Fan programming for Drag Racing

[oztracktuning]

I have a 160 F thermostat fitted now and want to program my fans to keep start line temp at about 82 deg C.

BUT i want the fans to be turned off at launch and not come on during the run. How can i do this most effectively.

I also have manual control of the fans - if i need to use it. They come on high if switched on.

[jsttry]

How did you wire up the manual control?

[SSpdDmon]

My guess would be to set the turn-on temps for BOTH fans at 83*C, the turn-off temps for both at 76*C, change the turn-off delays for both (G0907/G0916) to 0.0 seconds and set G0920 to 1km/h. The G0920 setting will turn off both fans once you start moving unless the coolant temp is above the 83*C threshold.

[oztracktuning]

The auto electrician did it with an extra relay. They both come on flat out and the switch turns them on or off independent of key position.

[Garry]

Please excuse me if this is a stupid question - as far as I understood it, you put in a lower 160 degree thermostat to get the fans to start at lower temp without being required to change anything else ... with EFI, it looks like I can control it via the PCM - so, can I just reduce the turn on and off temps by 20C or so to get the same result?

[oztracktuning]

The thermostat thats stock will not open until 90 C so its no point having the fans go on at a lower temperature than that. It would be fighting a losing battle.

So getting the 160 F thermostats lets us win the battle when the temps are set to come on at 83deg C or so to target a ECT of 82C