Originally Posted By: used_0il
If I'm reading the Infineum report correctly, 10W30 is more shear stable than 15W40.
I always thought it would be the other way around.
Especially if the story that 15W40 was originally a trucker invention by adding
SAE 50 to 10W30 is true.
I think that there's two breeds of 10W30.
The ILSAC variety, which the hot end is extended by VIIs and use a lower base oil viscosity, and the B3/B4 C3 types which seem to be a higher viscosity base oil, with the bottom end augmented by PPDs and the like...as is seen, 15W30 and 20W30 (and Amsoil's 10W30) are nearly there basestock alone.
Originally Posted By: used_0il
My Toyota test with two HDMOs, 10W30 and 15W40 posted above went over 12,000 miles each
with 1.5 liters and zero consumption observed.
At the target rate, the total would have been 25 liters instead of 1.5 liters.
With the additive package being replenished every 1,000 miles, there should be no reason to ever change the oil.
Just keep adding and adding as the miles roll by adding to the cost of motoring.
Don't forget to factor in the price of a new TWC every 150,000 miles.
That's why I don't bother with what level of adds are in the oil (and don't play ILSAC typically, and won't into the future)...don't burn the stuff, and TWC life isn't an issue...and it wouldn't be an issue for most vehicles at higher SAPS, it's just the OEMs want to protect their lemons.
Was part of the reason that I asked a few months ago if there was a fully formulated "additive" that could take (say) a hydraulic oil and make something out of it.
As to the just keep adding and adding...
I loved the M1 and Amsoil tests
http://www.brianschreurs.org/neptune.spacebears.com/cars/stories/mobil1.html which demonstrated exactly that. Take enough oil for a UOA, and a regular filter change, and the oils lasts forever.