If so do you run it with straight water or coolant/water mix. Do you notice a difference?

 

Mix it with distilled water.

Careful though - you don't have any freeze protection without real coolant (glycol). SO. . . trips to Sand Mt. this time of year can result in a frozen radiator or worse - cylinder!!!

 

I'm running it but not at full strength to maintain some freezing protection. I didn't notice much difference, Shrouds make a huge difference in cooling, they're the way to go.