First let me explain; unfortunately I have not been following this thread, in part due to not planning a swap, and in part due to trying to allocate my time on the forum and not be so distracted from the work I need to do on my own projects. So it was by way of a "search" for something else entirely that I happened to land on the posts between you and Tony about various cooling fan controllers. Therefore I apologize if this is outdated, has already been answered, or otherwise not relevant.
I have a few fans going into one of my builds that I've considered various controllers for. One is a small "computer fan" for the electronics like you added to your ECU. Another is a large Spal fan added to the intercooler as Tony did. And the third would be a pair of aftermarket radiator cooling fans with the AC system interlinked. Here are some thoughts I've had for them:
The small 'computer' fan I might just wire to run anytime the engine is running. It is so small and has so little current draw that I'm not sure it really needs to be kept off at any time. And I don't see how it would have any negative effects by running across the electronic board even when it's cool? The board has the ECU, relays, injector interface, aux fuse box, etc, and will live in the spare tire well. The board itself is aluminum and I will use heat sinks on the ECU and injector interface. So a fan may not even be needed, especially if I add a grill somewhere to vent the area. But I like having the extra insurance of a fan.
The intercooler fan may just need a simple temp probe/relay set up like one of the inexpensive generic radiator fan control units (the probe could be installed on the intake air tube). Or it might even be wired to also run continuously, because it also circulates air through the engine bay (ducted to keep the turbo heat away from everything else). So there may be some benefit to it running all along? Or I might have a "after run" timer to keep it running for a specified period after engine shut down to help cool the turbo? Or any combo of those. I'm not sure what options the ECU I'll be using has for this. It would be nice if the IAT switch could control it. And even nicer if the ECU can also do a 'after run' function. But I'm planning to use a MicroSquirt that is fairly limited this way.
The two radiator fans can be split, one controlled by the typical temp switch in the rad, and the other switched by the AC control. Or they can both be wired through a two-way temp switch in the rad; one coming on at temp 1 and the second also on at temp 2. Or I could use a more sophisticated controller like you discussed to ramp them up with temp and add fan speed with the AC on. Again, not sure what the ECU can do here.
Have you found any pros or cons to any particular arrangements? Any luck with the aftermarket controllers? There are all sorts of simple/inexpensive temp controllers that might work. I know a couple of companies make specific cooling fan modules that are capable of doing almost anything. I used one on another vehicle once and really wasn't that impressed with it. Plus they are really expensive and I'm not sure necessary. I'm leaning toward keeping it simple, even if not 100% ideal in the optimal world. But I'm open to thoughts.
