More important, ASTM test data or VOA's

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wemay

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Which one holds more water with you? I see some people swear by VOA's when chosing an oil, where I would think the ASTM is more conclusive in determining the quality of a product.
 
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Stick with the tests that actually provide certifications. VOAs give you some interesting things to compare, but not a lot more than that. Passing all the relevant tests is key to approval, whatever the approval happens to be. A pretty VOA has limited utility. It will give you some useful information if you're going for trended UOAs, mind you.
 
That's what I would think too. You just see so many people use the ingredients information to be the final determinant when their specs dont call for any special approvals.
 
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Well, it's kind of neat to see how much zinc is in a formula, how much moly there is, and what the starting TBN is, but those all have limited use. If we pick two conventional SN/GF-5 oils at random, we're going to have trouble determining the "better" of the two by any VOAs. At best, we'd be deluding ourselves.
 
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the "standard" tests have been designed to give a level of information that the industry accepts, even if it means modifying engines, and keeping them in store to provide those tests.

If a problem develops, they come out with another test engine/regime, and standardise that.

A UOA is a single dot on a chart...two of them is two, and you can draw a line...line is good data if it's your line.
 
The product data sheets provide performance information you can't get from any oil analysis, things like low temperature performance and HTHS.
UOAs provide data on how an oil holds up in service, which allows a user some guidance as to how long a given oil can be run in a given engine as it's typically used. This is information you can't get from the technical data provided by the blender.
Two different things and neither is the ultimate in itself in choosing an oil.
Bear in mind also that there are a number of non-mentallic adds that no blender will tell you about and no reasonably priced UOA will show.
 
Hey guy's, I'm referring more so about VOA, not UOA which are considerably more important in my estimation.
 
ASTM (and ACEA) would utilise elemental analysis and TBN, particle count etc. if they proved more reliable than tests....

would save them a fortune
would save oil makers a fortune
and there would be no need for "meets or exceeds" in any manufacturer's vocabulary.
 
I think VOAs are useful since there are always production variances, and because sometimes people want/need specific additives that aren't explicitly disclosed in a datasheet or tested by the various organizations.

That being said, if a VOA is not available for an oil I want to use, that doesn't stop me from using it if a reasonable datasheet is provided by the blender.
 
imo, uoa is simply useful as a gauge for contamination

the common aw compounds that show up are a nice bonus.

they will not tell you how well the oil lubricates
they will not tell you how well your engine is wearing, or the condition of it
sometimes, wear metal spikes can be an alert, and equally they can be false alarms. considering we've seen part failures that were not detected by uoa, and spikes in wear metals on engines that are fine.

so of course, the tests defined by ASTM
 
Originally Posted By: dparm
I think VOAs are useful since there are always production variances, and because sometimes people want/need specific additives that aren't explicitly disclosed in a datasheet or tested by the various organizations.

But, one VOA can be as wonky as product variances themselves. Nonetheless, for BP products, a VOA is pretty useful, given their lovely data sheets.
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VOAs are interesting because they show how much zinc, moly, calcium, boron, and titanium a formulator thought they needed to certify their oils meeting minimum performance standards such as SN or whatever they are going for. For example, it was always strange that German Castrol 0w-30 performed well yet had low levels of additives, meaning their base oil must have made up the difference we assume.
 
The more information and standards met the better.
Claiming to have met ASTM and API requirements is great but a VOA gives a good indication of quality control especially when compared to the companies own PDS info.
Consequently I rely more on VOA data (PQIA VOAs are the best)to uncover more of what I want to know about an oil.
 
Yes, but we do have to be cautious at times. We've seen some real outliers in the world of VOAs and UOAs. I love reading VOAs, particularly the PQIA VOAs, as much as the next guy. But, there are always going to be production variations.

There are examples in both directions. I'm guessing CATERHAM is referring to that Eneos mess with one of their 50 grades. We can also see things in the other direction, with PYB and QSGB having much lower Noack scores than published.

Of course, when it comes to many products the data sheets are poor or useless. Look at Formula Shell 5w-30 and Formula Shell Synthetic 5w-30. Either they are identical products or one or both data sheets is useless. I'm leaning towards the latter.
 
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