit as a trip for a interior light to let me know when the engine was getting to temp.

With that one fan off-road my 6.0 never got warmer than 185. I'd leave it on the whole time usually. Driving down the road, it'd stay in the same range with no fan whatsoever.
Invest in a really good radiator and you'll have a lot easier time keeping stuff cool.

I got the best radiator I could afford...200 bucks, all aluminum racing one made in japan...didn't have the budget for a 400 or 500 dollar one

 

[Caver Dave]

Mac, if your system voltage is dropping that much your alternator isnt big enough for your system. The low voltage is killing the e fans , as with any e motor low voltage is a killer.

Ditto!

I've had constant problems with high speed with 40a continuous duty relays.

I believe the specs for Taurus fans High side in-rush/startup draw is closer to 70A and might explain the lack of longevity? (Disclaimer: depending on what source you choose to believe)

I've done 4 e-fan conversions (5th will be my brothers CJ soon)... ALL using Taurus/Mk8 fans... ALL running 130-140A alts... ALL using parallel 40A-50A GM relays on the high side. Basically, duplicated the fan & charging that came factory on eleventy-zillion of those little POSs (Taurus/Contour), the GM relays are beefy ($1.50ea w/ socket at PaP) and the relay config is stoopid bulletproof (single for low, dual/parallel for high & a lockout between the speeds, so they can't both be energized simultaneously = let's the smoke outta the fans)
To date, no failures (doesn't include the 100% manual operation required in the Jeep... that's forgotten often )

Sorry, but there's never been a waterpump last "hundreds of thousands of miles" with or without a mech fan attached!

 

[Fabrik8]

I believe the specs for Taurus fans High side in-rush/startup draw is closer to 70A and might explain the lack of longevity?

The relay inrush current specs are usually much higher than that, usually 3 or 4 times the constant load current rating. Disconnecting a high current inductive load is pretty brutal, usually much worse than connecting. Depends if the fan or relay has flyback/clamp diode built-in to clamp inductive kick.