RETed

Aaron Cake said...
I'm sorry, but I have to argue against this.

I run a switch to my electrical fan, so I control when it turns on and when it turns off.

I do run an SPI electronic water temp gauge, so I know exactly what temp my coolant is at.

The only worry I have is that I forget to turn it on when it's getting too hot.  Yes, not the best of situations, but Ive lived with it for the past 3 years.

I do not trust any of the aftermarket thermostats.  They die on you, and when they do you're stuck or need to do a hasty getto rewire just to get home.

I don't know if you guys know this, but running the electric fan at high vehicle speeds (over 50mph) can actually cause the engine to get HOTTER.  You see, the fan is spinning, so it's causing more blockage at higher speed, and the thermostat does not know this.  At the very least, I can hit my switch and kill the fan and let the vehicle speed cool everything down.  Your thermostat controlled electric fan would keep the engine hot until you slowed down, when the efficiency of the electric fan overcomes it's disadvantages running at high speed.  This might be a function of fan blade design (i.e. pitch), so this might not apply to all electric fans.

With such fine control with the electric fan, I doubt ANY mechanical fan (viscous clutch or otherwise) can come close to running more efficiency, period.

I'd like to hear something more efficient than just making a blanket statement that electric fans are not that efficient.

I hope you weren't closing that other thread cause someone had a beef with your write-up on the subject.


-Ted

WAYNE88N/A

I'm with you, RETed, got a manual switch in mine, too...call it ghetto if you will, but on a normal drive to work & back (100 mile round trip), the only time the e-fan needs to come on is in the afternoon as I hit the stoplights right before I park...that's 100 miles driving, and only 2 miles in which the fan is needed...as long as the car is moving at least 40-50 mph, the temp gage stays at about 1/6, maybe 1/5 up when it's 90+ degrees out. I never understood why people put an e-fan in their cars and ran them all the time- it's counterintuitive...I'm sure it's a different story for you guys stuck in the "big city" traffic, though

j9fd3s

iTrader: (3)

well you could also wire it up so that it turns on either by thermostat, or manually. that way you can run the fan after you turn the car off, or if the thermostat fails or in case you just like to turn on the fan

White_FC

Chalk up another happy owner of an E-fan'ed Rx-7 with a manual switch.

And I saw an argument in another thread about e-fan's somehow making an engine run too cool?
I think I know who said it, but sorry I can't be bothered searching to quote..

That would obviously never happen, even if you _did_ have it running 100% of the time..
The Fan, either mechanical or electrical does not magically make an engine run cooler, that is the thermostat's job.
All a fan is going to do is get rid of excess heat..

bingoboy

are you guys doing this with factory radiators or upgraded ones?

NZConvertible

There's no guarantee that one day you won't get distracted and forget to switch it on. It's human nature, and anyone who says they'll never forget is claiming the impossible. I'm sure you are unlikely to forget, but I can think of some people who'd quite likely cook there engine inside a week. IMO cooling systems (especially on rotaries) are too important to be anything but fully automatic.
I've used several quality thermoswitches and never had a problem in many years of using them.
But it does know if you've set the thermoswitch correctly. If you're moving that fast, then the coolant temp should below the set point of the thermoswitch and the fan won't be running. If it is, you've set it too low.

You're absolutely correct about the effects of leaving the fan running all the time though. Those who run their fans constantly off the ignition should take note.
But what are the gains from your riskier manual method? A few degrees hotter or cooler as the fan modulates is going to make a negligible difference in how the engine operates. There's simply no need to the control to be this fine. All factory e-fans and thermoclutch fans react to a slight increase in temp. There is nothing wrong with this method. It has worked successfully for decades.
Nobody's claiming that e-fans aren't efficient. We all know that they can do the job required of them if they're selected, installed and operated correctly. The problem comes from the people who think this is a performance mod, or think they can skimp on costs an still expect a fan as reliable as stock.

RETed

That is correct.
Best set-up I've seen is a 3-way switch:
*ON
*OFF
*thermostat sensor controlled

That should convert all the nay-sayers.

-Ted

j200pruf

iTrader: (4)

Ted, I really like the 3 way switch idea. I still like the efan mod just for the fact that it can do a very good job of cleaning up the engine bay.

chris_stampe

Have a thermo switch and a manual switch for it. You can leave it on all the time, unless you decide you dont need it when cruising on the interstate and racing at high speeds. Best of both worlds.

J-Rat

iTrader: (2)

Hmm.. Didnt see this coming.

Aaron Cake

iTrader: (1)

That sounds like a good setup...That way you could leave it on in the pits/staging lanes to avoid heat soak.

NZConvertible

Haven't you read anything in all these threads? There's absolutely no need to leave it running like that. There are no benefits, only downsides. The fan should be off far more often than just when on the interstate or racing. In my experience with a pilot light that indicated when the e-fan was running, in normal driving it was off far more than it was on, and temps barely moved.

Aaron's staging lane suggestion is about the only logical reason for manual control suggested so far, although I think a fan pulling hot air through the radiator is going to struggle to make much difference.

BTW, if you are going to have both manual and automatic fan control, OFF should not be an option, only ON and AUTO.