Electric fan conversion

[RotaryRocketeer]

So I already have a fan that will fit in the factory shroud with a little creative persuasion and I know it flows enough CFM to do the job, I've just got one question. Why do I see everyone using an aftermarket fan controller to do this install, instead of just getting a GM temp switch that threads into the head or intake manifold? Seems like a much simpler solution, right? Or is there something I'm not thinking about?

[SunSoaked]

That would work fine. It's going to be on or off. I use a Spal controller for my dual 11" fans. This way I can make them progressive, using only what is called for. It also makes controlling the fans much easier when tied into the a/c.

[RotaryRocketeer]

On or off is fine for me. This thing stays right in it's desired temp range with the flex fan and the cooling system is in tip top shape. Guess I'll just use the switch to ground the relay and complete the fan circuit.

Also, I'm sans a/c for the time being. Planning to just get the Vintage Air pressure switch, when the time comes, to kick in the second fan speed.

[RotaryRocketeer]

Bump for another question.

If my thermostat is a 195, I should get a switch that kicks the fans on at 210 and off at 195, right?

That's about the highest operating range I can find.

[SunSoaked]

Sounds about right. Another benefit of the controller is being able to adjust the on/off setpoints with the turn of a dial.

[RotaryRocketeer]

The deciding factor for me is the $10-20 that it's going to cost to do it this way versus whatever the controller costs. I've already got relays and spools of wire from past projects. Just out of curiosity, what did your Spal controller cost you?

[gmachinz]

Spal doesnt make their fan controllers anymore. Theirs can run the fairly cheap, low amp drawing fan motors but they never could handle high output factory fans-they had at least 3 "latest versions" of their PWM controllers with the last one having features like under and over current protection where they would just shut off if the fan motor pulled more than 25A and crap like that. Tried and true relays with temp switches is the way to go.

[SunSoaked]

Originally Posted by gmachinz

Spal make their fan controllers anymore. Theirs can run the fairly cheap, low amp drawing fan motors but they never could handle high output factory fans-they had at least 3 "latest versions" of their PWM controllers with the last one having features like under and over current protection where they would just shut off if the fan motor pulled more than 25A and crap like that. Tried and true relays with temp switches is the way to go.

Don't know about all that but, I have used it in the Arizona heat for 10+ years without issue. I have used it to control dual 11" Be Cool fans.

[SkinnyG]

I'm using a fan switch from a 1990 Ford Escort. It threads right into the head, and turns on at the right temp. Problem though - my headers melt them either "on" or "off." The third one I moved to the intake manifold and it's worked fine there ever since (though the fan turns on at a bit hotter temp than before).

Running a Windstar dual-fan unit through a Sunfire/Cavalier starter-wiring-recall-relay, also from the wreckers.

[RotaryRocketeer]

I've been concerned over whether or not my headers will cause a problem with the sender as well. We shall see.

I'll be running a dual speed single unit out of a mid 90s Thunderbird. Did my homework before hitting the scrapyard and, naturally, all the Tauruses, minivans, and Lincoln Marks were picked over. Should fit nicely in the factory GM shroud with some trimming and scribing though.

Thanks to all for the input.

[gmachinz]

Aftermarket fans dont pull current (and to an extent CFM) like OEM fans do. Factory style HO fans had really outpaced the pancake design motors of pretty much all aftermarket fans and I believe the hardcore enthusiasts tried using different fan controllers from everybody and from my experience Flexalite rated the worst and DC Controls among the highest-everybody else fell somewhere in-between. Recently Dakota Digital has a newer version out whichbis supposed to be pretty stout. I just dont care for PWM controllers anymore-the Spal unit is good-if used with any non factory fan or fan assembly-it wont handle anything serious but not everybody needs a monster fan assembly-if you have 10 years out of that Spal unit you're doing good! Spal is only 20 minutes away drom me and I've dealt with a couple of their engineers in the past and they flat out told me their controllers arent designed for factory high output fans. I had them test a brand new Motorcraft Mark VIII fan back in about 2002/03 or so and Mark K. at Spal told me that fan was the most powerful they'd ever seen at the time-and no way would they have or design a controller to reliably control it. For reference, that fan motor was designed by Siemens VDO for Ford and it needed to be stout enough to run for 24 hours a day for 10 years as explained to me from a salesman @ Siemens group who worked on the project-versions of that motor would find its way into Crown Vic cruisers so it needed to be way over stout. That fan in my squarebody in the summer on low speed would drop my engine temp from 205 to 180 in 15-18 seconds-I could watch my temp gauge drop faster than my fuel gauge with the Q-jet secondaries wide open!

[RotaryRocketeer]

Those Mark fans are something else. I was really hoping to find one, but the secret is out. They are few and far between at the yard.