optimal engine fan turn on temp? opt oil temp?

[onosqv]

Hey guys, I'm trying to figure out what the optimal temp to be for the electric fan to turn on and off on my 89 240sx SOHC is.

I am running altima dual fans & koyo aluminum radiator and the engine is on Valvoline SynPower. It only has modest mods for the time being (intake, pulley, header, cat, exhaust). It will be running turbo coming summer or fall.

I will be installing an oil temp, probably a water temp also, and wondering what would be the optimal degrees those should stay at.

So far, I am thinking either the Summit Racing 180 on / 165 off thermostat controller or the adjustable one. But I don't know what to adjust to. Currently I have it set on approx 195 or so (can't tell because my hayden doesn't have a gauge or show the temp setting very well, just approx mid of cluster gauge).