Maybe fuel evaporated from the sample over time. More air volume in the depleted sample container allowing fuel to evaporate?If it’s the same bottle of oil, how can viscosity go up during a retest?
It went from looking poor to looking decent all the sudden. So which report shows the ACTUAL condition of the oil, we’ll never know at this point.
Mobil 1 5W/30 EP HM, 4863 miles, 1996 Acura 3.5 RL. 3 Labs
- Thread starter DuckRyder
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OAI said they got my message and will respond in 48 hours.
OK so clearly Blackstone did in fact test the correct sample both times, as the spectral analysis is virtually identical between test #1 and #2.
The big difference between their 2 tests is the viscosity, moving from 8.98 to 9.97. In the comments, Blackstone calls this "normal variation." Really?
This reaffirms my view that the UOA tests are too inaccurate to be taken seriously. Can't wait to see OAI's retest results.
The big difference between their 2 tests is the viscosity, moving from 8.98 to 9.97. In the comments, Blackstone calls this "normal variation." Really?
This reaffirms my view that the UOA tests are too inaccurate to be taken seriously. Can't wait to see OAI's retest results.
Wow. Just opened the two OAI results side by side. Fluid properties like viscosity remained unchanged but the spectral analysis results aren't even close. The OAI re-run results are much closer to Blackstone, though. So either OAI did in fact mix up the samples on the 1st run or they're picking numbers from a hat!
Did they try to explain why their 2 reports are so wildly different?
Did they try to explain why their 2 reports are so wildly different?
OVERKILL
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Interesting, so Flashpoint went up, considerably, to 395F, this makes the OAI 1.3 % fuel number more reasonable. Viscosity changed massively as well.
Here is Blackstone re-reun.
Crickets from OAI so far.
OVERKILL
$100 Site Donor 2021
OK, so the metals all changed massively, so I'd assume it was not the same sample run in that test the first time (it got mixed up). The rest of the report didn't change, so I assume that means the other tests were all run on the correct sample, or they didn't re-run them.
Now it's the NAPA sample that the metals don't align on, as OAI and Blackstone are at least pretty close on those, lol.
This is yet another reason why picking "winners" via UOA's is such a futile endeavour. Take yesterday's lovely exchange in the now locked thread where fuel dilution was being ignored and an oil being blasted for fallout out of grade, yet the variance just between these two Blackstone reports is bigger than what would have put that oil in grade and they (Blackstone) are describing this as "normal" variation?
Many put FAR to much stock/confidence in what inexpensive spectrographic analysis tells us, as well as ascribing a level of accuracy to the results that, clearly, based on the words of Blackstone, simply isn't there.
Ive made little secret that I consider this basically a hobby / data. Ive long since established that 5000-7500 is no problem on any vehicle i own for the oil i use. This particular one uses/leaks a little so 5000ish just makes it easy...
What stock i put in them i put in the trending from blackstone. I occasionally send a sample somewhere else and thought id try OAI since many seem to trust them a lot. Ive sent the same samples to ALS and to BlackStone before and they are typically pretty close, so this is interesting / puzzling.
The next one up will be the Escape, so we will send that one off to all 3 and see what happens...
What stock i put in them i put in the trending from blackstone. I occasionally send a sample somewhere else and thought id try OAI since many seem to trust them a lot. Ive sent the same samples to ALS and to BlackStone before and they are typically pretty close, so this is interesting / puzzling.
The next one up will be the Escape, so we will send that one off to all 3 and see what happens...
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This is why I don't have any desire to do UOA. Different results from the same oil,yeah not rock solid information for this guy to waste money on.
Well every Lab is using different equipment and although they may be calibrated using the same standard, obviously some variation in the data is to be expected.
Of course I’m talking about 1-3ppm here, which will be the case even if the same Lab reruns the exact same oil twice. That’s normal.
Now, if one Labs report 10ppm of iron and the other one shows 30!!! I’d gladly cast my vote for there being no accuracy in UOA results but that isn’t the case, most of the time.
Differences in Viscosity measurement is puzzling though…
and if they can’t all agree on whether the oil has fallen out of spec or not then that’s just sad. I would think these lab's primary customers, which I assume are fleet/industry, would see big inconsistencies like these in their many reports. If the labs were this inconsistent/inaccurate regularly, you would think the firms would call foul, and the labs would improve, and have a method by now that is largely refined to eliminate big errors. I just don't see this happening regularly or even semi-regularly, and most definitely not enough for people like us to be concerned with.
Same sample:
Same sample:
OVERKILL
$100 Site Donor 2021
Yup. And that aptly demonstrates how out to lunch Blackstone is on fuel.
So you’ve never heard of a thing called an accuracy range? I’ll use non-contact temperature measurements in my industry. Even the very best handheld devices that do not touch the surface of the item being measured are +/- 2%. At 100*F, that’s a window of 4*. At the 2700*F temps we see in process, that equates to +/- 54*, or a window of 108*! So is the measurement 2650, or is it 2750? Yes! According to that piece of equipment.If it’s the same bottle of oil, how can viscosity go up during a retest?
It went from looking poor to looking decent all the sudden. So which report shows the ACTUAL condition of the oil, we’ll never know at this point.
The devices we use to touch the process are accurate to 0.1%, meaning there is a window of 5.4* TOTAL. However, the device that is 0.1% accurate costs roughly 35 times as much as the one that’s 2%….
And you want all this data from your oil for $35 but yet you want to complain about a possible range of completely acceptable testing variation?? C’mon, man!
