Thinking of going e-fan

[FerociousP]

Originally Posted by Pete_89T2

The spec for the temp switch shown in the FSM diagram in my post says "off below 194*F" and "on above 207*F" Since it's a switch, that is either on or off, that's Mazda's way of writing a spec with a tolerance. So in other words, it should switch from off to on somewhere between 194*F and 207*F.

That's probably a good temp to trigger an e-fan, as most OEMs run similar temps. What temp does Mazda set the e-fans on the FD & RX8's to kick on at?

I figure I can wire a toggle switch to that check connector in the circuit diagram to run the fan at will if needed.

Pete, you are correct that it is a switch, but wrong in its function. It won't switch somewhere between 195-207. It will purposefully switch on at 207, and continue to run until 195. Otherwise, the fan would just constantly switch on and off as it transitions above and below 207. Most mechanical thermoswitches (i.e. not ECU controlled fan switches) operate this way. That is why in a standalone ECU setup, you have a on temp and an off temp, specifically for this purpose.

In this case, the thermostat has an operating range from 180-203. Meaning, below 180, it is shut. Above 203, it is fully open, and therefore becomes ineffective at regulating engine temp above 203. (A 180deg thermostat is typically used when you want a 190-195 deg operating temp). The fan's job is to bring the temperature back into this operating realm, which is why it brings the temperature down from its own starting point.

FDs have a complicated "4-speed" config using variations of its two fans, while the rx8 has two fans for a "2-speed" setup. IIRC both the FD and Rx8 have settings around 207-210 with more fans/higher speeds engaging at even higher temps. The reality is, is that OEMs don't want fans running during driving unless they can help it. They'd much rather the thermostat do the regulating, which is why the temp settings are relatively high for our comfort.

Personally, on my Cobb for the rx8, i set the fans to come on at 205. On my turbo vert I kept the stock clutch fan while I had it, even with my Haltech easily able to control a fan. It just worked.