quote:Originally posted by Flimflam:
Fellers, anybody know the HT/HS number of Chevron Delo 15w-40? Since it is an extended drain type, I guess it must be more than 3.5, but I am not sure. Thanks in advance.
SAE viscosity guidelines require 15w-40 grades to have a HT/HS of at least 3.7 Cp @ 150C. Most commercial engine oils range from 3.9 Cp to 4.3 Cp, depending on how they're biased in terms of high/low temp properties. The synthetic 15w-40s are more shear stable, so they can be formulated down around 3.9-4.0 Cp ....
When the CI-4 spec was introduced, most 15w-40 grades were thickened up a bit to compensate for the higher temps and soot levels of EGR equipped engines...
quote:Originally posted by Jelly:
Well, I know my top three HDEO's, Delo 400, Delvac 1300, and Pennz. Long-Life all have a HT/HS of 4.3cP.
Oh, ***swoon*** I am impressed, fellers. One, by the depth of your knowledge, and two, by the sheer superb quality of the HDEO oils. HT/HS of 4.3? Offhand, the only oil I know that has better than 4.3 is Schaeffer Full-Syn monograde 30 and 40. Then again, don't quote me on that. My memory ain't what it used to be. M*1 15w-50 also has better than 4.3, but I have sworn never to touch that oil.
But it kind of makes one wonder: with performance like that exhibited by HDEO's like Delo, Delvac, and Pennz Long-life, why do people bother with full-synthetic PAO like Mmmmmmm.....like Mmmmmmmoooooo.....oh, I better not say the name just in case I start another flame war.
All the same, thanks again for the info. I am glad I poured Chevron Delo 400 15w-40 last weekend.