i'd also like to switch to an E-fan on my S5 TII

but i'm worried about the voltage... currently i have a Denso Supra TT pump in.. and those are notorious for being voltage hungry...

and i'll be putting in my FMIC soon..


i'm using a 13b-RE clutch fan at the moment.. (slightly diff than the TII's)

and check this:


at idle yesterday.. i noticed that the A/C's seperate fan.. was Pin wheeling...

the clutch fan pulls so much air that the A/C fan on the other side of the rad+A/C condensor was Turning...

that's some serious pull

 

Read before hand...
http://howto.globalvicinity.com/gv_w...=149&co=1&vi=1

 

They have. Many companies (FlexALite for example) make fan controllers that soft start the fan and allow speed adjustment based on temperature. Two speed fans are also common, and some cars (domestic generally) use a high wattage starting resistor.

The resistor method is probably the easiest. It involves connecting a low value high wattage resistor (5 ohms or so at 30-40W) in series with the +12V line of the fan. When the fan comes on, the resistor limits inrush current. Then a second or so later, a relay switches on to bypass the resistor and the fan ramps up to full speed. Requires two lines from the ECU to control, or a timer based circuit. I may do something like this in my car since the fan likes to create an idle dip when it switches on...

 

You say it requires to wires from the ECU? Which wires? Are you talking about a programable ECU? Very Interesting.

PWM is a good way of doing it. Just READ the specs for the PWM controllers. Some of them allow the fan to speed up quickly which will cause a spike, and then slow the fan down to the right sped. I think SPAL PWM controllers do this if I remember correctly.

 

It would require two outputs from a programmable ECU (standalone) to control. One for each relay. Otherwise you will have to do it electronically. In that case it could be as simple as two relays, the 2nd one triggered by a time delay R/C network.

But really, WAY TOO MUCH thought is put into e-fans. They have worked for many years on just a switched relay from the ECU/thermoswitch. I don't like the things like the PWM controllers because there's too much silicon to fail.

 

I got this fan allready, ordered it yesturday, I happen to live close to the warehouse

Nothing to complain about, it really does cover the radiator about perfect. The low speed draws under 10 amps on my cheap amp meter, the high speed draws about 30 steady in both cases. Spikes can't be seen on the ampmeter I have.

I would say that for the price this is certainly better than 11-20 year old used electirical part.

And it cost about the same as a new black magic (pos) motor.

 

Ok so i retract my previous statement about the stock fan cooling great even in AZ weather lately the gauge has been climbing higher than i like, and when i put the TII on the road i dont want to take any chances, i hear this taurus fan is INSANELY powerful

 

I am going to rewire my Taurus fan like the picture below... but i think i will add your resistor idea

 

i think i have a taurus fan..i need that relay ?? where can i get one ?

 

nice!
but that will take up 2 PWN's right?

 

yes, it will require 2 PWN's unfortunatly

 

a regular relay can be purchased at most automotive parts stores, just make sure you get one that is rated for the hi amp rating needed for the Taurus fan (80amps to be super safe) the typical 40amper ones will melt.


the other way to go is to purchase a fancy aftermarket fan controller from somewhere like Summit or Jegs(again, make sure they provide circuitry for an 60-80amp initial draw)

 

nice thanxs Bastard

 

How again is using an electric fan bad for the alternator? Admittedly, my understanding of the magical powers these things possess is light, so I'm trying to understand better. The alternator doesn't use a clutch or anything like the AC does, so it's always going to be spinning at its own RPMs, it's not spinning harder or faster because you've got an E-fan or a monster stereo system in it. My understanding is that it's always going to generate the amps that it generates whether they're used or not. I mean, there's circuitry in it, I'm sure, but by the design of the alternator, I would think that the worst case is that you're using all the power generated by your alternator and you begin depleting your battery while going down the road.
If the alternator in your 20 year old car dies, maybe it's just because it's a 20 year old alternator, and not that new Kenwood amplifier you put in?

 

gotcha, im gonna run it the same way but the high speed will be hooked to a temp semsor becaus ei dont htink i have enough PWNS. i might...
are you using 20/30 relays or 30/40's ?

