Do modern VII's deplete in oil at a linear rate ?

[ChrisD46]

As the question states - do VII's in modern oil formulations deplete at a linear rate ? My reason for asking has to do with potentially controling deposits and if my OCI schedule could reduce the amount of VII induced deposits I may potentially ecounter ? The affect of depleted VII's in oil as related to deposits would of course be closely tied to this question . My actual comparison interest is between M1 5W30 and M1 10W30 . *The background on this line of questioning has to do with research indicating a potential link between oil with higher VII's and intake valve deposits in GDI engines . Your thoughts and experiences ?

 

[FCD]

The Polymers that VIIs are made from have certainly improved, and more stringent standards have forced oil companies to forumlate their oils with less VIIs, and better ones.
Definetly a modern 10W-40 Conventional oil ( an example of an oil that requires a fair bit of VIIs ) will stand up to heat MUCH better, than a 10W-40 Conventional oil from 40 years ago.

 

[MolaKule]

What research?

VII's are typically hi molecular weight polymers that contribute little to ash formation.

VII's don't "deplete" as much as they shear, but modern VII's are more shear resistant and tend to "heal" after shearing.

 

[ChrisD46]

Thanks for replies - trying to get my head around how VII's (sheared or otherwise) may contribute to intake valve deposits ?

 

[merconvvv]

I think i read on amsoil site that changing your oil too much causes deposits because new oil is more volatile.
So volitility is function of usage? Can someone explain? If after 1000 miles some good stuff has burned off then why add them in the first place?

 

[merconvvv]

Vii dont deplete as much as they shear but they do deplete and how much is the real question for a given oil?