Don,
But why then does the ad on the Breathless site state: "Prolong engine life and increase HP by lowering you engines operating temperature " Oh, maybe to aid in selling these things?
The way I see it though, which might be all wrong, is that the lower range thermostat simply allows the engine's coolant to recirculate more rapidly whereby it is cooled more by the radiator, thus actually reducing the engine's (latent) operating temperature.
As I recall, British Thermal Units (Btu) is the precise measurement of
energy required to raise the temperature of 1 pound of water 1 degree Fahrenheit when the water is near 39 degrees Fahrenheit.
The engine's coolant transfers the excess energy created by the engine during the combustion process and then re-transfers it from the coolant into the air while being pumped through the radiator...
The thermostat simply controls the flow rate of the coolant through the engine and radiator, which determines how much "cooling" is achieved?
One other thing... If the heat is still in the engine block, why would the intake manifold be cooler?
Maybe this is just way beyond my inferior abilities? It has been a LONG time since I studied physics...
Don't judge me too harshly!
Ed