If the temp goes too high on my car. I've noticed that the ignition system retards spark. This was at 205-210f when I was testing aero mods blocking off part of the grill openings. Needless to say, fuel economy and performance went to hell in a handbasket when it retarded spark. I was getting MPG readings in the 30's instead of 50+ when I hit that problem.
As for closed loop, I noticed my car goes into closed loop within a block or so of home after no warmup. I guess different cars would be different in that regard.
All in all, I wish I hadn't spent the $15 on a new hotter thermostat.
Cheapy, what kind of car was it? Different car manufacturers will program that "safe mode" differently. It would be good to compile a list of cars where the hotter thermostat helps, and one where it doesn't.
One idea, modify the coolant temperature sensor so it thinks the coolant is 10-20 degrees cooler than it really is....the only problem with that is the it might effect the time it takes to shift to closed loop.....defeating part of the purpose of a hotter thermostat.
before getting a hotter thermostat check and see when your cooling fan turns on. im using the stock 180 degree thermostat on my 98 civic hx and with it the car runs around 193-198 degrees according to scan gauge. the cooling fan turns on around 202 degrees. to my understanding the thermostat will start to open at the specified temp, in my case 180 degrees.
with the 180 degrees thermostat the engine runs around 15 degrees hotter and by my guess with the 195 thermostat the engine should run around 210 which means the cooling fan will be on constantly which is a waste of power.
having a hotter thermostat will not let your engine warm up faster since the radiator is still trying to cool the already cool water or warm water.
if you want a faster warm up i'd suggest a grill block mod.