You are correct (and I said so) when the t-stat is open it doesn't become a player anymore (if the holes are the same size). I should clarify that different t-stats have a different hole size. The 160F Stant had a much smaller hole than the stock one. I have removed the t-stat entirely - for what I do it is perfectly fine. I agree that w/o a t-stat your temp. range will likely vary more widely depending upon how you drive the car.
