Electric Fans

[thewholefnshow]

I have search and 240sx.org's faq is down but I checked there too... So here's the deal, how many people have installed the electric fan, I would like to do it cause I hate that giant fan on the front of my car, and I would imagine the way that it is attatched must rob an HP or 2 at any rate.... Which fans are people using, and is the install difficult? Could someone maybe post a how-to so west could put it up in the FAQ's here?

[JpS]

well, if its electric then it wouldnt rob any hp b/c it would draw its power from the altenator(sp?)
unless you are running boost, or if you have the sr20, higher boost than stock, or you live in a hot part of the country, the stock fan should be fine

[silviasichigo]

Well from my experience, the FD3s fans take litte to no mods to hook up and that is what I have in addition to my stock belt driven fan. But you will feel a slight improvement in response if you remove you belt driven fan. The FD3S fans are probably the best fans you can get. That is if you can find them in a junk yard.

That is just my 3.675 YEN (= 2 cents) <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/tounge.gif" border="0" valign="absmiddle" alt=':p'>

[mrdirty]

OK, I'll get all technical here and hope it helps:

Firstly, you won't save any Hp by putting on an electric fan of the same mass if it's on most of the time. The entropic relations for any system (car or otherwise) state (in a nutshell) that since the alternator is not %100 efficient and the electric motor is not %100 efficient there must be some energy losses (heat) between the engine cranking the alt and the alt turning the el motor. In a direct drive, ie. fan right off of the engine, the only energy loss is mechanical friction which u would have with any fan anyway. Therefore it is MORE efficient to run a direct drive fan of similar weight (and moment of gyration).

However, if the new fan is much lighter, has a lower moment of gyration and is on only some of the time, then it might be advatageous to make the switch. Most of the time it's a show thing.

[v8killer]

Mr.Dirty-
You're gone. Really. Are you telling me that if you leave the stock clutch fan on the water pump that you're NOT encountering parasitic power-loss? Welp, I have ALL of my clutch fans off of my cars with aftermarket electric ones, and I have noticed on ALL of them that my throttle response was DEFINATELY faster, not to mention that I picked up a couple of ponies on my G-TechPro...
To all out there who know what they're talking about, go ahead, take the darn thing off- tell me it doesn't feel more powerful...

[thewholefnshow]

So you have done this a lot in the past v8killer? IS it easy? What's involved... I haven't found a lot on swapping fans, just a lot of ppl who said they have done it. Does it just bolt to the back of the rad mounts and then I have to find a power source and attatch a thermostat or is it more complicated than that?

[mrdirty]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (v8killer @ April 05 2002,07:43)</td></tr><tr><td id="QUOTE">Mr.Dirty-
You're gone. Really. Are you telling me that if you leave the stock clutch fan on the water pump that you're NOT encountering parasitic power-loss? Welp, I have ALL of my clutch fans off of my cars with aftermarket electric ones, and I have noticed on ALL of them that my throttle response was DEFINATELY faster, not to mention that I picked up a couple of ponies on my G-TechPro...
To all out there who know what they're talking about, go ahead, take the darn thing off- tell me it doesn't feel more powerful...</td></tr></table><span id='postcolor'>
Either u didn't read my post or u didn't understand it. I'm not going to bother re-posting it but if u can argue what i've said then go ahead. Parasitic losses are ANYTHING deriving power from an engine (yes even the alt) so instead of turning the blade you are now turning the alt which turns a motor which turns a blade...If however, u are going to a fan with a lower mass and lower mod of gyration then there will be a power gain (or reclamation). Now u will usually see an advantage because aftermarket fans are lighter and better designed, and do not have the clutch assembly. U would have gotten this from my last post if u actually read it.

BTW: If we're going to talk about who know what, try to dispute my earlier comments with something more intelligent than your last remark.

[sykikchimp]

just a note, the 240 comes with a clutch fan & electric fan. &nbsp;Thats why the temperature is always fairly solid on the 240. &nbsp;Even when your driving hard. &nbsp;Look under the fan shroud. &nbsp;You'll see it there. &nbsp;If you put the fans on and wire them to run of the relay that the current fan is on, then they will not run when not necessary. &nbsp;This of course will cause less perasitic loss because your not driving anything extra.

