How do the stock electric fans work?
 

I mean, I know they are an electric motor connected to a fan :-)
but what I don't know is how they work with multiple speed.
I have just installed a Blitz FMIC and a Koyo, and as you can read on various threads (I did it before buying and installing them, so I knew what I was going to find) they do not fit with on a R1 because of the second oil cooler copper pipe.
So I had to get a set of 12" Spal puller fans, that are a lot thinner than stock.
The problem is in the electric connections.
Spal one has only two wires (4 in total for the two fans) instead the stock one has 4 (8 in total).
I guess the 4 wires on the stock has something to do with multiple speed, I tried to power up two wires on the stock and it runs pretty slow, the same speed I get, if I power up the other two, so I guess this is speed one, and maybe if I power up all 4 of them I get speed 2, but what about speed 3??
Do they run on lower voltage on speed 1 and 2 and maybe on full voltage on speed 3? I did not had the time to connect a multimeter to them but will do it very soon.
So I guess I can connect one fan too a couple of wires and the other one to the other two.
I my opionion I will get one fan to come on at speed one, both at speed 2, and both at full voltage on speed three.

Has any of you replaced the stock fans with aftermarket ones?

Suggestions?

thanx

there was a thread about a testing a bunch of diff. radiators with diff. fans with a fmic installed. fluidyne, stock, 30% more than stock, alum. koyo, brass and copper koyo, competition. The fans were miata, mech. and auto, flex-a-lite, and some other fans. It displayed a temperature graph with the every radiato/fan combo. The coolest led out to be the brass and copper koyo radiator with a flex-a-lite fan. Well your best bet is to buy a flex-a-lite fan(expensive but worth it) and have it manual switch to it.

But to answer you other question with the stock fans... you have 4 fan relays. They're located right above the stock airbox. (passenger side) I know a thread that shows how to ground 2 of the relays and your fan will come on anytime your ign. is on. It will be at speed 1. When your fan would normally turn on due to waterthermo switch... instead of speed 1 your fans go speed 2. Then turning on your ac... instead of going to speed 2... it goes to speed 3. IN OTHER WORDS.... your fans are set one step higher at every setting. I printed out the documents from the link and have the papers in my car, but its downstairs in my garage... Ill post you the link to this site tomorrow morning when i wake up :)

I already have the mod to switch on speed 1 or 2 at a choice.
But my question was different, I understand the testa that had been done but I guess they were with a manual, simply on-off switch.
Instead I 'd lije to keep the stock multiple speed or kind of.
Uh! always forgot about the time over there.....

testa=tests (a is next to s) always try to write without looking at the keyboard...

You can alter the speed of the fans by changing the voltage that they are receiving. The two sets of wires coming out of your stock fans are connecting the same motors to different outputs from your car's electrical system. The only difference is the voltage that the fans are seeing. I would not recommend using the factory fan wiring with your fans, because they were not designed to work together.

You're probably much better off using a temperature-controlled switch to determine the speed of your fans, check and see if Spal offers those also. You can set your temp-controlled switch to turn on at certain temperatures, this is much better than just hoping that the factory system will control the stock fans the way that you need it to.

Look at the wiring diagram if you really want to find the best solution. EDIT: Actually, the above post is probably right -- an aftermarket controller is probably better than what I am describing here.

I tried to connect an IC fan (controlled by a separate relay) to the stock relays once. I had two wires with diodes in them (to prevent one relay signal from "leaking" over and turning on another relay) connected to two of the relays. However, my mistake was that I connected my wires to the high current wires on the relays, when I should have connected them to the low-current wires. The problem with the high current wires is that they don't give 12V. The signal wires should give a full 12v to turn on an external relay.

I believe that you could get a simple on/off signal (to control your fans) by tapping two of the relays. If you have two fans, perhaps you could find a way to support 3 levels of fan operation. both off, one on, both on.

-Max

I believe the switching speed on the fans is done by a resistor in the fan motor itself. Apply 12v to one wire, you get full speed. Apply 12v to the other wire, it goes through a resistor and gets turned down to a lower voltage (probably 9v) so the fan runs slower.

That said, you could probably use the stock relays to run the new fans, but unless you figure out a resistor setup for the new fans it might be a bit clunky.

Do some research on HKS' fan controller. It's a small turbo-timer-sized box that gives you total control over 2 fans, you can set what point they switch on and off. REAL neat unit. About $180 or so.

Dale