Re: What's the best Coolant/Antifreeze to put in my Duc. (Gilbertl)
You reduce operating temperatures when you increase the percentage of water in a water/anti-freeze mixture. Plain distilled water has twice the heat transfer (cooling) capability compared to glycol-based coolant mixes, but shouldn't be used alone (100%) as a coolant. It lacks corrosion inhibitors and water pump seal lubricating properties. So, even though water is the best choice for transferring heat, cooling systems are designed using 50/50 ethylene glycol because water alone freezes at 32°F.
Silkolene Pro-Cool, Engine Ice, Liquid Performance, Sand Evans NPG are coolants formulated with propylene glycol that is less toxic, and consequently environmentally more friendly than ethylene glycol installed at the factory by most manufacturers. Engine Ice is simply propylene glycol premixed 50/50 with de-ionized water. There have been anecdotal reports of accelerated wear of water pump seals on engines cooled with Engine Ice, but this seems unlikely to be caused by the coolant itself.
Even though propylene glycol has a higher boiling point than ethylene glycol, when mixed with water it is less effective in both removing heat from your engine and transferring it to your radiator. So, it seems that the only logic for using it is to minimize coolant discharge to racetracks, not for reducing operating temperatures. Glycols are slippery and hard to clean off the track since it doesn’t evaporate quickly like water.
Evans NPG is non-aqueous propylene glycol (i.e. that is not mixed with water.) It has a higher boiling point of 370°F that is said to reduce vapor blanketing at engine hot spots for more efficient heat transfer. Also, since it doesn't contains any water, it should be safe to use in bikes having magnesium cylinder gaskets, body parts and wheels.
Dex-Cool is an ethylene glycol based coolant that contains corrosion inhibitors that are said to be longer-lasting and less abrasive to water pump seals than additives used in other products. Probably a good product for owners who will never think to change their coolant. This is a new technology that hasn't seen much use in motorcycles mainly because they see lower annual mileages than automobiles. I use it.
Prestone 50/50 ethylene glycol/distilled water premix (or similar products) that are silicate-free are safe to use with aluminum radiators. A gallon of premix is a quantity more than you'll need for a motorcycle, saves you the hassle of getting distilled water, and is proportionally priced compared with the straight Prestone gallon container. Your bike's cooling system was designed to work best with this coolant type and mix proportion.
If you regularly experience high temperatures at speed, have a heated garage, or live in a place where you don't see freezing temperatures, consider using Red Line WaterWetter, especially for track use (where it is usually mandated.)
Water Wetter is often used because it reduces the surface tension of water (the property that makes it bead-up) thereby improving further water's superior heat transfer ability while also adding the necessary lubricants and corrosion inhibitors. Lowering the cylinder head temperatures in a high compression race engine lowers the already-high fuel octane requirements. A Water Wetter/water mix has a slightly lower boiling point than a 50/50 glycol mix and alone provides no antifreeze protection. It can be used in combination with antifreeze.
Most important, Water Wetter will reduce coolant temperatures under all operating conditions. It's easy to see its advantage in modified engines having increased heat loads, and under high-load, high-rpm track conditions. It's important to note, however, that for normal street riding in cooler and moderate weather it also can prevent the coolant from reaching optimum temperatures. Across-the-board temperature reductions of 15°F under all riding conditions are commonly experienced using Water Wetter.
Water Wetter is often used as an alternative to glycol/water mixes, primarily in racing applications. Ethylene glycol based coolants are illegal in road racing because they make the road surface slippery when spilled. Propylene glycol based coolants, however, are allowed in AMA, CCS and FUSA road racing. NESBA (advanced group) and WERA (although it was legal prior to 2002) do not allow propylene glycol use.
As others have suggested, may sure you use an anti-freeze that contains rust inhibitors that are free of silicates that can damage water pump seals. Modern water pumps use a ceramic seal that only needs a fluid to cool it. Coolants containing silicates (finely ground quartz) are too abrasive and prematurely wear-out a ceramic seal.