I've seen a couple guys not even add a fan. &nbsp;just remove the clutch fan, and run the stock electric one alone. &nbsp;This of course is a bad idea if you live somewhere where it gets real hot, and you drive in traffic with it.

[luey02]

newbie alert!!!! &nbsp;Ease off newbie, no one's picking on your too-deep-to-understand post. &nbsp;

From what I know about alternators, it does not become harder to turn just cuz it has to support another appliance. &nbsp;So fog lites rubs of hp too you're saying?! &nbsp;give me a break.. &nbsp;Alternater simply runs outta juice when there are too many loads it has to support. &nbsp;Then you get a higher amperage one. &nbsp;

seriously, all your big terms aren't goin to impress anyone here, maybe just yourself. &nbsp;It's better to make yourself more clear to understand than confusing. &nbsp;You want an example?? I bet ya.. &nbsp;Please explain moment of gyration, I doubt you fully understand the term to use it. &nbsp;and entropic state??? oh god, who're you tryin to fool.. &nbsp;

cockiness will get you no where on this forum, newbie! &nbsp;go to freshalloys.com...

[240meowth]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (sykikchimp @ April 05 2002,12:45)</td></tr><tr><td id="QUOTE">just a note, the 240 comes with a clutch fan & electric fan. Thats why the temperature is always fairly solid on the 240. Even when your driving hard. Look under the fan shroud. You'll see it there. If you put the fans on and wire them to run of the relay that the current fan is on, then they will not run when not necessary. This of course will cause less perasitic loss because your not driving anything extra.

I've seen a couple guys not even add a fan. just remove the clutch fan, and run the stock electric one alone. This of course is a bad idea if you live somewhere where it gets real hot, and you drive in traffic with it.</td></tr></table><span id='postcolor'>
no to say you are wrong...

but iirc the "other fan" is the A/C fan it came only on the 91+ models, correct me if i'm wrong

also, if you are installing electric fan(s), be causious the fan don't take a lot of power or else when you are bumping your subs in the trunk, your lights will dim as well =b

and the electric fan don't exactly run off the alternator... as in pulley wise, the alternator will still spin @ the same speed as it was before, w/ or w/o the fan, so the theory is correct, if you take the fan off, your engine will rev better and ultimately some little ponies that comes along w/ that, iirc a BMW M3 gains 8 ponies if it losses it's mechanical/clutch fan.

in a way, you can think of it as a lighter pulley, you took some weight off of the whole pulley set, thus, it's, sort of, like a lighter pulley

p.s. damn it, luey beat me to it... well, ease up on the newbies, and if they want to go else where, go 240sx.or not FA &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/wink.gif" border="0" valign="absmiddle" alt=';)'>

[sykikchimp]

I don't think that was called for at all luey. &nbsp;Do you yourself understand those things? &nbsp;who are you to call him out when you don't understand it either. &nbsp;Simply ask him to be more specific. &nbsp;Don't go off on him. &nbsp;He is trying to be helpful. &nbsp;give him a chance. &nbsp;You yourself are still a somewhat of a newbie too.

He may have a valid point, and I'd like to hear more specifics about it. &nbsp;Can you please elaborate MrDirty?


240meowth - your probably right. &nbsp;I forgot about the setup on the 89-90 models. &nbsp;Not sure about them though.

Also I'm pretty sure more current being drawn from the alternator does create more drag within the alternator, thus creating more drag on the crank. &nbsp;And yes, your fog lights could be drawing away from your hp too.

[240meowth]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (sykikchimp @ April 05 2002,1:29)</td></tr><tr><td id="QUOTE">I don't think that was called for at all luey. Do you yourself understand those things? who are you to call him out when you don't understand it either. Simply ask him to be more specific. Don't go off on him. He is trying to be helpful. give him a chance. You yourself are still a somewhat of a newbie too.

He may have a valid point, and I'd like to hear more specifics about it. Can you please elaborate MrDirty?


240meowth - your probably right. I forgot about the setup on the 89-90 models. Not sure about them though.

