Spal Fan Wiring Question

[Frog]

I am trying to wire up my Spal fan, I was thinking of connecting it this way:



But I also would like a switch in the cabin that I could flip to force/override the fan ON.

How would I do that?

[jlevie]

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.

[Frog]

I bought thermo switch 61-31-8-361-787 which is 80/88c.

How do I connect the switch? #85 to ground? Isn't the fan already grounded? Shouldn't it connect to battery +?

[jlevie]

In the drawing above you are supplying power to the relay coil on #86. The relay will close when #85 is grounded through the thermo switch. If you also tie one side of a switch to #85 and the other to ground the relay will close when the switch closes. With an 80/88C thermo switch, I'd suggest that you use the 88C side, even though it is a bit higher than would be ideal.

[Frog]

Thanks for the info! 88c side you mean the black and green wire?

Also, where should I connect the orange wire 'ignition switched' to? What is a good location?

[jlevie]

There should be an accessory fuse block clipped to the forward side of the main fuse box. One position in that block is switched power and the other is always hot. Use the switched side for the relay coil. Run a wire to the main power point on the right side of the firewall. Be sure to use the main power connection (big cable), not the smaller wire connection that serves the injection electronics.

Yes the black/green wire.

What size SPAL did you get? Here in the south I think that the fan needs to be 1800cfm or greater. I use a 2300cfm SPAL.

One more think. Don't even think about using the "through the radiator" mounts for the fan. They can (and usually will) eat a hole in the radiator core.

[Frog]

I don't have that accessory fuse block near the main fuse box because I have an early E30 (1984 318i). If you could advise another place, I would be greatly appreciative.

Well, I am happy I used the metal brackets to mount it, in front of the radiator (AC condenser deleted). However, I followed other r3v members' advice and went for the 16" Low profile 1300 cfm (from what you are saying, bad decision). So I will overheat?

[jlevie]

You might get away with that on a 318. I know for certain it isn't enough for an M20 on a +90 day in stop and go traffic. Under those conditions even an 1800cfm fan is iffy.

Try it and see how it works. It the engine runs hot idling or in stop and go traffic, swap it out for a larger fan. I've got a nearly new 1800cfm pusher fan if you need one (reasonably priced).

I think the next easiest place for switched power would be the coil positive.

[Frog]

^ill let you know about that fan. It is for a M50, so I am pretty sure I noobed out on the fan choice.

Ill go look for a place for the switched power, hopefully Ill find it.

[Bearmw]

what do most of you do to mount these fans properly?

[jlevie]

what do most of you do to mount these fans properly?

That all depends on where you are mounting the fan. If the A/C parts in front of the radiator have been removed you can make up mounts out of 1/8x3/4" strap pretty easily. Mounting the fan on the engine side is more of a problem. One of the aftermarket radiators has a metal channel top and bottom that can be used to mount the fan. I don't remember if it is the Nissens or Behr and it is too dark to go look at the race car to see which I used.

[dandrewg]

Is it necessary to make a shroud for the fan?

[Bearmw]

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?

[CorvallisBMW]

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 did exactly this on my m30 swap. I used zip ties to hold the fan in place, using some of the mounts from the original aux fan and some other various holes around the core support. I think 4 in total, works great and the fan holds snugly in place. Be sure to get it right up on the condenser, not 1/2" away or anything.

[Bearmw]

I get what you are saying but visuals help the most any pics would be appreciated:)