Maddog

I went to a local 4wd parts & accessories place today,& asked them about a electric fan,the had a twin fan unit (second Hand) for $80 (about $35-40 US).Which should bolt straight up ,he said i could just wire it to a switch & have it running all the time if i wished or at least around the city traffic.
What to u think?
I know you guys like the Tuarus fan but we dont have them here.
Also the hottest we get here in summer is about 31 degrees centigrade.
At the end of the day im pretty keen to get rid of the stock one, I hear it weighs a tone.

Sunday BBQ

I, too, and very interested in this. I didn't plan on doing the Taurus thing, I was just going to buy a generic fan from autozone or something. Anyway....

BLKNBLU

iTrader: (1)

Thats 85-90 degrees to us farenheit jokers. Sorry, got no experience with the fan, but a straight bolt on sounds good to me. Here in Arizona U.S.A, I could just turn it on and forget about it.

Robinhood150

Why do you want to get rid of the stock one? I think it works fine. If I were to do it again, I don't think I would switch to the taurus fan...I have noticed no difference in mileage and little if any difference in power. I'd stick to the reliability of the stock one.

Wiring to a switch would work, but there are disadvantages to this. The most important is that you could forget to turn it on and your engine will overheat. Bye bye engine, or at least headgasket. Also, if it's on all the time, I'd bet you get less mileage than with the stock fan. Energy isn't free ya know.

Maddog

I dissagree,the stock one is very heavy i believe,& i can feel it fighting me first we drive after start up.All my driving is around the suburbs & city so a start & stop alot.i think not having to use the motor to drive the fan, will make it a little easy on the motor.Running a electric fan of the battery will not effect gas mileage at all,the battery has more than enough juice to run it.So it is completely seperate to the motor,
Also the switch would be on by default so there is no danger of forgetting.the plan being that once the ignition is turned on the fan will start.

Robinhood150

An electric fan does not get free energy, it has to have energy from somewhere and it gets it from the alternator. When you have more of an electrical load the alternator has to work harder which makes your engine work harder. It's not physically connected to the engine, but it is connected by energy. If you hook up a 5hp electrical motor to the battery to run a widget, then you're using 5hp plus electrical losses from the engine. It's a basic law of thermodynamics.

When the engine is not hot the clutch almost totally disengages the fan and puts little load on the engine. So in other words, when it's not needed, the fan doesn't do anything. One way to test the stock fan clutch is to tie a kite string to the fan and upon start up from cold, the string should not break. It can't be using much energy if a kite string can hold it.

I will concede that you may feel the engine rev up faster...I think I did, but that could be in my head.

Maddog

bump bump
Anyone else or do you agree with robin hood,I know what he's trying to say but we will have to agree to disagree

Robinhood150

grams72

Could you explain the basic theory of thermodynamics and how the extra juice that it would take to run an electric fan would cause more fuel consumption or more HP to run a metal fan.

How much HP does a couple of 500w lamps or a 1200w amp take away from your engine.

rimpainter.com

I would go electric if it is controlled by a thermo-switch. I agree, if the clutch on the stock fan is working right, it should not have much parasitic drag once under way. However, there is still a fairly heavy pulley adapter that is always spinning that will come off with the stock fan removal. That will free up a very tiny amount of parasitic drag at all times. You will also notice that you have more power off the line because the traditional engaged stock fan will no longer be roaring (engaged). And, if you time it right, you can switch off the electric fans (or they will on their own) and you will have zero drag off the line (electrical) in regards to the new fans.

For the price range you are looking at, I would do it. For the $200 I spent...I might have to think twice in the future.

It's all about timing. In other words, the elec fans are more precise under certain temperatures. It wont be all or nothing like the stock one. OK, done rambling. I say do it!

grams72

I would also say go for it
Whenever this subject comes up the first comment is that the stock or belt driven fans never fail.
Look at 90% of the new cars out there. They all use electric fans.

As for the power gains,
Its all about baby steps, remove dead weight and add HP.

rimpainter.com

Not to be antagonistic, but name a RWD that run's an electric fan as it's primary air cooling mechanism.

I am being serious. Not trying to start an argument by any means.

The only electric fan I have heard was on a Durango, and that was for the AC condensor.

Churnd

I think the only reason all RWD engines have belt driven fans is for reliability. The only reason most cars have electric fans is because they are front wheel drive, and the engine is turned sideways... so there's no way to run a belt driven fan.

I've had my Hayden fan for 2 some odd years, and never seen my truck overheat, even in 100+ degree weather.