Also I'm pretty sure more current being drawn from the alternator does create more drag within the alternator, thus creating more drag on the crank. And yes, your fog lights could be drawing away from your hp too.</td></tr></table><span id='postcolor'>
eaise it up on luey, chimp, he's got 2 starts &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/biggrin.gif" border="0" valign="absmiddle" alt=':D'>

i recall alternator spins n generates electrocity, but i don't think the lack of electrocity will cause it to spin slower...

if so, that means my 588watt (in all) system must of killed me... &nbsp;and maybe i should lose the fog lights... &nbsp;and turn of all my lights to increase fuel efficentcy?

correct me if i'm wrong, i'm just realy confused...

[v8killer]

Mr. Dirty-
It wasn't intended to be insulting, that's just how I talk. Parasitic losses from the clutch fan can't be compared to the losses from the alternator anyways! The alternator doesn't have to work any harder for it to power electric fans?!? The alternator spins exactly the same, no matter clutch fan or no. I know you can't remove the alternator on a street car, but the losses are much greater with the fan spinning. You also have to keep the loss from the pulley on the fan, as the water pump is attached to it, but at least the blades aren't trying to spin through the air...

[mrdirty]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (luey02 @ April 05 2002,2:50)</td></tr><tr><td id="QUOTE">newbie alert!!!! Ease off newbie, no one's picking on your too-deep-to-understand post.

From what I know about alternators, it does not become harder to turn just cuz it has to support another appliance. So fog lites rubs of hp too you're saying?! give me a break.. Alternater simply runs outta juice when there are too many loads it has to support. Then you get a higher amperage one.

seriously, all your big terms aren't goin to impress anyone here, maybe just yourself. It's better to make yourself more clear to understand than confusing. You want an example?? I bet ya.. Please explain moment of gyration, I doubt you fully understand the term to use it. and entropic state??? oh god, who're you tryin to fool..

cockiness will get you no where on this forum, newbie! go to freshalloys.com...</td></tr></table><span id='postcolor'>
I hope that I didn't make u feel too stupid Luey. Yeah, i'm a *newbie* here (or whatever u want to call it, who gives a sh*t), but &nbsp;I am an engineer (mechanical) and thought I'd try to help this guy, some of us have to work for a living and don't have time to sit on the computer all day.

1) There is something called the conservation of energy,
&nbsp; &nbsp;where do u think the energy from the alt comes from? Yeah, the engine. That's why high amp alt's are a bigger drain on the engine. The electrical charge doesn't just appear.

2)Moment of Gyration : Is mass * radius of gyration. Go look up radius of gyration, I'm not here to give u a kinematics lesson. Look up mass while your at it too. And that little symbol mean "times", maybe u haven't covered that yet.

I don't really care if u are "impressed" or not, I'm not about to dumb my responses down so that the un-educated neanderthals like you can feel smart, but I will try and help anyone who asks; and if u don't like it then....well....who cares?

So thanks for sharing, and chimp, I'll post seperately some clarification.

[240meowth]

hey, eaise it up in here man, we really don't need all the name calling. Let's just all be friends...

ahh, feeling like a modreator <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'>

btw, i still think the alternator will still spin @ the same speed w/ the engine, and i won't be harder to spin. because the alternator gives out a certain amount of energy all the time dosn't it? just that most of the time, not all the energy from the alternator is used.

well, if the alternator is more difficult to spin w/ more electronical equimpment, than... anybody want my 400w blaupunkt amp and my 2 boxed 12" Jensen speakers? it's weighing my car down anyways... and i never go down the street bumping music... it's just sittin there hittin the soft bass... what a waste... &nbsp;i'm thinking 300 bucks out the door for these, e-mail me if interested [email protected], BUT ONLY IF the alternator is harder to spin due to more electrical equiptmen...

i'm waiting for mrdirty's response &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'>

[mrdirty]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (sykikchimp @ April 05 2002,3:29)</td></tr><tr><td id="QUOTE">I don't think that was called for at all luey. Do you yourself understand those things? who are you to call him out when you don't understand it either. Simply ask him to be more specific. Don't go off on him. He is trying to be helpful. give him a chance. You yourself are still a somewhat of a newbie too.

