This thread is old, but since I cam across it in my search today I wanted to reply. Straight water is better at removing heat in a radiator (assuming the same temperature differences in the two medium transferring heat) for two reasons: 1) Water has a better specific heat capacity than ethylene gylcol, 2) water has a lower viscosity (i.e. it mixes better in the radiator and engine). I came across a graph that was produced by Prestone that showed that 50% water/antifreeze mix has about 50% the capability of removing heat as pure water (I think this is the same value Water Wetter states) . Thus, lowering the antifreeze concentration (within the winter time limits of your geographical area) should help keep coolant temperatures lower. Below some minimum antifreeze concentration (I like to say 25%) requires the use of supplemental corrosion additives (Bars Leaks makes a water pump lube/corrosion inhibitor). Antifreeze does provide some boilover protection, however it is less than 10F as most of the elevated boiling point is provided by the pressurization of the system.
Using straight antifreeze in your vehicle can cause elevated coolant temperatures without boiling occuring. You may very well be able to transfer more heat due to the elevated coolant temperature, but be aware of the possible detrimental effects regarding the engine oil thinning. An article I read at noria.com stated that each 10C increase in oil temperature makes it act as if it was one “weight” thinner (i.e. a 30 weight oil would act like a 20 weight oil). If your vehicle tends to overheat, then you might want to consider using a thicker oil.
I do want to correct one statement made in one of the threads regarding the use of Water Wetter (someone else may have corrected the statement; I didn’t read all of the posts). Water Wetter acts as a surfactant and reduces the surface tensioni of water making it MORE likely to turn into steam at nucleation sites within the engine (i.e. typically within the coolant passages in the heads since that’s the hottest area). Nucleate boiling (i.e. creation of small steam bubbles that then collapse within the bulk stream of the coolant passage) increases heat transfer and is actually designed into pressurized water reactors (i.e. nuclear reactors) and many other systems (probably automotive as well). Water Wetter’s reduction in surface tension increases localized boiling which reduces cylinder head temperatures (which is what Water Wetter advertises; they don’t advertise lowering the bulk water temperature).