Spal Fan Wiring Question

[CincinnatiKid]

Allow me to clarify, I meant remove the resistor pack from the old aux fan and wire it to the new aftermarket fan

Could you not just run the #85 wire to High and Low temp, that way the fan would switch on at both temps?

[Adrian_Visser]

Yes.



if you remove the resistor, you will loose low speed as that is what it is installed for. ;) To wire the fan the same as stock, it will need a resistor, just like the stock fan has.

Allow me to clarify, I meant remove the resistor pack from the old aux fan and wire it to the new aftermarket fan

I recommend powering the fan from a constant source rather then switched. This way the fan will run after the car is turned off until the temp is cool enough for it to turn off. IF you run it switched, then it will turn off with the ignition.

Also, to run an override switch, just run one terminal of the switch to ground then the other to the same terminal that the thermo switch is hooked to.

What's the point of having the fan run when the car is off though? all you will be doing is cool the radiator since coolant is no longer flowing through the engine.

[BMWTurbo]

OP probably null and void now, but you could use a pair of diodes on the temp switches outputs (If in fact teh temp switch does drop continuity across the 'low temp' switch when the high temp closes). This will mean that you won't get any cross talk between the outputs and everything will operate as per factory, but you'll be able to switch the thermo on with the lower trigger point.

I'm personally not a fan of constant feeds to fans as they 'can' switch on by themselves and kill your battery. An engine fan stops when the engine does, so why would a thermo have an issue if it stops with the engine also.

[AndrewBird]

I recommend powering the fan from a constant source rather then switched. This way the fan will run after the car is turned off until the temp is cool enough for it to turn off. IF you run it switched, then it will turn off with the ignition.

Also, to run an override switch, just run one terminal of the switch to ground then the other to the same terminal that the thermo switch is hooked to.

[bimmerteck]

Has anyone wired up an aftermarket fan to run on two speeds like the stock aux fan?

Yes.

If you were to remove the resistor pack and wire it up to the aftermarket fan the same way as stock shouldn't it run the same way as the stock aux fan?

if you remove the resistor, you will loose low speed as that is what it is installed for. ;) To wire the fan the same as stock, it will need a resistor, just like the stock fan has.

[Adrian_Visser]

Has anyone wired up an aftermarket fan to run on two speeds like the stock aux fan?

If you were to remove the resistor pack and wire it up to the aftermarket fan the same way as stock shouldn't it run the same way as the stock aux fan?

I have a 2360cfm Flexilite fan that I'm going to try and wire this way. With the lower temp 80/88 degree switch of course. The recommended fuse for the Flexilite fan is 20 amp so the the 30 amp high speed circuit will be more than enough.

[sarcasmkillsme]

If you use the stock aux switch, which isn't a good idea. You must tie the low and high switch wires together. If you use just the low temp switch, if the temperature rises high enough to activate the high temp switch, the low switch opens. That would turn off the fan when it is most needed. If you tie the wires together, there might be a problem with the aux fan control. I've not looked at the wiring diagrams to see.

The standard aux fan operates at 91C & 99C. The low side is really too high and you should use a switch that operates a few degrees above the thermostat rating. For the stock 80C thermostat a thermo switch rated for 82-83C is what you want. BavAuto and other places have that thermo switch.

To add a manual control you'd run a wire from #85 above to a toggle switch and from the switch to ground.

Based on this diagram, why would the low switch open once the high temp closes? Why wouldn't they just be open at the same time. I'm getting conflicting information about this.

[CorvallisBMW]

Just mount the fan on the A/C condenser, where the old stock unit was located. Easy.

[Bearmw]

Thanks for the pics and what not but I'm interested in mounting a Spal with the intact (functioning) AC system and E28 radiator. Who's done that? Any pics?

[jlevie]

If the load didn't burn out the wires, I suspect it would burn out the thermo switch. You need to use a 30a relay (and fuse) to control the fan power.

[CincinnatiKid]

Bumping this thread because I'm doing this, but my question is can I just run the power to both the high and low side of the radiator fan switch, then ground the fan or would it overload the aux wires?

[Jaxx_]

I used the factory AC fan bracket and I'm using the OEM fan switched via a toggle inside the car(eventually I'll use my megasquirt to handle this) to close to high speed blk/green, in place of a thermo switch.

There's some space between the fan and the radiator, of course, but it works well enough to cool it down to close the thermostat even idling in traffic. Granted, I don't drive the car on the street much, but it is nice there as a safety.


Maybe that explains things a bit better.

[Frog]

^ sure thing. I really can't emphasize how sturdy these are. I am really happy with how it turned out:

[immajackuup]

I used SPAL metal fan brackets, they worked great! Very very sturdy and neat! They slide into the fan's holding slits.

Link

Pretty simple, I only used 3 of the 4 brackets, and I just drilled a hole into the top flat vertical metal part of the radiator. I then just cut the extra length.

can you show pictures of your custom electric fan conversion?

[Frog]

I am putting an m30 in my E30 no viscous fan and the AC intact and using the Spal as a pusher. What's a good way to mount the fan in this scenario?

I used SPAL metal fan brackets, they worked great! Very very sturdy and neat! They slide into the fan's holding slits.

Link

Pretty simple, I only used 3 of the 4 brackets, and I just drilled a hole into the top flat vertical metal part of the radiator. I then just cut the extra length.