I just made the switch from a water based coolant to a waterless coolant in my RC51 and CBR1000RR. Last spring I upgraded my RC51 cooling system with Turn One radiator shrouds, Samco silicine rubber hoses and Spal pusher fans. I also switched to Engine Ice coolant. I had done some research on the internet and found that Engine Ice was propylene glycol based as opposed to conventional anti freeze which is ethylene glycol based. I found that propylene glycol is non-toxic which I liked. The Engine Ice ran about the same as the original coolant did temperature wise.
I ran across a company called Evans Cooling Systems that was promoting a propylene glycol based waterless coolant and they had a product called Evans Powersports Coolant which is compatable with smaller engines. Their NPG product is for larger truck engines. I also found that Jay Leno has been using the Evans products in his collection for years, so this Spring I have converted my bikes over.
The primary benefits of the waterless coolant is that it protects down to 40 degrees below zero F and boils at 375 degress F and therefore is a superior medium as a coolant. Additionally, having no water in it, it is a lifetime coolant because it will not corrode the cooling system and it doesn't break down. Also, having no water in it, it doesn't pressurize the cooling system and is much easier on the hoses. I'm told you can remove the radiator cap when the engine is hot, but I've not been brave enough to try that one.
With the boiling point of the coolant being much higher than any local hot spot that will occur in an engine, there will be no local flashing to steam that can occur with even pressurized water based coolants. Another problem that is eliminated is cavitation at the water pump. As a coolant near it's boiling point is run through the water pump, a pressure drop can occur that can cause water based coolants to flash to steam, resulting in the the pump cavitating and loosing efficiency.
Remembering my Thermodynamics, cooling depends on the efficiency of the cooling medium, not the speed at which the coolant is being run through the system. For heat transfer to occur, there must be contact to promote it and since any local boiling is eliminated, no matter how hard the engine is working. If an engine is run hard enough to get the cooling system to 375 degrees, there will be a lot of other things that will go wrong with it before the cooling system fails.
I haven't had a chance to put many miles on either bike yet, but so far there have been no problems. The temperature runs about the same and it starts to drop back as soon as the fans kick on in heavy traffic.
I'll post some more information when I've had a chance to put some distances on the bikes.
'12 KTM RC8R
'11 CBR1000RR Repsol
'65 CB77 Vintage Road Racer