Ok, I think with everyone's help we have the total picture. First the equation for heat transfer: Q=kA(T2-T1)t/d, where:
Q = the total heat transfered
k = the coefficient of thremat conductivity (this is a simplification because iron/alum and coolant have different k's)
A = the surface area
T2-T1/d = the temperature gradient
t = time
Time is in the equation, but since we have a closed system that always has coolant in it, hopefully, this is open ended and doesn't have an affect as I claimed earlier. It will come into play when the engine is producing more heat faster than the radiator can effectively dump to the air: how long until the coolant can no longer be kept liquid.
What bothered me was the fact that, very often, an engine will run hot without some restriction in the system. I think Steve got it right. The excess speed with water flowing over the irregular surfaces of the water jacket cause cavitation (seperation between the coolant and the metal surface) which reduces A and, therefore, the total heat transfered. When it comes to the waterpump, overdriving it can help until you reach the point where the impellers start cavitating which will decrease the flow.
DC is indeed correct in his comment on the increase in velocity of the water through the restrictor that Steve mentioned: this is only a localized affect.
Water alone has much better thermal characteristics (k) than anti-freeze, but steam has a very poor k. So the pressure cap mentioned by DC and the additives combine to maintain the coolant in a liquid state. Note: even a extremely thin layer of steam that exists only at the surface layer of the metal can significantly reduce thermal transfer. It will also inhance cavitation.
The affect of increased coolant flow through the block and air through the radiator is that the temperture gradient is kept as high as possible increasing the quantity of heat transfered.
Everyone agrees on the fact that engines need to be run at design temperatures and that they should reach those temperatures fairly quickly. So, it sounds like your practices have been validated Malcolm ;-)
I have used the windows down, heater on full blast on several occasions. The last time when my Stealth started overheating one eventing. I discovered that my fans were not coming on. So I drove to work sweating and picked up new sensors that go in the base of the radiator (down flow) on my way home and changed them. Next morning, guess what, I drove to work sweating again. Then it dawned on me, the reason the fans weren't coming on was because the thermostat wasn't opening to allow the hot coolant into the radiator to turn them on. My thermo didn't fail to the open! Anyone need a set of sensors for a Stealth or 3000GT? (One sensor turns on the main fan and the second turns on an auxiliary fan when the temp is just a bit higher or the A/C is on.)
PS: I have a 180A alternator so when my fans are on, they are on. They come on when the variable thermostat turns them on, the A/C trianary switch turns them on, the backup temperture switch in the block turns them on or I flip a switch on the dash. I do have an indicator lamp below the temp gauge to tell me when they are on.
[ August 30, 2002: Message edited by: Lynn Larsen ]