521 electric fan

[ariascarlos1990]

what year?

[jovial_cynic]

Here's the article from the dime quarterly: http://dimequarterly.tierranet.com/articles/tech_rabbitrad.html

Edited April 11, 2009 by jovial_cynic

[ariascarlos1990]

Cool. This might be helpful to someone

[jovial_cynic]

Here's a handy wiring diagram for wiring up an electric fan to a radiator with a thermostatic switch (true switch; does not produce voltage). If your radiator hookup produces voltage, this wiring will not work, and might cause problems. Make sure to test your radiator hookup with an electrical tester and find out before you go wiring things up.

 

 

 

* Above the relay and below the battery is an optional light. I like knowing when my fan is going (I'm the guy that's got a hundred gauges, lights, and toggles on the console), so I'm wiring in a light that'll turn on when the radiator switch kicks over. The fan and the light are on the same line.

Edited April 14, 2009 by jovial_cynic

[oe3]

Is there a way you can make the fan speed adjustable? Mine sounds like a leaf blower when it's going which I really think is overkill on anything but the hottest days in stop and go traffic. Even a high/low toggle switch would be better than having to listen to my fan some days.

[jovial_cynic]

I know that with little computer-case fans, you can adjust the fan RPMs by adjusting the voltage going into the fan. I don't know if large radiator fans work the same way. It'd be additional wiring, and some resistors, or maybe a rheostat.

 

Is your fan *always* on? It's only "overkill" if it's running when the engine doesn't need be cooled down. If it's always on, a temp sensor switch is the solution, not a slower fan.

[oe3]

Currently mine is an always on, just a toggle switch. I toggle it by myself if I get on the Hwy and as such my worry is that I will forget one time and not realize it.

 

So that being said I plan to automate the on-off portion. My rad is pretty efficient though, on a moderate evening it'll pretty much take care of the heat in anything but a traffic jam. If I could slow the fan down a bit so that at a stop light it isn't so loud it would be nice. If it could be adjusted for those crazy hot days though it's the best of both worlds.

 

I agree, automating the on-off is the first step, adjusting the speed would just be a nice add-on. This is the ideal solution http://www.spalusa.com/store/main.aspx?p=itemdetail&item=FAN-PWM-V3 but I'm cheap and don't want to spend $200 on a fan controller.

[jovial_cynic]

... that's not ideal.

 

Ideal is just a thermostatic switch in your radiator and a relay off of that to turn your fan on/off when it's needed. If your fan is that loud just from blowing (as opposed to bearings or whatever), it might be doing a decent job keeping the radiator cool, in which case if it was automated, it wouldn't need to stay on for very long.

 

If you can't find a radiator w/ a temp switch, one of those probe-style switches will work just fine. the wiring is quite simple -- just do it. You already have an electric fan installed, so most of the work is done.

 

edit: I have seen some two-stage fans online, but I believe you'd have to connect it up to two temp switches, one that switches over at a higher temperature (ie., only triggers the high-RPM on the fan when it gets SUPER hot). But there's no reason your engine should get that hot unless you're racing it... but if you're racing it, the airflow from the motion of the vehicle would be greater than a fan could provide anyway.

Edited April 17, 2009 by jovial_cynic

[oe3]

Yeah I've got a nice aluminum rad so I don't want to replace that so at the most basic the probe or inline sensor is my best bet for a reasonable price.

 

What are the downsides of the SPAL controller? Its automatic variable speed, adjustable for on off temp, should be able to use the existing temp sensor in my sr and pretty much made with my fan in mind (It's a SPAL fan). Is this just a case of overkill?

[jovial_cynic]

Well, I *personally* feel that it's overkill. Your goal appears to be to decrease the noise coming from your fan. That's fine, and aside from the noise, I don't think there is much usefulness in lowering the RPMS on your fan. Dropping $200 on a variable-speed controller for your noisy fan seems like trying to kill an ant with an elephant gun. For $15, you could grab a different fan from a JY that isn't so noisy.

[jovial_cynic]

If you REALLY want a fan controller, all you actually need is two thermostatic switches, one set to a higher temperature than the other, and run relays off of them and have the lower-temp switch run through a resisitor. You could that for under $20. Or you could pay somebody else to do it. But you don't need to throw $200 at such a project.

[oe3]

My main goal is to get rid of the manual switch, the leaf blower issue was just a 'while I am at it issue'.

[jovial_cynic]

If you need any help wiring it up to a temp switch and relay (you really want a relay), let me know. I put together that diagram, but I could explain more in depth if you have any questions about it.

 

I think that once you have a good temp switch on there, your fan won't be running very often, and it won't really be an issue. The leaf-blower issue is likely just because you have it running all the time.

[ariascarlos1990]

I think the SPAL controller adjusts the speed of the fan to the temp. of the radiator. like when the radiator is super hot it will give all 30amps out at to when you have the car running for 5 mins its only putting out like 10amps to the fan.

[jovial_cynic]

well, it'll give out more or less voltage, not amps.

 

The fan *draws* amperage. The controller doesn't *push* amperage. It regulates voltage.

 

Anyhow, I still can't think of an automotive scenario where such fan RPM control makes much sense. The ideal scenario is that the use of the fan prevents the engine from getting that hot in the first place, in which case that upper-temp high-speed fan should never be used. As has been noted a few times, the only time overheating is really an issue (for most drivers) is when the car is idling in a traffic jam. A standard thermostatic switch should take care of that. If the radiator gets "super hot" as you describe, you might be describing an engine that has other issues that a fan controller won't help.

[ariascarlos1990]

amps-volts same thing. :D

[jovial_cynic]

except amps are what kill you, volts aren't. it's handy to know the difference.

Edited April 17, 2009 by jovial_cynic

[oe3]

If you need any help wiring it up to a temp switch and relay (you really want a relay), let me know. I put together that diagram, but I could explain more in depth if you have any questions about it.

 

I think that once you have a good temp switch on there, your fan won't be running very often, and it won't really be an issue. The leaf-blower issue is likely just because you have it running all the time.

 

 

Yeah I saved your diagram already :P but I will certainly let you know if I get stuck. It seems pretty straight forward though.

[jovial_cynic]

oe3 - cool. Do you know how relays work? My diagram is very straight forward if you have a standard relay and if you know how they're supposed to be wired. I'll be glad to walk you through that if you need any help.