It is all speculations. There is no proof nor data to back up any claim. Even 10% improvements seems a stretch. Majority of early engine failures, slug etc. are inherited in design and whatever oil used makes no difference. Even 2% better mpg is questionable. Just change oil before it starts to decline like 10% before due.
Engine cleaning is mostly done by add pack not the base oil and they all seem to be nearly the same. It is all micro differences that one should be talking about and that should not make a difference such as 100k vs. 300k as some indicated.
Engine cleaning is mostly done by add pack not the base oil and they all seem to be nearly the same. It is all micro differences that one should be talking about and that should not make a difference such as 100k vs. 300k as some indicated.