However, I will admit that I might go back to a belt driven fan because I'm starting to get wary of how much longer that Hayden's gonna last. I'll probably pick up a brand new fan assembly one day when I get the dough.

grams72

Sorry I was refering to Cars not trucks,

I would agree that if the motor is sideways there is not a drive for the belt, but they still cool.

I do know that a lot of Hot Rod guys run electric fans to free up HP.

rimpainter.com

Agreed. I bet cost is a big factor too on production cars...

Churnd

I think the bigger the engine, the more of an improvement you'll see. Also, those guys probably have huge alternators which have no problem powering the fan.

It doesn't matter if you're talking about a car or a truck. Engines are engines regardless of what they're in. They all work the same way.

An electric fan will work fine supposing you wire it up correctly. Only thing is, it's probably a little more prone to failure... but if you can live with that, go for it. You will notice a slight increase in either HP or torque.

UKMyers

I put in a Flexi-Light fan that has the automatic thermostat. I hated listening to the clutch driven fan scream everytime I started the truck. I wouldn't recommend wiring one to come on all the time and wiring one that you could turn on and off is an overheat waiting to happen because eventually you'll forget about it. The only time mine ever comes on is when I'm wheeling slow or sitting in traffic. It never makes a sound when driveway at normal speeds. If wired properly the flexi one is reliable. I have had one overheat though when my ground decided to corrode up. As far as improvements I saw an increase in mileage as well as a little more pep in my engine. Check out www.summitracing.com for this fan. BTW it's not a very cheap mod.

Robinhood150

By my thermodynamics reference I was saying that you can't make energy from nothing, as a lot of people seem to believe when they switch to an electric fan.

I've already gone over the mechanical part of my assertion, so I'll concentrate on the electrical part now... First, I want to emphasize that switching to an electric fan to gain power and mileage is insignificant in the grand scheme of things. Therefore, this whole conversation is pretty much academic, especially when we're talking about nitpicky things such as energy losses in the belts and the viscous fan clutch.

First off, your question of:
"how the extra juice that it would take to run an electric fan would cause more fuel consumption or more HP to run a metal fan."
is misleading and taken out of context. I said, "Also, if it's ON ALL THE TIME, I'd bet you get less mileage than with the stock fan." Also, the stock fan is plastic, not metal. If the electric fan is on all the time then it's using electricity from the alternator all the time, whereas the stock fan clutch would disengage the fan when it's not needed.

1200 watts is equal to 1.6 HP.

So let's nitpick the energy losses of the mechanical system and the electrical system. The mechanical system will loose energy from the friction in the belts and friction in the viscous clutch (however, when hot the clutch locks up and has no energy loss). Contrast this to the electrical route...the engine's mechanical energy has be changed into electrical by the altenator, stored in the battery, then back into mechanical energy by the fan itself. Most electric motors are about 95% efficient and I'd guess the alternator is the same so that's a total of 10% loss of energy just in the conversions. I have no idea what the losses are to make the electricity travel through all the wires and battery. Let's guess 2%. So that's a 12% loss in energy just by going with electric. This is in contrast to the losses in the belt and belts aren't that inefficient.

Now, the aerodynamic side of things...Let's assume both fans put out the same CFM. If they put out the same CFM, then there's going to be about the same amount of drag on the fan blades and therefore the same amount of aerodynamic load on the engine. A couple notes here: 1. this is only when the fan clutch is fully engaged 2. sure some fan blades are more aerodynamically efficient, but lets face it, these aren't multimillion dollar turbine blades or something.

So that means the only place where there are losses is in the energy transfer, that is the belt Vs the electrical system. Which do you think are more inefficient, the belt or the alternator+battery/wires+electric fan motor?

You guys also mentioned hot rodders use electric fans...Are you guys drag racing your 2 ton SUVs from stop light to stop light? You can't compare the two because the vehicles are used for completely different things. Yes, the engine will spin up faster, but that does not translate into better efficiency. The hot rodders need the better engine response when 1/100 of a second means the difference between winning and loosing.

Also, a bigger engine will benifit less from an electric fan than a small engine. For example, which engine will feel the stock toyota fan more, a 5hp briggs and stratton or a 10,000hp diesel engine from a tug boat?

Robinhood150

Oh, and just to point out how much we're all nitpicking here and how trivial it is, the taurus fan on high uses 40 amps continuous. P=IV=40x12=480 Watts. That's only 0.6 HP. Assuming the aerodynamic drag of the mechanical fan and the electrical fan is the same, the mechanical fan will use about the same HP.

grams72

ah,
Thanks for clearing that up for me.