I recently purchased this OBDII HUD display toy that can display coolant temp, batt voltage, rpm and mph. My intention was to read the rpm, cus my car is so quiet that I hear every other cars but mine. I was having hard time knowing what rpm I'm in so instead of looking down I bought this to see the rpm in HUD. Good idea, not so good execution.
In testing this HUD, when I monitor water temp, during normal drive the water temp goes up to around 220f and than goes down to maybe 190f and than goes back up to 220f and back down again. It seems my thermostat opens around 220f and closes around 190f(approximately, it's a $28.00 toy).
But when I drive with my heater on, the water temp took much longer to reach 220f. It eventually reached 220f and went through the whole up and down cycle but the cycle took much longer.
in track situation during hot summer days, if using heater does not bother you at all, I don't think it's a bad idea to save your thermostat and electric water pump from doing some additional work.
it's one of those things that it can't hurt but it can only help.
http://s32.photobucket.com/user/Kirk...qxxk1.jpg.html