He may have a valid point, and I'd like to hear more specifics about it. Can you please elaborate MrDirty?


240meowth - your probably right. I forgot about the setup on the 89-90 models. Not sure about them though.

Also I'm pretty sure more current being drawn from the alternator does create more drag within the alternator, thus creating more drag on the crank. And yes, your fog lights could be drawing away from your hp too.</td></tr></table><span id='postcolor'>
Yep, that's right. The more current u push, the harder the armature has to be pushed thru the magnetic field. So everything u power off of the alt takes energy away from the engine, this is a principle of any generator.

Alternators are around %70 efficient, as are most electric motors. So by the time the juice gets to the electric fan the efficiency drops to ~%50. So 1/2 the energy is wasted. If u have the exact same fan on 1/2" the time you will see no change. If the fan is lighter and has a tighter radius of gyration u will see an energy savings. This is the case most of the time. If u could lighten the existing fan and clutch ass'y then you'd have the best of both worlds.

[HotRodGuy]

All I know is that I've removed the mechanical clutch fan from the past 4 vehicles that I've had (or still have) and there was a noticeable improvement. More actual hp or not I don't know, but I could "feel" the difference.

Any mod that I can make that makes the car "feel" faster has to be good.

Right now I'm just using the factory aux electric fan. I checked the wiring diagram in the manual and found out that it is connected to 2 relay's. One to the AC and the other to a theromostat switch. So far it's doin' good, but It ain't been too hot outside yet. I fugure that if it git's too hot in the summer then I'll install another electric fan.

Oh yeah, btw I live in the cuntry and don't drive in stop and go traffic much so that probably makes a difference.

[weitau]

mrDirty has a point. let me try to explain in layman's terms (don't flame me for using that word, please) what he was trying to say.

The Situation: You have to run a fan, either the clutch fan or electric.

If the clutch fan is not spinning, but the electric fan is, what energy saved by not running the clutch fan is used to propel the alternator & electric fan. Therefore by removing the clutch fan, you do not gain any horsepower. (conservation of energy)

What mrDirty did not consider is that when the engine revs to higher RPM's, the clutch fan causes additional drag on the engine both in terms of inertia of the fan itself, and also in moving more volumes of air. (Force=Mass*Accelleration)

In contrast, the electric fan spins at the same speed, at any engine RPM. So when you accellerate, the electric fan does not add additional load as opposed to a clutch fan.

The alternator is going to spin faster regardless if you have a clutch or electronic fan, and since the electric fan is running at a constant speed, there is no additional energy consumed by the alternator during accelleration.

Sure, the electric fan is consuming energy that would have been used by the clutch fan, but the electric fan is drawing energy from the battery. And since the battery is constantly being charged until it reaches its capacity, the load placed by the battery on the alternator does NOT increase during accelleration.

How about that explaination?

Now can someone tell me how I can hook up a good, light weight electric fan that turns on via thermostat?

[240meowth]

so does that mean my 588w stereo system is robbing my HP's &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/sad.gif" border="0" valign="absmiddle" alt=':('>

FOR SALE
300 bucks
2 12" jensen subs
2 boxes
1 blaupunkt 400w amp
e-mail me =)

[nrcooled]

To be perfectly honest with you I found that the electric fan works wonders and have felt "seat of the pants" power gains I ditched the pulley fan and the electric fan for an aftermarket piece of kit. &nbsp;But I also have an SR with no AC so it wasn't a big decsion(sp) and I rigged up a toggle switch in the cabin so I can turn it on and off when I feel like it and also leave it on to cool the turbo after I have cut the engine off. &nbsp;The install was super simple and took all of an hour and that includes trips to radio shack to get the stuff that I needed to rig up the toggle switch. &nbsp;Definately not a job to scared of. &nbsp;Run a ground to the chasis(sp) and hot to a fuse (a 12v or 15v) on the fuse panel in the cockpit some where between the fan and the fuse put a 20v fuse for any shorts and hook up the toggle switch anywhere between the fan and fuse.
fan $100 (20v fuse should come with fan)
20ft 14 gauge wire $7
toggle switch $2

Hope this helps just holla if you need more detailed info this was just a short rundown. <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/biggrin.gif" border="0" valign="absmiddle" alt=':D'>

[Grant]

Well, clutch fan relieves rotating mass, and does help the car a bit. Right now my A/C fan is wired to go on as soon as the car is started, and stays on. This is sufficient for N/A KA motors. I was told unless you go with a turbo setup, you wont need a different fan.

