Can also read the thread below in my sig about the E-fan and clutch fan.

Your correct in knowing that the e-fan does not claim as much HP as the clutch. The clutch has a greater chance of claiming more HP then the e-fan but nothing you may be able to feel.

In the e-fan link in my sig, click on the link about the S4 Fan Estimation, that gives you good info about the clutch fan.

To get a closer approximation, you want to do the math using 13v and not 12v. Not a large difference though.

Also, the clutch fan does not take anything over 5hp. It would take less then 2 most of the time but usually in the decimal range.

I thought the E-Fan conversion was to make more room in the engine bay... :confused:

Thats why I would eventually like to do it... :pat:

What are you making room for? Most of the people who say they swapped to e-fan "to make more room" don't actually use any of the space they've freed up.

Your right but its easier to work on the engine without that large shround in the way.

+1

I dont have an overly modded car but like any other 7 it needs to be worked on regularly... Its nice to clear as much crap out of the way as possible... Plus it just looks nicer... :D

Yes. But the same holds true for the stock fan as well. It freewheels when not in use.

Being that the weight is very close to the center of the shaft, and the freewheeling nature of the clutch fan, I don't know if it would make that much difference. Certainly when I installed my e-fan (because my clutch fan died....) I couldn't tell that I had switched (well, save for the fact that my alternator now struggled to keep up).

Are there over drive pulleys one could install?

Actually this is incorrect. Although you may have just worded your phrase wrong compaired to what you actually ment. The amp draw for a fan is most of the time about 10amps, a lot of times near 15+. Im guessing you were talking about the HP consumption of the e-fan due to the amp draw compaired to the clutch fan, in which case, you are correct.

While the fan is running, you would have the extra drag from the alternator. Still would be minimal. While the e-fan is off though, you have lost nothing and have free'd up any little hp that was taken by the previous clutch fan, as well as the current e-fan.

I have never seen any but im sure you could get some made. Doing this though could over spin the alternator or water pump, depending on what you "overdrive". Personally, I would like to overdrive the alternator slightly, havn't done the math to figure out how much I could go but at idle, it seems to spin to slow to charge much.

That's what i'm thinking, however I believe you can swap out the diodes to get a similiar affect, however I think the output would still be rather low at idle.

an Overdrive pulley would be smaller than the shaft pulley(?), but i'd imagine it would only need a few mm to a cm in difference to get the desired affect.

What i'm curious about though is why anyone would want HP at idle? since both the efan and clutch fan usually only spin at low speeds or at idle. There's rumors of better throttle response from an efan and most who have done the conversion agree. Besides that and space it makes no real difference in the amount of usable HP. As for my reasons for conversion the fan and shroud were broken and I'm also planning on doing a N/A->turbo conversion (so with that space I can run intercooler piping).

Right, if you notice the alt pulley is already smaller then the main pully but in some situations doesn't seem small enough. They are that size for a reason though, If you do a lot of high rpm racing around then I would stay away from overdriving the alt even more.

Its not getting HP at idle, its trying to free up and HP through the poewr band that the clutch fan is said to consume. As I state before, its usually in the decimal range but can take as much as 2+ hp.

I can't remember if switching to an e-fan increased my throttle responce or not while the fan was off or on. Its been about 5 years. I can see how it would, but I don't think its anything to jump up and down over either.

yeah, that's what I was thinking--but (correct me if i'm wrong) the stock electrical system already struggles to keep up with demands. As previously stated it's only going to produce the amount of amps that is drawn from it. I think a better way to go might be to replace the diodes in the alt to produce more amps at all rpm range, but that would require finding an upgrade kit and what not. It just seems that some people swap over to an FD alt to fix their power consumption problems, but i'd imagine it all depends on what's consuming your power, I doubt an efan would consume enough by itself to warrent an upgrade, but combine it with an aftermarkte stereo system it might.

I see what you're saying now, but it seems a little asinine to me. But that's just my opinion.
My sentiments exactly.

The conversation is past this, but I'll add these two sentences anyway:

• The clutch fan taps the engine's mechanical power directly, while the electric fan converts to electrical power at the alternator, then back to mechanical power at the fan, and each conversion is less than 100% efficient.
• Reasonable electric fans have an upper-limit of airflow, while the stock fan has a much higher limit.

