[JoeFromPA]

Thanks JFP. To be blunt but not to be insulting, when you were stating you had an extensive collection of UOAs but weren't linking to it, I was starting to wonder what I was missing out on. Now I understand, and respect that.

Below is my take on UOA as a tool for analyzing oil effectiveness, read or ignore as you wish as its my own opinion:

Here's a few things I've learned from about 4 years of amateur oil analysis for myself and many others: UOAs are almost meaningless, in terms of wear metals. Countless hours of discussion go into iron PPM, or lead, or copper. But it comes down to wear metals being meaningless. Wear metals in a UOA are a reflection of a narrow range of dissolved metal particle size, and can be influenced by a single particle streak off one bearing that's an isolated event.

Things I think are important but reflective of car condition are typically Silicon, Potassium, and Sodium. I don't care about UOA-based analysis of additive package...for example, levels of zinc and phosphorous in UOAs are almost meaningless outside of specific engine designs (such as flat tappet). Great if someone added boron suddenly, but at the end of the day the UOA doesn't actually tell you whether or not the additive package is superior or inferior.

...

In terms of analyzing oil effectiveness, I care about the following:
TBN and/or TAN content at a given mileage & time of use (vs. virgin if possible, though not critical)

Viscosity at a given mileage & time of use

Insoluble level (for filtration analysis)

- That's it for me. Anything else is almost completely useless for interpretation.

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So, if you are willing to share, I'd ask this: do you have at least 3+ 986 UOAs that used an oil for 7000-8500 miles within a period of 9 months, were regularly driven and had no track time, and that sheared the following:

M1 0w40 down to a 20 grade
M1 15w50 down to a 30 grade

or some other combination that dropped 2 grades, and at the same time had a fuel content of 2% or less?

I understand about heat - what's the typical driving temp of the boxster? Almost all modern synths can withstand 240-250 all day long without degradation, for 7.5k miles or longer. However, I understand your point about spot heat....impossible to know it's true effect in the abstract.

Thanks for all your time