When I purchased my IROC used this year it had a 195* thermostat and hypertech thermomaster chip in it. The coolant temp was always around 170* (checked with an auto x-ray). After the car passed emmisions testing I was going to put in the 160* thermostat that is supposed to be used with the thermomaster chip, but after reading searches on the subject I decided to use the 170* (everyone said you will get almost no heat during the winter with the 160*). With the 170* the coolant temp stays around 180*. Why would It go up with a lower temp thermostat? Would it cause any problems to just stick with the 195* even though the chip calls for a 160*?

 

perhaps the 195* stat was really a 170? or its opening way to early? or it could even be your CTS is getting old.

my 180 stat keeps my car at about 175 most of the time during the winter months. remember the stat is going to begin to open a little before the temp its rated at. im not going to get into the whole "your car will run better at a higher\lower temp" etc. etc. as there are quite a few other post about that which u can find just by looking around.

however i will tell you that the hypertech chips suck. Unless you enjoy something that advances your timing WAY to much causing detonation and in the end causes your timing to be retarded to less then the stock chip. Im not sure what the "Thermomaster" chip does to the spark advance tables compared to what their other chips are like, but im sure its close.

 

I tested the 195* stat in a pot of water on the stove with a thermomitor and it opened just as it should. I wish I had tested the 170*. I just trusted it since it was new from GM and had 170 stamped on it. What is a CTS? I'm begining to think you are right about the chip, I have the intial timing set to 0* and it still shows it knocking on the Auto X-ray.

 

CTS is the coolant temp sensor. the one on the front of the block.