Apparently I can not. I have done some searching and basically all I could find is set temp thermostat ones.. So I guess I'll be undoing everything and taking it back.

 

I'm thinking of removing my stock fan and installing an efan to clear up some space . this may seem like a silly question , but I have to ask.. is it bad to have the fan wired to run all the time the car is on?

 

^some people do it, i read somewhere about something wiring straight with a simple relay,.. the thing is you wont really benefit as much since you will be running the fan all the time which will put a load on the alternator. With a temp switch, it will be better for cold starts vs. full time electric fan.

 

"Bad" in the sense that you're confusing-actually, fighting against- your cooling system and not exploiting the real advantages of the efan...yes.

The whole point of installing the efan is to gain more concise control over the fan's operation.
Much of the time (and we'll assume your whole cooling system is in good, fully operable condition), you don't need a fan at all.
Pretty much anything over 45-50 MPH and just the radiator will extract the engine heat using the intake airflow...no fan needed.
In fact, the fan is actually blocking some of the airflow- just being in place, not running, but there's not much you can do about that.

When the car is cold and the thermostat is closed, you don't need the fan running...it's not doing anything but draining electricity.

After the car reaches operating temp ( with a stock thermostat, about 184°) you still want the fan off so the radiator can do it's thing.
If the conditions don't allow the radiator to dissipate the heat- slow vehicle speed or airflow blocked by a car ahead of you, say- that's when the fan is wanted.

So you make the efan come on somewhere around 190-195° and go off before it cools below the thermostat opening temp (184°).
You want the thermostat fully open as much as possible because that gives you the most coolant flow volume.
If your fan is always on, the thermostat is constantly cycling open to closed, which is inefficient. Keep in mind that the thermostat is basically a variable restrictor in the cooling loop and when it closes the waterpump is working harder, trying to force water (which doesn't compress) through a smaller orifice.

The whole trick to an efan install is finding the proper thermoswitch, one that comes on and goes off at the temp you want. The delta (difference) between those two states (on/off) is the hard part (that's called "hysteresis", FYI).

In my experience, the "probe type" adjustable thermoswitches (the kind you stick between the fins of the rad) are fairly consistent about their turn on temp but quite variable about when they turn off.
Much better are the switches that are in direct contact with the coolant but they are obviously more involved to install (there's lots of info about where people prefer to put them).

So, in a nutshell, wiring an efan to be always on is not just a bad idea, it shows that you really don't understand how your cooling loop works and the fan's place in it.

 

Great post!

 

http://www.aaroncake.net/rx-7/efanmyth.htm
http://www.aaroncake.net/rx-7/efaninstall.htm

 

This is a good thread. Thanks.


How's it working now?

 

Just to let everybody know, I am now running a Power FC for engine management and it can control an electric fan. With the Banzai Racing adapter kit it switches a ground for a relay through the orange wire on the initial set coupler connector (s4) or a different plug on the s5. The set temperature is adjustable. Usually people set it to 87 C, which is about 189 F. With that setting the fan will come on at 86 C (187 F) and stay on until the temperature drops to 85 C (185 F) .

 

rock solid so far. I recently flushed the fluids and new waterpump. No problems at all with this setup. Thinking about putting my a/c belt and getting it recharged soon, so that will be the ultimate test with the summer heat.

 

Update
The PartsMaster/Hadyen fan control has started giving me problems.. I let my buddy detail my car at his shop a few months back and a few days after that, the car started to run hot... I couldnt figure it out, installed a OEM mazda thermostat, new coolant etc..

Turns out the fan controller wasnt turning on, sometimes it would, sometimes it wouldnt.. Checked all ground spots, tested the relay and the fan. I recently ran the a/c override wire to the ignition source so right now its running all the time til i replace it.

Ive had the same unit years ago in my old 240sx and remember that these things are fragile from moisture /water.. so i figured perhaps it got water damaged from the detail job, even tho my friend says he did not get any where near it.

So today my new order came in


The Derale 16749
Typically $39 online, ordered from Summit... *was giong to order from Jegs but they had it on backorder* Derale's website says this is a newly redesigned unit... If you search google, most of the pictures of this unit looks exactly like my old hayden, so i figured most of those pictures are the older model. I suppose this new one would be totally different then my old one.

I wanted to stay away from the old one so i chose this.

This thing is gorgeous. The build quality looks soo much better. It uses a harness, and looks to be sealed better, should hold up alot better to weather. The adjustment screw is covered by a rubber plug to protect it. And the 3/8 npt probe is replaceable. Very nice quality piece for the price.





Im planing to swap this in this weekend. Looking at the wiring diagram, this thing is different then my prior setup.. This is a switch for the negative lead on the electric fan, while positive lead goes straight from the bat.

 

Installed.

Mounted it in a location that is easier to make adjustments to.


Went ahead and applied some shoe goo as a sealant around where the relay plugs into the unit for added protection, It is sealed up pretty nice. Does the job.
Now i need some cooling panels to cover it all up.

 

Lookin good. What temps do you have the switch set for?

Do you still have A/C? or P/S? cuz I need a place to mount my relays and it looks like most of your relay slots are open, mine are all rull, I'm sure there's something I can yank that no longer serves a purpose...

 

Yeah i still got A/C and PS.
Its set to kick on around 185-190 but im still tuning it with the little time i have to work on the car.

 

Great thread! I'll be using this info next week!