What do you guys recommend? My car is set up for street/autox/drift. This winter I'm going through and adding an electric fan. Any input?
Billy

 

Did you read the FAQ?

After that, read this:
http://www.aaroncake.net/rx-7/efanmyth.htm

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

 

yeah bro only go electric fan if you need the room for intercooler plumbing. rockauto.com has the factory fan clutch for cheap if yours dies... thats where i got mine.

 

Even someone without an intercooler might want to apply more precise control over the cooling system than the OEM blunt hammer approach provides.

 

Oem works fine. for near stock anyway. "precise control" car hits about 200F starts cooling down. whats so "precise" about that? car needs to get to that temp for seals to expand. i can understand aftermarket builds in the racing scene. but the oem "blunt hammer" does a damn good job. Only reason why we went to electric fans was for space. starting in FWD cars.

 

Who is "we"?

 

"we" is people who work on cars for a living for the last 12 years. or factory engineers.

you have a high post count so i know you at least know enough for a good debate :-)

oem factory clutch fan shuts off (freewheels) when the temp drops below 180ish. give or take. almost same design as a sensor in the radiator telling the cooling fans to switch off.

Ill give you the percise control though, as with anything electrical it can be controlled. and you dont have that annoying drag noise when you rev the motor.

 

Let's look at it this way.
The normal FC thermoclutch is now 20+ years old, how many of them do you suppose really freewheel or progressively lock up?
It's a $240 part from Mazdatrix.

On it's best day, the thermoclutch isn't reacting to coolant temp at all, it's inferring coolant temp from the radiator waste air and has no direct contact with coolant..
In a very real sense, the fan doesn't know/care about the coolant, it thinks it's job is to keep the air around it's bimetallic strip cool- if that affects the water temp, then so be it.

I'm actually surprised the FC did not have electric fans from jump.
The RX-7 was an expensive halo car clearly in love with electronics...we have a solid state module controlling the horn, fer crissakes.
If, as is commonly bruited about here, the rotary is more sensitive to overheating, why did the engineers pass up a golden opportunity to address the issue?

My experience with a daily driven NA shows that the fan-any fan- is only needed about 40% of the time.
On the highway, regardless of ambient temp, air movement alone suffices to cool the car. This condition however is the worst case scenario for the thermoclutch fan. At speed, with high airflow through the radiator, the heat exchanger is operating optimally...it's extracting maximum calories from the coolant, so it's waste air is going to be hotter. The thermoclutch senses the hot air, locks up the fan and is busy trying to adjust the water temp which is in reality, just fine. The mechanical system's single reference input (the temperature of it's bimetallic strip) is not sufficient to properly react in common conditions.
Below @50°, even in traffic, the fan rarely activates.

So, faced with the probability that you need a $240 part to imprecisely control temp, why doesn't an efan look like a better option?

 

The stock fan thermo-viscous clutch NEVER freewheels. It always spins a minimum of 35-40% of the shaft speed at 'freewheel'. It never spins more than about 85% of shaft speed at 'lock-up'. This is the nature of the beast. Look at the FSM specs or the specs of any visco-clutch in the market. This is why engineers have developed the electric-clutch-type-visco-clutch.

 

Ok, I switched to a standalone from Haltech. I have a I/O for a fan. I want to use it. This is a track/street/autox car. I'm going electric fan and that's period. Just trying to figure out what is best.

I hate the way the clutch fan sounds when revving. I'm also switching to v-mount after this season.

 

Any specific recommendation would be predicated on what radiator you have.
In general, I'm a big fan (oooh, a funny!) of OEM units.
The Taurus fan is probably the most popular/common but Volvo has some cool units (nice bypass flappers) that may fit your particular radiator better.
I would definitely go with a large two-speed setup rather than two small single speeds with staged startup.

Any number of ways to activate (in your case, the Haltech) but put in a manual override in case the trigger/sensor fails (this happened to me once).

 

I would look into the volvo unit specifically because of the bypass flaps.

I had a taurus fan, it cooled great (I never even wired up the high speed) but the shroud was only "ok" and it drew a considerable amount of amps.

I then switched to a villager/quest fan, the cooling was just as good as the tarus (also a 2 speed fan) but the amp draw was lower. The key advantage over ther taurus was that the shroud fit my koyo like a glove after some very minor triming.

Almost too well in fact....I found that while driving around town the temps fan would keep temps in check, but on the highway they would gradually rise. It seems most reasonable that the tightly fitting shrould w/ no bypass capability prevented the fan from operating properly at speed. I was going to look into fitting some re-purpoused flappers to the shroud but I ended up going v-mount before I got around to it and I had to ditch the whole 16-18" fan idea altogether.

Whith the v-mount I have to run 2 x 10" fans which combined don't seem to draw as much current as either of the aforementioned units (they don't seem to move quite as much air either). They freewheel and bypass air just fine on the highway, but sometimes struggle on hot days (90*+) in stop and go traffic. Both of which make sense since combined they only cover about 66% of the area of the rad as opposed to the single fans whose shrouds covered the whole thing. The key difference w/ the v mount setup is the oil cooler which is no longer recieving any airflow from the rad fan, I have ordered a CPU case fan to address that and I'm confident it will fix the issue.

edit: The v-mount is completely un-ducted (aside from the stock undertray)

+1 on the override switch! I had a stock temp switch fail on me just last month, fortunately I still had the wires and switch hooked up from when I was testing the the fan so I was able to bypass the temp switch and get home safely.