I know this has been ran in the ground about the electric fan deal. I have been reading about this mod for quite some time but have always put it off. Well I finally did it and Wow, I did not know there would be that big of a difference. I haven't used the G-tech yet but the pants-O-meter tells me so. She revs quickly and smoother, maybe it's all in my head but my exhaust note sounds better. But I thought I would let everyone know this is a must have mod.

 

Congrats, but what electric fan did you buy? Also, can you post some pics?

 

You're probably hearing the exhaust better now that you don't have as much engine noise.

Have you se the thread about the heat and the loss of power in the heat? I'm thinking somehitng isn't right. Worse case you flip on the fan manually.

So yes, what he said. What fan, etc. etc.?

 

Call me crazy, but I hardly ever run the A/C. Even though it gets near 100 F, my A/C is the set of windows. I don't even think my fan comes on. It may whirr real loud if I've been sitting at a stop light for more than a minute, but it only stays on for about 10ft after the light turns green (I guess that says, the engine actually does get very hot in city stop and go traffic). Unless I don't know what I'm talking about, is it ok to say an electric fan won't give me any more horsepower? Living in Texas, I have been wanting one for a very long time, hoping it would change things. So, I guess I'm out of luck until I start running the A/C. But then I'll be back to square one since the A/C takes about 12% of the horsepower (I swear I read that stat in an engr phys book). Any other theories to keep the engine cool?

-Joel

 

I just did my fan last week also. I see the same thing you do, engine revs quicker and higher before shifts at WOT. I also noticed that my slight rough idle left with the clutch fan. I did pick up some vibration from the electric fans though. I think some weather striping between the stock shroud and the radiator will help cure that.

I used a fan assembly from a camaro. This thing will suck the butt out of a cat. It's way more fan than the truck needs. I just liked the unit because of the rubber flappers it has to let extra air pass through at highway speeds. I did twin fans on my Bronco and sitting at idle, temp never budged. At highway speeds, the fans wouldn't allow enough air through the shroud and the truck would get hot. I didn't want that to happen this time.

RED BULL,

Even though you don't really hear your clutch fan much, the engine is still spinning that 15 lbs. It's hard to believe the difference getting rid of that thing makes until to see for yourself.

 

As soon as I hit the send button, I thought to myself: Electric Fan! As soon as it gets to some preferred temp, it will kick on electrically and not suck any HP from the engine.

I left the previous reply because it had a couple other 'what if's' in there.

Also, I'm kind of confused how a fan would create hp loss. Sure, it may swirl some of that hot air around in the engine compartment. But, once the fan has been on for a couple of minutes, won't most of that hot air be blown out from under the engine? It's the general theory of conservation of mass. You have a designated volume currently filled with whatever (for our purposes, it's hot air). The fan sucks cool air from outside and forces it into our perfect volume under the hood. The hot air already inside the engine compartment has to go somewhere... away from the engine compartment as far as we're concerned. And eventually (about two minutes or so), all of the hot air has been replaced with cool air (except for the extra that is being created by the engine). Except, now, we've got a whole lot more cool air surrounding the engine. It's no problem whatsoever for the cool air to displace the hot air from the engine to somewhere else (hopefully out from underneath the engine compartment). Plus, we've always got a constant amount of cool air entering our engine compartment as long as the fan is still on.

Just a thought about that.

-Joel

 

I think that you get alittle loss from the alternator running to supply the power to the electric fan. Conservation of energy.

 

I will try and have some pics up tonite, also will have more info then. I'm at work right now and can't stay long.

 

Electric fans do not operated with free energy. That energy must come from somewhere. That energy comes from the battery and the charging system.

The alternator sucks a lot more power from an engine than most people think. I don't have any specific figures, but in my youth, I fooled around with a 35 amp alternator. I hooked it up to a 1 horsepower electric motor and connected the alternator to an old battery. The end result was the 1 hp motor was strained and quickly overheated. There went my idea of building a free battery charger.

The reason you are feeling better acceleration is the fact that the mechanical fan is never fully disengaged. At best, it's slipping, not free-wheeling. Park your truck and open the hood. Start the engine. Feel the air blowing? It takes energy from the engine to move that air. Have somebody step on the gas. The airflow increases. This increased airflow means more energy is being used. The mechanical clutch fan will always eat up some energy and when engaged, it will eat up a whole lot more.

