Hey guys -

Borrowed a Datalogit from a friend to play around with. Yes, I still don't have a damn Datalogit . I'm hoping Ramy can get a group buy going!

Anyhow, been messing with some of the settings. There are 3 fan speed settings - Fan1 no AC, Fan1 AC, and Fan2. I've always been curious how this worked, as the ECU only has control over 1 fan speed input.

Well, I figured it out . The '96+ ECU's have direct control over 2 of the fan speeds - they don't have the thermoswitch in the water pump housing. ECU sees the water temp from the main ECU temp sender, and controls the 2 fan speeds appropriately. Our '93-95 ECU's only have 1 fan control output - the second is handled by the thermoswitch, the third by the AC.

So, if you use the PowerFC to control your fans, it's a good idea to have the FC thermoswitch as well. Set Fan1 in the Datalogit to 85-86 deg. C or so, then the thermoswitch will kick up the speed a notch at 97 deg. C. If you have the AC on, you'll be up one more notch at high speed.

BTW, the two Fan1 speed settings work the same, AC on or off. Just set them both the same and ignore the Fan2 setting.

On the turbo transition - I've never really read a lot about people playing with the transition point. You can set the throttle percentage and RPM where the sequential system kicks in, and at what RPM it turns back off. I lowered mine a bit with VERY good results - a MUCH smoother powerband. The second turbo would "hit" pretty hard, and by lowering the transition point to about 3500 RPM, the power is much more linear. I'm sure I could fine-tune it even moreso.

Dale

 

Thanks for the new info!

If you have the FAN MOD SWITCH installed, and flip it on, then you can have instant fan speed two with the engine at normal operating temps (if FAN 1 temp is set approriately).

I have a Hobbs switch installed in the control line for the AC and it is set at 2 psi.
Thus if I need the extra cooling for a long high power situation, even if it is cool weather, I can also turn the AC on and have the fans work when boost is over 2psi.

With the FMS on an AC on; I have fan speed three when running over 2psi.
That is my manual way of max cooling.

I have the Miata thermo switch.