Excellent illustrative experiment
Evil Henchman. That is what I was trying to say......
The water wetter does appear to reduce the surface tension of the water which is why it works in the experiment
evil henchman outlined. The bubbles forming on the hot surface collapse easier with reduced surface tension. In plain water the WW will definitely have some effect but the total result is still not as good as a 50/50 EG/water mix in comparision. The EG minimizes or eliminates the nucleate boiling problem you can visualize in the experiment described by raising the boiling point of the mix (not by lowering the surface tension of the water) so the localized bubbles do not form...until a much higher temperature, anyway. The WW added to a 50/50 mix doesn't show any improvement because the problem it is trying to fix doesn't exist....the nucleat boiling is prevented by the raised boiling point so the reduced surface tension (even if it existed in the water) doesn't mean anything.
Think of it like this in the experiment above. In the pot of plain water you will see the bubbles form on the hot surfaces. Add WW and the bubbles will reduce and not be nearly as evident. BUT, the pot will still boil at 212 F regardless of whether it is the plain water or with WW added. Add 50/50 ethylene glycol, however, and the boiling point will instantly increase to 240 F or thereabouts whether WW was present or not. The higher boiling point of the mixture is what makes the EG mix superior for cooling performance.
WW has a place in race and comp engines that MUST run pure water for safety/rules reasons. It should not be misconstrued, though, as a replacement nor a "better subsitute" for a proper 50/50 EG/water mix. WW just makes the plain water systems cool a little better than they would otherwise, that is all. Personally, I cannot understand their claims for making a 50/50 EG/water system work better or reduce temperatures. There seems to be no practical reason for those claims other than just marketing hype to get you to use it.
In the tests I ran the cooling systems were under heavy load (like towing a heavy trailer out of Death Valley in the summer up a 17 mile grade....been there, done that) and operating at the limit of their capacity. Adding WW did not reduce the temperature of the system which is a direct measure of the system performance at that point as it was WELL above the 'stat temperature. In systems with plain water (which I have limited testing) the WW lowered the operating temp under full load/capacity conditions by a few degrees (which might be important under some conditins) but did not
significantly improve cooling system performance like changing to 50/50 EG would. The WW worked, it was better than nothing if you had to run water but it is no panecea and certainly no subsitute for 50/50 EG/water.
I have never tested the corrosion protection claims that WW makes. I am very skeptical, though. It is difficult to get the correctly formulated OAT and silicate corrosion protection packages to work in testing and I have never seen any success with "additive" type corrosion protection poured into the systems. The OAT and silicated coolants are blended solutions that are not reproduceable by pouring an ad into the cooling system. So...the jury is out on that claim.
Possibly the corrosion protection claim comes from the reduction in nucleate boiling.... When nucleate boiling happens with aluminum heads nasty things happen. That is why you hear about aluminum heads failing or cracking on NASCAR engines occasionally. If the WW helps that it would "theoretically" provide some sort of corrosion protection I guess, but not in the overall system protection sense where the silicated and OAT coolants actually passivate the surfaces preventing corrosion.
The FJR seems to have an excellent cooling system from what I see of it. Plenty of capacity. The "heat" issues often discussed have nothing to do with cooling system capacity in my opinion. The rider discomfort comes from the hot air being improperly/poorly ducted from the radiator and/or heat from the exhaust/catalyst. The system runs on the thermostat temperature nearly all the time from what I see so adding WW or any other magic cooling system elixor is not likely to do anything other than cost/waste more money.