Those don't tell the whole story, but they're interesting to keep in mind!

I still think this is more in people's heads than anything else, because it makes such a difference visually. There's not that much "on the engine" that's blocked by the shroud. I've worked on pretty much every part of my engine at some time or another, and only needed to remove the shroud once to remove the water pump. I'm doing something in the engine bay often and if it actually got in my way on a regular basis I'd be much more interested in removing it. What regular tasks would actually be made easier?

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

I guess on the other hand... Since I have removed the stock intake, the shroud does work great as a place to set tools while I work on it...

would you gain any throttle response by getting an e-fan?

the only reason i'd get an e-fan is cause i would like to install a reverse vented hood, which WOULD help reduce engine bay temps.

Listen, I work at Advance Auto and test a lot of alternators. When you put a load on an alternator, it puts an electrical resistance on the shaft, and makes it harder to spin. If this wasn't true - then an alternator would produce max output at idle or at WOT - which is also a known fact that it doesnt.

The alternator does not increase amps based on RPM solely.

Any Mechanic will verify what I have said to be true. I am a mechanic myself. Maybe you should research your stuff before you make ignorant claims...

-Chris

Ohhh lord, a mechanic working at AAP :wallbash:

How about kicking my 90 amp sound sytem at full blast while the car is at idle; will the alt put out its "100" amps?


Yeah, didn't think so :sadwavey: :rlaugh:

So in conclusion, an alt will not put its max amp output at idle, irrelevant of load...

There is something you can do with an EFan that you can't do with a clutch fan. Switch it OFF before a run on the drag strip. That and controlling the exact on and off temps, and having it kick on and run after the car is shut down too cool things off.

But I would gladly go back to the clutch fan any day if I could. On my current setup it would spin backwards.

oh hey look! a battery! it can STORE and RELEASE electrical energy? no shit!

We are not talking about batteries :dunno:

On any case, where is that energy coming from?

And if the demand is MUCH HIGHER than the supply?

The battery is part of the equation if adding electrical draw to the system, be it an e-fan, or high-power stereo system, or auxiliary lighting, cause the load to exceed the alternator's output at idle or low speeds. As has already been noted, the FC charging system struggles to keep up with demand at idle - for example, idling with my headlights on, if I use the power windows, the idle sags, due to the extra load on the alternator, and lights dim. Same if my foot is on the brake, lighting the brake lights.

Under such conditions, where the alternator is not supplying sufficient amps for the electrical draw on the system, the battery "chips in" from it's stored energy. Two problems follow from this - one is, that cannot go on indefinitely, as the battery will eventually run flat and voltage/amps supplied to electrical system will drop below that needed to keep the car running - although in practical terms, that would take a lot of time idling - possibly hours, depending on how much the battery has to "make up". Secondly, if extra load on the electrical system from an e-fan, for example, causes the car to draw on the battery while idling or at low speeds, the alternator will work harder once engine speeds increase to recharge the battery again, meaning it is possible that the extra load of the e-fan effectively remains on the engine, via the alternator and battery, after the fan may no longer be running - effectively, a deferred load.
I just read Mr. Cake's writeup on "the efan myth" - he's pretty much nailed it - and he effectively deals with the reasons you might want to use an efan - its just that hp gain isn't one. You'd almost certainly gain more by switching your tranny and diff lubes to a quality synthetic.

dejavu i swear we comment on this way too much.........

No understanding from you on many subjects eh?

This is the reason why the electric fan is a SIDEWAYS Add-on and not an UPGRADE. I like the looks of a cleaner, less cluttered, engine bay and so do many people. You on the other hand must be an old timer :)

You should go to your local community college and take some automotive classes.

Did I say that an alternator will put out max amps at idle? No.

Let's see what i said:
"The alternator does not increase amps based on RPM solely."

WOW! I said "solely". When I test an alternator while it is on a car, I rev the engine to 2000 rpms so that I can put a full load on it. Then I test it at idle and it puts maybe 50-65% of a load on it - the exact percentage I do not know.

By the way we are talking about batteries. A battery is part of the charging system - it is a capacitor and a power conditioner. If you say that a battery has nothing to do with it, then please please please go take an automotive class and stay away from car forums for 3 months.

Well isn't that something? Once again you should research stuff before you make claims, and please read posts carefully