Water Wetter. Just added it to my coolant fill tank. After about a week I noticed 15-20 degrees lower at speed and 10 degrees lower at idle after a Pro Solo run. This is why I put it in. I was concerned with the H2O temp climbing after a run while waiting to stage for the next one.
Redline says you can get up to a 30 degree drop and I believe you would if you increased the water concentration as they recommend This shouild be OK for summer operation and I intend to do this next summer on the circuit. One must always remember to increase the Dexcol ratio after September in Northern Climates to prevent cracking the block and heads and blowing those freeze plugs out the side of the block.
I am also looking into a product called Motor Max; it is not a water wetter but a cooling system additive that is supposed to enhance the thermal transfer of the coolant. It's supposed to eleminate hot spots and increase the heat sink capability of the coolant in the engine. It also increases the thermal transfer in the radiator. The net effect is to drop engine temps and oil temps, plus quicker warm ups and a more even temp distribution, cylinder to cylinder. I am asking the company if it can be used with the Dexcol and/or the Water Wetter. I'll keep you informed.