jm@ReischePerf

Actually the thermostat will regulate the min and max temp for most conditions. As long as the cooling system is capable of dissipating the heat (ie, radiator/airflow etc) the ECT will stabilize around the temp that opens the thermostat almost all the way. However if there is too much heat being generated and the system cannot remove it fast enough, ECT will continue to climb.

papa tiger

The thermostats either 170 or 190 really cant control cylinder head temps accurately at all. Thats all about total water flow and radiator efficiency. The lower one simply fully opens sooner but once open has no effect. The higher one holds the motor consistantly at that temp. Better !

jm@ReischePerf

So it has already been established earlier in this thread that these temps are read out of the head, so obviously the thermostat does effect temps in the head substantially.

hardhat

You need it written in the tune as said before so when the stat opens the fans kick on otherwise your temp gauge will bounce up and down. It lowers engine temps thus reduces (heat soak) aka the timing being pulled to reduce detonation which when that happens you lose power. My SRT8 was horrible with heat soak and a 180 stat with a tune solved the problem in warmer temps. Not an issue when its cool outside.