However, after saying all of that, I'd have to say that for a given amount of air, a mechanically operated fan makes more efficient use of energy than an electrically operated fan powered by that same engine. Why? Generating electricity is not 100% efficient. There is a lot of energy loss when our alternators generate electricity.

 

Dennis,
Yes, the alternator has to work harder when the electric fan is turned on. The advantage is that the fan is only on when you are stuck in traffic or driving at slow speed in hot weather, which is probably less than 5% of the time for most of us.

Even when it is on, IMO the electric fan will require less power than your stock fan. The electric fans are usually much lighter and there is no clutch assemlby and mounting bolts to spin.

Take your 1 hp motor and see how fast it will spin a stock fan - not very fast. After pulling my stock fan off and spinning it in my hands, it is very beleivable to me that it would take 10+ hp to spin that thing at 5,000 rpm.

That being said, I could feel no pronouncedl difference in power from my electric fan (there must be some gained), but there has been a nice increase in fuel mileage of at least 0.5 mpg.

 

 

You sure about that? I just can't see them doing it on a truck that's setup for 4 wheeling and/or towing heavy loads.

I guess I'll just have to keep my truck until the Ford engineers get some sense back.

I really hate to even think about what an electric fan that has enough capacity to keep my truck's engine cool with the a/c on while towing 6,000 lbs uphill at 35 mph with a 35 mph wind at my back would sound like.

 

dirt bike dave,

I don't doubt that it took some effort to spin your stock fan, but what you were feeling is the mass. It takes a lot of effort to get that much mass turning, but once it's turning, it takes very little energy to keep it spinning. Think about gyroscopes. Of course in this case, there is a fan attached and this causes drag, but I doubt that you would feel much of it when you spin the stock fan by hand. Like any other fan, the faster you spin it, the more power it will require. The slower it spins, the blades will have less of an effect.

Pose this problem to an engineer who knows this kind of stuff. Assuming you have an engine and have a fan directly driven by the engine blowing a certain cfm of air. Now hook that fan up to an electric motor that gets it's electricity from an alternator and battery hooked up to the engine. Ask the engineer which setup operates more efficiently for the same cfm.

It's the same reason why you don't run a pump that requires 8 hp with an electric motor hooked up to an 8 hp generator. It will probably take something more like a generator with a 30 hp engine to produce the power required by that 8 hp pump. It would be a lot more efficient to run that pump with a 10 horsepower engine directly.

You lose a lot of energy when you generate electricity and the farther it has to travel, you lose that much more efficiency. That's the nature of electical generation.

In automotive installations, the electric fan ends up being more efficient over all because it doesn't run all the time and above certain speeds, it may not run at all, whereas the stock fan is always running and always sucking up varying amounts of energy.

Got a question. If you have an a/c and it's running. the fan is supposed to be on when the a/c compressor is on. Does the fan shut off with the a/c on and you're driving at 55 mph or does it stay on all the time until you shut off the a/c? As I recall the cars I had that came with electric fans, the fans ran constantly with the a/c on no matter what the speed was. No wonder I had alternators and batteries fail so often on those cars. I had the a/c on all the time.

 

Next time I have to take my wife's mini van in to the dealer for a repair, I'll ask the service writer to hang on to the front end while the hood is up. Then I'll drive down the freeway at 65 with the AC on. I'll let ya know what he says.

 

I've got a question and a few statements that many could respond to:
1) What about on some fall day removing the fan all together and doing a short term driving test? Since the fan is generally only needed 5% of the time could someone get away with that under the right situations.

2) I noticed on my wifes Maxima the electric fan does not come on until the water temperature is up. Even sitting still. I did notice however that the cooling capacity of the A/C seems to be less until the fan is activated while sitting still. The same was true on my '89 Probe GT.

3) Is there a difference in compressor cycle time between A/C and Max A/C on the selector switch or does it only increase the circulation fan speed? (I have had this question for some time)

I'd like to do the fan removal test just to play around a bit. I would really like the electric fan but have a wife who believes that time spent beyond filling the gas tank is to much time playing with cars. Anyway, I just thought I'd through those out and see what is said