Anyways, I believe if you too big or too powerful of a fan on the car, it will draw more current,which results in drawing more current from the motor, which results in drawing power for the engine. It is just like having air conditioning.


A good solution may be just a lightweight flex fan (mechanical).
Or stick with the stock a/c fan or an aftermarket one that doesnt draw too much current, but functions better.

[mrdirty]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (weitau @ April 06 2002,02:12)</td></tr><tr><td id="QUOTE">What mrDirty did not consider is that when the engine revs to higher RPM's, the clutch fan causes additional drag on the engine both in terms of inertia of the fan itself, and also in moving more volumes of air. (Force=Mass*Accelleration)
...</td></tr></table><span id='postcolor'>
That's a good point, looking at it that way there would be a noticable difference with a el fan @ higher rmp.

[weitau]

Thanks mrDirty! &nbsp;but I am glad that you introduced a more scientific approach!

[DuffMan]

Mrdirty is correct, any load on the alt is going to rob you of power. Yes your headlights, stereo ect take away power when they're on. The higher current the alt makes, the greater the electromagnetic resistance on it to turn.


What do you think electrical power comes out of some mysterious magical force? Geeze what is this the 15th century?

Try driving a really dog ass slow car some time where you can actually feel the power loss when you turn on the headlights. &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/tounge.gif" border="0" valign="absmiddle" alt=':p'>

EDIT: One more thing. The clutch fan, i believe, will spin faster when the engine spins faster. This is where the main advantage of an electical fan comes in. The fan is there to cool the engine at idle. Spinning that fan ten times as fast when you are racing is going to require that much more power from the engine. With an electical fan, this is constant. HotRodGuy is right that you can feel a difference. It may even be fairly significant at high RPM.

[HotRodGuy]

Thanks fer agreeing with me DuffMan! <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/biggrin.gif" border="0" valign="absmiddle" alt=':D'> &nbsp;

And thanks to everyone else for the scientific and layman's explanation's of this topic!

[bing]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (240meowth @ April 05 2002,06:18)</td></tr><tr><td id="QUOTE">so does that mean my 588w stereo system is robbing my HP's <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/sad.gif" border="0" valign="absmiddle" alt=':('>

FOR SALE
300 bucks
2 12" jensen subs
2 boxes
1 blaupunkt 400w amp
e-mail me =)</td></tr></table><span id='postcolor'>
you spent $300 on Jensen???

heheh j/k

my buddy with a 300z always swaps for an electric fan,

[240meowth]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (bing @ April 06 2002,10:00)</td></tr><tr><td id="QUOTE"></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (240meowth @ April 05 2002,06:18)</td></tr><tr><td id="QUOTE">so does that mean my 588w stereo system is robbing my HP's <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/sad.gif" border="0" valign="absmiddle" alt=':('>

FOR SALE
300 bucks
2 12" jensen subs
2 boxes
1 blaupunkt 400w amp
e-mail me =)</td></tr></table><span id='postcolor'>
you spent $300 on Jensen???

heheh j/k

my buddy with a 300z always swaps for an electric fan,</td></tr></table><span id='postcolor'>
there's amp n boxes as well... &nbsp;i'll even throw in my wires for free!

my question is, how much hp lost are we talking about here? for example, my 588w stereo, if i turn it to full blast, w/ my head light and fog light on and interior light, while charing my cell phone (?w) in a rainy day w/ my wipers and heat on full blast. &nbsp;and the rear defrost on, while breaking. &nbsp;will i lose like 10 hp?

