NZConvertible

Yeah you're right, it's watts that are joules per second, not amps. My bad. I'm just trying to clarify that current it a rate, not a quantity. The way people talk about current would indicate a lot of them don't understand that.

It has to, or it breaks the most fundamental laws of physics. If the engine isn't doing the extra work, what is? The alternator doesn't create energy; it converts mechanical energy into electrical energy. If you want more electrical energy out you need to put more mechanical energy in. The simple proof of that is the fact that the idle speed will dip when you turn the headlights on. The S5 ECU even has direct inputs from the high-current devices (headlights, defogger, etc) so it can instantly increase airflow via the BAC valve to compensate for the extra load on the engine.

American Rice

I have one and that is all me and my buddy's use in our vehicles as I have never seen anything for that cheap that works better. I have only come across a few that were better in all actually. You can go to a car basher and get one for $15 lol. thats what I did

KNONFS

iTrader: (14)

I am having "this" issue...

A flex a lite black magic fan will keep the RX-7 coolant temps under control, even with a FMIC. The problem is that the FMIC blocks the oil cooler, and as you drive around, the oil temps will go up; as a result, the coolant temps will start to go up too

Richter12x2

iTrader: (1)

Do you seriously think that the electric fan is pulling 30 amps or are you going by what the fuse says? Do you actually run an e-fan? Have you seen one installed in a Mazda RX7, and witnessed firsthand the path of destruction that is wrought by it? Reducing all electronics to ash, melting the engine right off the mounts?

And whether they designed it themselves or not, Mazda engineers are the ones that determined that it was sufficient to their needs, right? Or do you think that someone said "Hey, we've got a warehouse full of these things that we got for 400 yen a piece, can you make it work?"

I noticed that you didn't come up with an answer to the fact that the A/C clutch and blower would cause larger voltage spikes than the e-fan would. I did notice however, that you went from saying voltage spikes are a main danger of running an e-fan on an alternator to "Voltage spikes aren't normally a problem."

Let me distill it in lowest terms. People have been using electric fans on FCs of both series for years with no long term effects, and 99% of cars produced today use an electric fan instead of a clutch fan. Wonder what the reason behind that is?

What I wonder about, is are you the type of person who's going to argue a point out of stubborness, long after his arguments have been disproven and shot down?

Richter12x2

iTrader: (1)

You're right, I can see that now - I'll buy that the extra charge in the windings electromagnetically increases the drag. I still don't buy that you can force an alternator to operate outside it's design parameters without modifying the circuity. You may be able to get it to pull more amps than it's rating says, but that's because the ratings are typically conservative. Like the horsepower ratings on Japanese sports cars in the 90's, and American muscle cars that were rated lower for insurance purposes.

Aaron Cake

iTrader: (1)

Do we really need to go through this yet again? This topic just took place a few weeks ago...

30A at the minimum to start the fan, somewhat less then that once it's running depending on the fan. The ones I use (Pontiac 6000, large GM) pull above 50A for a few seconds to startup and then hover around 20A when running.

Yes, actually.

Sufficient for a stock car. Adding a 20-50A draw to a 70A (on a good day) electrical system is not exactly stock anymore.


Because they don't cause "voltage spikes", they cause voltage drops. The AC clutch can cause a momentary spike when the field collapses since it's a big inductor, but there's a reverse biased diode across it's windings to prevent this and that spike would only occur when the clutch is disengaged.

When a big electrical load is switched on, the voltage momentarily drops as the alternator takes a few milliseconds to catch up, the BAC needs to open a little, etc. If the electrical system is marginal or overloaded, these have a big impact. Headlights dim, fuel pump slows down, etc.

For some people, that's true. For many others, there are major problems. I myself had serious issues when I first installed my e-fan due to lack of alternator capacity.

FWD.

Are you?

Richter12x2

iTrader: (1)

I guess so.

I'm using the Taurus/Escort fan - as soon as I can get a hold of an amp clamp I'll start it and run it with the jump starter and see what kind of amps it pulls starting and running.
It'd be amazing to me that the electric fan would use 2/3rds of all the available amperage of an alternator. Since the 1986 Pontiac 6000 alternator is only rated to 78 amps.

What happened? Did the alternator burn up, blow open a winding, seize up, catch fire, blow a voltage regulator? I don't doubt you, but I'd honestly like to know, since I'm doing this to my car, and I think it's important to have solid information from people who have done it rather than armchair academics.

Wasn't A/C an option on Rx7's, or was it mandatory? Did they use different alternators to account for the extra load?



I was using his terminology, to restate the question using yours, is the voltage sag that occurs when the e-fan turns on really any greater than the load put on by the AC Compressor and blower motor?

Are they written down somewhere that I missed? I didn't see it on the how-to writeup on your website that I was read. Most importantly, did it damage the alternator, or did it just cause other electrical problems because of inadequate supply?

