Please list your top 4 spec catagories

[ProfPS]

I have noticed that everyone is in agreement that all SM rated oils are good for typical OCI's of 4-5k miles. I used to hold the Visocity Index spec in high regard when comparing oils of the same grade as that this is an indicator of how well it holds its viscosity over the tested temp range. After following oil spec data for over 10 years, reading everyone's posts, and reviewing posted used oil analysis, I no longer see it as a key indicator when comparing oil. Since the SM rating has been in effect, many 5w30 oils that had SL visc. index's of 160 are now in the low 150's while continuing to be highly recommended by BITOGers and producing very good used oil analysis.

Given the list of standard oil spec tests, what are your top 4 prioritized specs (cSt @40, cSt@100, HT/HS, pour pt, flash pt, etc.) when comparing oil of the same grade? I know that printed oil specs do not represent every drop of produced oil due to production variations, but it is an indicator.

Thx.

 

[JAG]

I have to expand the choices because my VW 1.8T engine's needs go way beyond spec sheet data in order to address keeping the engine clean.

1. High oxidative and thermal stability
2. High detergency/dispersancy
3. Low or medium volatility
4. Desired Viscometrics as indicated by HTHS, cst@100C and 40C.

The climate here is not that cold in the winter so the XW category is not very relevent to me, especially since my categories 1-3 require synthetic anyway.

 

[buster]

What JAG said.

 

[Pablo]

I have yet to see a lube that wasn't a compromise in one spec area, or price, or formulation. When we see good specification numbers on paper, it's a good indicator, but not the be all, end all of how well a lubricant will do in real life. You may formulate a great oxidation resistant lube, with terrible wear prevention, or it may cost $15/qt. I guess what I'm saying is that some of these tests may be fooled....to get great lab results, but not be a good oil for all applications.

One test that bugs me is HT/HS. Seems like this can be fooled by some VII's....or rather, why is it that some relatively high HT/HS oils are not the best oils? Pour point too. VI can also be fooled.

 

[buster]

Originally Posted By: Pablo
I have yet to see a lube that wasn't a compromise in one spec area, or price, or formulation. When we see good specification numbers on paper, it's a good indicator, but not the be all, end all of how well a lubricant will do in real life. You may formulate a great oxidation resistant lube, with terrible wear prevention, or it may cost $15/qt. I guess what I'm saying is that some of these tests may be fooled....to get great lab results, but not be a good oil for all applications.

One test that bugs me is HT/HS. Seems like this can be fooled by some VII's....or rather, why is it that some relatively high HT/HS oils are not the best oils? Pour point too. VI can also be fooled.


Completely agree with you here.

 

[TallPaul]

HT/HS
NOACK
ZINC
100C viscosity

Not necessarily in that order. I would love it if they included a spec for base oil viscosity.

I don't pay any attention to viscosity index because you never know what part of the number is from the base oil, vs what part if from VIIs. So to me, it's a useless number.