[Jeff240sx]

Heres my theory on this. &nbsp;It's a theory. &nbsp;*Flame Shield*
If you have an alternator, rated at 70 amps, isn't that 70 amps max power? &nbsp;So if its max power, it would achieve that max power based on the maximum speed of the amps pulley. &nbsp;Which would be redline, right?
Next thing to establish. &nbsp;All things electrical are run off the battery. &nbsp;I don't hook my amp wire to the alternator, nor do I hook it to my distributor. &nbsp;To the battery. &nbsp;And if I had an electric fan, I'd hook that to the battery, too!
All these things drain power off the battery, not the alternator in any way. &nbsp;And I would assume ( I know what happens when you assume! ) that the alternator's charging power increases linearly with the revs of the pulley.
So. &nbsp;To put my theories together...
The alternator is making power depending on what rpms the pulley is spinning at, recharging the battery. &nbsp;When stuff is on, it drains off the battery. &nbsp;When you attach an electric fan to the battery, your not putting a 10 pound weight on the blade of the alt pulley, so you're not hampering its performance. &nbsp;So it does its job, and creates power in a linear scale, not a needed or not basis.
Someone correct me if I'm wrong.
-Jeff

[240meowth]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (Jeff240sx @ April 07 2002,12:20)</td></tr><tr><td id="QUOTE">Heres my theory on this. It's a theory. *Flame Shield*
If you have an alternator, rated at 70 amps, isn't that 70 amps max power? So if its max power, it would achieve that max power based on the maximum speed of the amps pulley. Which would be redline, right?
Next thing to establish. All things electrical are run off the battery. I don't hook my amp wire to the alternator, nor do I hook it to my distributor. To the battery. And if I had an electric fan, I'd hook that to the battery, too!
All these things drain power off the battery, not the alternator in any way. And I would assume ( I know what happens when you assume! ) that the alternator's charging power increases linearly with the revs of the pulley.
So. To put my theories together...
The alternator is making power depending on what rpms the pulley is spinning at, recharging the battery. When stuff is on, it drains off the battery. When you attach an electric fan to the battery, your not putting a 10 pound weight on the blade of the alt pulley, so you're not hampering its performance. So it does its job, and creates power in a linear scale, not a needed or not basis.
Someone correct me if I'm wrong.
-Jeff</td></tr></table><span id='postcolor'>
that's what i thought, the alternator spins and generating current all the time, and there is usually an excess of energy, thus used to charge the batter... &nbsp;maybe i'm lost...

[9591]

Lemme try to clear some things up, here (the most "important" part is in point #3, for those not inclined to read 'em all):

1) The alternator and battery are wired in parallel, which basically means that everything electrical is running off *both* of them at the same time (when the engine is running, and both are working properly). Essentially this can be considered as running only off the alt, as any relief that the batt gives to the alt, has to be made up by the alt in order to recharge the batt.

2) The alt only supplies as much current as is required by the devices it powers. The devices "suck" the current they need, the alt doesn't just pump out a certain amount all the time. For example, say you somehow had two alternators on your engine. Both are rated at 100 amps, but one is only wired into your super-cool 14 watt thingamajig, while the other one is hooked up to the main system, which keeps your battery charged, your car running, and everything else. The alt powering the thingamajig is only going to "put out" about 1 amp, even though it's a "100 amp alt", no matter how fast it's turning, because that's all the thingamajig draws (needs).

3) As more current is drawn *from* an alternator, more current will flow *through* it. More current through the alt windings will create a stronger magnetic field around them, which will more forcefully oppose the rotation of the alt. Therefore, a higher current drain (load) on the alternator will increase the power required to keep it turning. That's not theory, that's fact.

4) 1 HP = 746 watts. A 100% efficient alt would therefore need 1 HP to drive 746 watts worth of electrical devices. No alt is 100% efficient, of course, so they'll actually need more HP. I really have no clue what a good estimate is for efficiency, but I seriously doubt that the alt will ever come anywhere close to needing 10 HP. Maybe 2 or 3 in extreme cases.

My "explanational skills" were probably lacking in the above, but maybe something got through.

[240meowth]

thanx man, i got all whackely confused...

