Originally posted by Hdbngr8:
Here is where you err, Grasshopper. The heat into the system is everything. The t-stat does not cycle as you think. Once it is full open it has no effect on cooling (other than it is a flow restriction). Its function is to limit the minimum coolant temp, not the max. Once you are past full open (assuming you are applying high Hp) now you are at the mercy of the efficiency of the radiator, ambient air temp, vehicle speed, and mass flow rate of the coolant (or engine speed). When you are not adding much heat to the engine (such as highway driving) then your coolant temp will run at the t-stat setting (assuming a clean radiator). Remember Qin = km(Ti-To). (Ti-To) is basically fixed by the t-stat temp and ambient air temp. The only way to vary the heat is to alter the mass flow rate of the coolant (remember heat is a function of the fluid, mass of the fluid, and temperature). Once Qin is greater than that which the radiator can exchange (the equilibrium temp between the t-stat, radiator, and heat in) the temp. will begin to rise assuming constant coolant and air mass flow rates and ambient air temp.



I agree that heat into the engine is everything, and if you can add more heat than the radiator can take out then you cannot control the upper limit of the temps with the thermostat. HOWEVER, I would assume (no practical experience here with the SVT) that the radiator can pull more heat from the coolant, than the motor can add. Which would lead to the thermostat controlling temps again.

I know the radiator in my S10 is terribly undersized (overheating problems in the southwest are common), and I put a lower temp stat in it to help. I can easily add more heat to the coolant with it than the radiator can pull out, so I completely understand the point, I would just think that the SVT radiator would be of high enough effeciancy to not have this issue......perhaps it is also in the same boat as my S10?

At any rate (and back to the question at hand). I can't see any downfalls to a 160* stat. When the temps are low, and the radiator can pull the heat, you will get lower operating temps which will allow for more timing without detonation. However the overall temps in the summer will most likely not be limited by the thermostat, so be sure to keep that in mind if you are tuning yourself, and leave a bit a room for those hot days.

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On the lookout for a "new" SVT.....