Mustang v6 and v8, Thunderbird, Camaro, Firebird, GMC Yukon, Lexus LS430 and 470, Lexus GS300, Miata, Rx8. Those are just the RWD cars that I've personally had hands on that use an E-fan. If a clutch fan was truly better, you'd think they'd have stuck with it, especially the Camaro, that uses the same block that's been around since the '60s, so it would have actually required MORE development NOT to use a clutch fan.[Quote]

Wow, I didn't realize you were against it, Aaron, since I read your website for information on how to do it, you really ought to warn people, other than just saying that you're not really gaining any flow over the stock fan, and not much Horsepower.
To answer your question, no I'm not. I've already conceded that more demand on the alternator can put more load on the engine. If someone can provide a reasonable explanation, my views are always malleable. Unfortunately, I have a fairly well-tuned BS meter, too.

slo

iTrader: (1)

Yeah I said voltage spikes aren't normally a problem, but when the battery is low and you switch on and off a large electrical load they can damage electronics.

I have no other explanation for why my haltech died (when they repaired it they said it was a voltage spike) the car was idling, lights on and dimmer than normal with the fan on, fan switched off and thats when the car died.

I have a taurus motor in a black magic case running only low speed. The low draws over 15 amps, the high starts at 60 and goes down to 40+

Richter12x2

iTrader: (1)

Were you using your Haltech as the fan controller?

What's confusing me more now is that from the argument, you and Aaron Cake are both saying "E-fans bad, don't ever do it" but you both run e-fans, and as far as I can tell, have not removed your e-fans to go back to the stock clutch-fans, am I right so far?

Not to be adversarial, but if it is bad and there is no benefit, and you both have problems with them, why are you both still running them? Well, not STRICTLY adversarial. But obviously you both see some merit in them or you wouldn't keep them after they gave you so much trouble. They're not expensive from the scrapyard even if you sold the one you took off without waiting to see if the e-fan worked.

RotaMan99

They are not saying that at all. What they both do know is that switching to an electric fan is a sideways add-on and not an upgrade .Why? Because the motor will consume power from the alternator. Because the demand is higher, the alternator needs to put out more power which needs more mechanical power which is why it takes up to 1hp to run an electric fan where as the clutch fan can take up to 2hp or more, for moving 2500 CFM of air.

They know the benefits of the clutch as well as the e-fan. The main benefits from the e-fan is down low in the rpms, either idling or slow cruising where the clutch fan is much less effective. At idle, the stock clutch moves up to 600+ CFM of air, if you have a FMIC, this may be an issue, so the e-fan can help since it could move over 2000 cfm at idle.

ok ok, why do I keep talking about this, there are so many links and info, don't need to say any more. Click on the "Electric Fan" link below and you will find a lot of info and also info on the stock clutch fan.

Go search for info about alternators and you will see how they work. Infact, HowStuffWorks.com probubly can help you out too

slo

iTrader: (1)

Using a simple thermo switch and relay as the fan control.

I have a 13b-rew the waterpump spins backwards in comparison to the e shaft, and a fan wouldn't clear the water inlet (lower rad hose).

If I could go back to a clutch fan I would in a second.

RotaMan99

You could also use a simple voltage switch and use the OEM water thermo sensor on the back of the water pump housings to control the on-off set point for the fan and the Hysteresis, the difference between the on and off set points.

http://howto.globalvicinity.com/gv_w...=148&co=1&vi=1

staticguitar313

iTrader: (2)

less bickering more info please this is something i'd actually like to add to my car.

Aaron Cake

iTrader: (1)

Probably about the same.

Prepare to be amazed.

The fan was wired so poorly that it somehow caught fire and burned down the front of the car. It was an installation problem and not an inherent fault with the fan.

Overloading the electrical system is generally not going to cause a fire because something else will give first. It's fairly easy to pop the alternator regulator by running it at 100% load all the time, but it won't catch fire.

The AC compressor is driven by the engine, not electrically (as I'm sure you know). The only other AC related electrical load is the clutch (an amp or two) and the heater blower motor (no more load then the heater would generate). The small aux e-fan also adds a load but based on the size of the fan it's not going to be much.

Keep in mind that for S5, Mazda upgraded the alternator so it seems the thought the S4 system was inadequate as well.

Yes, much larger.

I lost an alternator but I don't know if I can attribute that directly to the fan. My issues with the fan was that I didn't have enough alternator capacity. A day of driving in hot stop and go traffic would drain the battery, and then when I went to start the car to go home it wouldn't crank. There was just not enough capacity in the stock alternator to run the blower motor, stereo, headlights, brake lights, EFI and now a big current-sucking fan. Add all of those loads up and it's likely 60-80A worth of stuff.

I could only imagine if I had been running a big fuel pump, big turbo and large injectors. I would have hit full boost and ran lean because of lack of power to the fuel pump.