[9591]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (240meowth @ April 07 2002,06:31)</td></tr><tr><td id="QUOTE">thanx man, i got all whackely confused...</td></tr></table><span id='postcolor'>
I aims to please &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/wink.gif" border="0" valign="absmiddle" alt=';)'>

I was just saying that, yes, a high power amp *does* suck HP from your engine, but not much.

I also didn't mention that an electric fan, while still sucking HP, likely sucks less than a mechanical one, due mainly (IMO) to it's lower mass and, possibly (IMO), the higher efficiency of the way it's driven.

[geeaj]

89-90 do have factory electric fans. They are mounted on the front of the radiator.

[gschroeder78]

Correct me if I'm wrong but doesn't the mechanical fan pull cool air through the radiator to cool the engine?
The electric fan on the front of the radiator couldn't do the same thing because the air wouldn't get to the engine. An electric fan would need to be mounted on the inside to have the same effect. &nbsp;I'm under the understanding that the little elec fan is the ac fan, But I could be way off.

[Jeff240sx]

Yeah, the electric fan is the A/C fan. &nbsp;But, what most people are talking about, is swapping the mechanical fan for the electric fan. &nbsp;This would put the electrical fan in the same place the mechanical fan used to be.
-Jeff

[Jeff240sx]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (9591 @ April 07 2002,08:13)</td></tr><tr><td id="QUOTE">4) 1 HP = 746 watts. A 100% efficient alt would therefore need 1 HP to drive 746 watts worth of electrical devices. No alt is 100% efficient, of course, so they'll actually need more HP.</td></tr></table><span id='postcolor'>
Someone here said an alternator is 70% efficient, which most stuff is 70% efficient (I know I am <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'> )
So I'm gonna use that number...
At 70% efficiency, the alternator will use 1hp for 522.2 watts?
Does that mean the my system alone is using 1.1hp? &nbsp;Then my lights, headunit, defrost, ect, are gonna rob more horsepower?
-Jeff

[HotRodGuy]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (Jeff240sx @ April 07 2002,2:27)</td></tr><tr><td id="QUOTE">Yeah, the electric fan is the A/C fan. But, what most people are talking about, is swapping the mechanical fan for the electric fan. This would put the electrical fan in the same place the mechanical fan used to be.
-Jeff</td></tr></table><span id='postcolor'>
Yes, the little (factory) fan on the radiator is an A/C fan, but it's also connected to a theromostat switch (checked it with the wiring diagran in the FSM) that turns it on when the engine reaches a certian temp. (don't know what that temp is, but mine hasn't overheated yet)

And when you install an electric fan it dosen't go in the same place as the mechanical fan...it can't because the mechanical fan mounts to the water pump. If you do install an electric fan you need to put it as close to the radiator as possible, like where the factory A/C (aux) cooling fan is located.

And yes, you can mount an electric fan on the front of the radiator. It has to be a "pusher" fan (pushing the air thru the radiator) not a "puller" fan (pulling the air thru the radiator).

So, when ppl talk about swapping the fan their actually talking about removing the mechanical fan totaly and installing an electric fan on the radiator.

Just thought that I'd clear thangs up a bit. <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'>

[9591]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (Jeff240sx @ April 07 2002,2:31)</td></tr><tr><td id="QUOTE">Does that mean the my system alone is using 1.1hp? Then my lights, headunit, defrost, ect, are gonna rob more horsepower?
-Jeff</td></tr></table><span id='postcolor'>
Sounds good to me. Two more things to keep in mind, though:

Is that 588 watts the output power of your amp, or the input power? If it's output power, then it will actually draw considerably more from the alternator (efficiency issue, again).

The amp is only going to be drawing all that power when it's pumping at maximum volume. The rest of the time it'll be drawing less.

[silviasichigo]

http://community.webshots.com/storage/1/v4/0/2/13/349oo2130PGqgs_th.jpg

Well I said before also you can go with the RX-7 FD3S electric fans They are the same dimensions and they are probably the best fan you can buy especially if you get them out of a junk yard. <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/biggrin.gif" border="0" valign="absmiddle" alt=':D'>

[flipboi13]

I'm just going to replace the electric fan with an aftermarket piece, or maybe go look for that RX7 fan and use a flexfan to replace that ugly (and slow) plastic one. Just my opinion...