I saw the abstract a long time ago, but found free full text only recently (relax, it's in English): SAE汽车发动机英文论文2003年全辑之 (2920) - 豆丁网 Good read, but I have some issues with some claims. They say that WS is shear stable (fig 13), but the prius UOAs clearly show that's not the case. They say base oil is group 3 or 4 (page 2), but the flash point is the same as mineral T4 (table 4). Anyone?
It's possible the T-IV was synthetic as well. BITOG would have some good comparisons to other fluids on the market. 381.2 F for a flash point seems OK either way as the hottest electric motor temps I have seen reported are 325F. I did find it interesting that they were tickled pink about a 1.1 to 1.4 % economy bump from WS. Seems to prove that T-IV would protect the tranny well with a small economy reduction. All other performance specs were about even. Either way I'm changing the fluid at 30-40K intervals. Edit. Went on BITOG to check a few things seems most ATF is 350-400 flash point. The one virgin WS sample I saw was considered to be a relative match for Dextron VI. Another essay on ATF development. http://www.lifeautomotive.com/pdfs/History_of_ATF.pdf
Me too, but I'm thinking it could be slightly more in a hybrid car and a whole lot more if one does short tripping only. Besides, every bit helps. 1-1.5% is about the MPG gain going from 5W30 to 0W20.
What is WS? I am thinking (from a cursory look) that's a Toyota name for ATF fluid. Why are you worried about flash point? That's just a measure of the vaporization temperature of the oil, unless there is some thermal breakdown of the additives at play in ATF fluid, not sure.
Indeed! When tossing out an acronym for discussion, why truncate, make it more obtuse? Page 563 of the 2010 Prius Owner's Manual: I'd hazard it stands for "Automatic Transmission Fluid - World Standard".
Sorry for not spelling out WS. I thought almost everyone knew or one would check the link if one didn't know. I'm not worried, it's just better quality base oils have higher flash points. So, flash point is a poor man's way to judge quality of base oils. On the other hand, thinking more about it, WS has much lower viscosity than T4, so having the same flash point means the base oil is better quality. Mystery solved.
Every ATF that I have seen that is WS rated was labeled synthetic. Never seen a Toyota bottle though it's likely synthetic also.