Manufacturers went to e-fans because they are also easier to control with the ECU then a clutch fan. Nowadays manufacturers like to disable the fan at WOT, enable it at any time when the A/C is on, run the fan a little with the engine off (FD...), etc. Engine bays are also getting smaller and an e-fan requires less space. The clutch fan is certainly more reliable, but I honestly don't think manufacturers are that concerned with making reliable cars (otherwise they would have stopped using the 100 year old ground strap design that barely lasts 1 year).

I'm just arguing for the sake of arguing.

I'm not really against e-fans, but I'm against some of the misconceptions and reasons people use to try and make it seem like the fan is an important upgrade. As mentioned in a post above this one, it's a parallel-grade. Two parts which do the exact same thing. There are many reasons why you would go to an e-fan. I originally swapped one onto my car because my stock fan clutch died. It's still on there because it's really hard to go big-turbo with the stock fan shroud in the way. You can run an e-fan in the staging lanes at the track to stop heat soak, or keep it running a few minutes after the car is shut off to help cool things off (there is a minor heat spike just after the car is shut off since the water pump no longer turns).

My main issue are the hack-job installs, and those that claim swapping to an e-fan is a mystical source of 15 HP. Also those who believe the alternator is a free energy device and the fan does not put any load on the engine.

Aaron Cake

iTrader: (1)

Please don't put words in my mouth. I'm a big boy, I can speak for myself. Especially when I disagree...

Certainly true.

I think you have this backwards...All things being equal, the e-fan will always require more engine power to turn then a mechanical fan because of the double energy conversion. This ignores the very important considering of blade design though and assumes that both fans have exactly the same blade and shroud. The blade and shroud are instrumental in the efficiency of the fan. If the e-fan has a much better design, it will be more efficient. If the clutch fan has a better design, it will be more efficient.

It's effective enough that Mazda sold every rotary vehicle to '93 with a clutch style fan, and the FD (with it's dual electric fans) was the first one to have major thermal problems.

I have never, ever noticed a difference "down low" in an RX-7 with an e-fan versus a properly working clutch fan.

The stock fan is designed to operate best at a low RPM. The purpose of the clutch is to keep the fan around that speed when the engine is turning faster, and to let the fan freewheel when it's not needed. Obviously the clutch cannot increase the speed of the fan.

All the cars with FMIC heating problems I've seen have had aftermarket e-fans. Those few that still have clutch fans (mine used to be included in this) had no heating issues.

RotaMan99

I wasn't trying to put words in your mouth, I never said, "they said this!"

No actually what I said is what I meant. The clutch fan has the possibility of consuming more HP then the electric fan no matter what the efficiency is of the e-fan. If the motor on the e-fan consumes a measured 15 running amps, then all you have to add in is the inefficiency of the alternator. Which won't be more then 1hp. The clutch fan, depending on how much mechanical power is needs at the time, could consume more then 2hp, but that is around the max it would consume, usually it decimal or 1+.

Let me put it this way, at clutch fan moving 2500 CFM of air would consume about 2hp, an electric fan moving 2500 CFM would consume a decimal amount. Now at idle, since 2500 CFM usually is not needed, the e-fan would most definatly consume more mechanical power then the clutch fan.


You probubly wouldn't unless the limited CFM from the clutch fan down low is not enough to cool the engine, which in most cases, it IS enough.

Actually it could. The clutch is never fully disengauged, its lowest limit I think is around 20%, I would have to read up on it again, and the highest is around 80%. So if the engine is at 700 rpm, the lowest speed the fan could be at is around 140rpm, adn the highest is around 600rpm. Depending on the engine temps, the clutch would increase the speed of the fan if needed.

Your right, but at idle or any low rpm, say below 1500. The clutch fan would never be able to move the amount of air an electric fan could.

This is really interesting and I would actually like to see how many people with FMIC had cooling problems with e-fans vs clutch fan. Im not talking about putting on a FMIC after they already put the e-fan on, I woud like side by side comparison.

RotaMan99

To bring this a little further. 15a at 13v with 50% inefficency of the alternator added in (at worst), equals out to 292 watts which equals out to .40 hp. More then the clutch fan at low CFM demand but less hp when you start getting near and beyond 2000 CFM. So if you were looking at the highest CFM vs HP requirment, the E-fan would be the way to go.

You can get e-fans that move close to 3000 CFM of air for less then .40 hp. Try getting 3000 CFM of air with the clutch fan for that, you will probubly be up in the 2.5-3hp loss area.

TweakGames

iTrader: (3)

This thread hurts my head.

summary : go e-fan if you want but its nothing special.

ta da

RotaMan99

Basically. You would only gain possibly 1hp when switching to an e-fan and thats when the fan is off.

Basically, if your engine is stock or mildly modified, stick with the clutch fan. Heavier modified engines may need more air flow to cool but the stock clutch fan will most likley be just fine since the HP the engine is producing at times you would need the fan, are small.