 

Electric fans can consume 15-20amps of power. Your alternator is not always producing its max amount of current. It varys the amount of current depending on the demand. The more current it needs to produce, the harder the engine has to work at spinning it. S4 alts are 70amp alts. The stock electrical system consumes most of it and adding an e-fan or high power stereo system could easily overload the alternator especially at idle.

 

Current is not a quantity of energy, it's a rate of flow of energy (joules/sec, where joules is electrical energy). So the more energy being consumed by the car's electrical systems, the faster the energy flows from the alternator. To help you understand, compare electrical systems to water systems. Voltage is analogous to water pressure and current is analogous to water flow.

That's exactly right, and when the battery voltage drops to ~10V your ECU will shut down and the engine will die. So if your alternator can't create electrical energy as fast as it's being consumed (i.e. it's too small for the load), the battery will go flat.

 

I'm a biomedical technician, I understand current and voltage. Except electrical energy is measure in coulombs, not joules. Joules is just energy in general. That's why the thing makes no sense. An alternator is layed out like an electric motor inside. The windings and armature don't change based on demand. The engine doesn't work harder to spin the alternator no matter what you install electrically to your car.

That's what I thought, thank you. Just for grins though, I'll borrow an amp clamp when I get my car running and figure out how many amps the stock electrical system actually uses to run, and how much the Taurus E-fan adds.

 

I'm liking this mod more and more, this thing would probably even keep a car with an FMIC well under temps wouldn't it?

the only thing that i'm worried about wiring and what fan comtroller to get, somone PLEASE do a write-up!!!

 

Thats incorrect, in practical terms, disconnect your bac or if you have an older carbed car that doesn't have a bac turn it on, warm it up and then turn the lights on and watch the rpm drop resulting from the additional load placed on the engine by the alternator.

and an alternator is somewhat like a brush less electric motor, yet there are no permanent magnets, the regulator controlls the flow of current to the feild windings (an electomagnet) this is what regulates the alternators output and prevents the battery from bieng overcharged and regulates the voltage bieng produced. More magnetism = more current = more mechical force required to turn the alternator.

 

My point is that you're still not asking the alternator to do anything it wasn't designed to do in the first place, you're just going to go beyond the levels of electricity it is capable of providing. In other words, an electric fan would be more apt to damage your battery than your alternator.
And if you don't want to spend the money on a fan controller, why not just use a thermo-switch on the signal ground (not HV ground) pin of your fan relay? When the temperature goes up, the switch resistance goes from infinite to zero, current flows to ground, makes the relay and supplies battery power to the alternator fan.

 

Thats also incorrect, drawing too much current from the alternator will generate excessive heat and overtime damage the alternator and the battery. The fan switching on and off can also create voltage spikes as the alternator doesn't respond instantly.

Its easier for an alternator to generate current at higher rather than lower speeds.

 

I guess it could, if you're assuming that they didn't design limiting circuity into the alternator to limit over-current conditions and ensure it runs within the operating parameters that they set for it. I was going to give them the benefit of the doubt that the engineers at Mazda weren't complete idiots, but you can't take anything for granted, I guess.

Almost like the voltage spikes that would occur during normal operation of your car, when you turn the A/C compressor and cabin fan on and off? Oh wait, that would be more of a spike, because there's that A/C clutch to worry about, too, isn't there?

All this time I thought the problems with older RX7s catching fire were due to the pulsation damper, when it was really just the addition of a properly wired electric fan! I can't believe we've been looking in the wrong place all this time!!

 

write up? controller info, best choice?

 

Mazda didn't design the alternator, mitsubishi did. Mazda selected the alternator based upon the needs of the car that it was put in. Guess what, add a 30 amp electric fan, and you should add an alternator with 30 amps more rating.

Your doing allot of assuming.

An FD alternator in good shape will make 130+ amps (30 amps past its rating) if you draw that much. The limit becomes how much current is the field windings can draw and heat.

Voltage spikes arent normally a problem, but they are present, swithcing a very large draw on and off digitally, especially when the battery is low because your alternator is too small to begin with can generate spikes with the potential to cause damage to electronic components.