I've noticed a tendency for the synthetics with the lowest NOACK to post higher TEOST Deposit numbers and vice versa.
Can someone explain the likely reasons why?
Can someone explain the likely reasons why?
NOACK vs TEOST
- Thread starter Gene K
- Start date
Amsoil SS 5W30 don’t follow that trend
MrQuackers
Site Donor 2024
Noack volatility test - Wikipedia
Yes I know Amsoil Signature doesn't follow that trend. My simple (although obviously flawed) reasoning would think an oil with more evaporation would leave more deposits but in most cases it seems to be the reverse.
I'm asking why? The only theory I have is that possibly the same oils that have lower NOACK also have higher additive rates so more is left behind when they do evaporate (Which doesn't explain outliers like Signature that we know has a significant additive package).
I'm asking why? The only theory I have is that possibly the same oils that have lower NOACK also have higher additive rates so more is left behind when they do evaporate (Which doesn't explain outliers like Signature that we know has a significant additive package).
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I think your answer lies in the presence of esters or lack thereof.
"Heavier" oils are less volatile, but are more prone to leaving more carbon residues and don't solubalize carbon as well as "lighter" oils.
"Lighter" oils are more volatile, and help solubalize carbon deposits as they form and also contribute less to deposit formation.
Just typical trade-offs when selecting base oils.
"Lighter" oils are more volatile, and help solubalize carbon deposits as they form and also contribute less to deposit formation.
Just typical trade-offs when selecting base oils.
The polar character of esters also makes them good solvents and dispersants. This allows the esters to solubilise and disperse impurities such as combustion residues and oil degradation, by-products that might otherwise dispose as sludge or varnish deposits. These properties result into cleaner operation and improved additive solubility in the final lubricant. Cleaner engine or transmission systems will be the consequence.
Thank you. That is the kind of thought I was looking for. I knew the basic info but hadn't made the connection that it's possible for a darker side of Low NOACK to exist.
This answer was better.
How did you notice these tendencies and what does higher deposit number mean? is the delta deposit significant or just a mathematically higher number but insignificant?
Is there a paper or a study showing how different oils performed?
Not trying to argue but am interested in more details mainly because I chase low Noack oil.
Just something I've noticed in various different comparisons. Yes some are biased like Amsoil sponsored one and others don't give the brands just a number like the AAA conventional vs synthetic comparison but it seems to be a reoccurring trend.
It would stand to reason that given similar class of bases such as Group III/III+ with the higher viscosity base and lower viscosity base reversed could drive NOACK and TEOST in opposite directions.
It would stand to reason that given similar class of bases such as Group III/III+ with the higher viscosity base and lower viscosity base reversed could drive NOACK and TEOST in opposite directions.
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Not separating the two very different TEOSTs the explanations must become all too empireic, wouldn't they? The hot rod & atmosphere variety might see an ester oil as worse (or as better than properly illustrating combustion chamber fate), the wetter variety discriminate between VM enough to be hard to relate to NOACK of lighter and heavier base components... I don't think one or two short answers will show the way here. Each TEOST would have so many more problems than just its temperature, the triangle won't work out to really reflect anything.
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In in-house high temperature, thin film deposit tests that my former company ran regularly, PAO and Group III based oils always left more deposits than Group I or ester based oils. The lack of polarity/solubility of these higher group hydrocarbon base stocks meant they were not able to solubilize or disperse oxidation by-products that lead to deposits. Pure ester based oils were always the cleanest by far, and had the lowest Noacks by far.
That said, our test oils were industrial and aviation products that did not contain detergents or dispersants, which can influence such tests, and we never attempted to establish any correlation between our test and the TEOST test. The solubility principle, however, may still apply.
That said, our test oils were industrial and aviation products that did not contain detergents or dispersants, which can influence such tests, and we never attempted to establish any correlation between our test and the TEOST test. The solubility principle, however, may still apply.
Like I said, I think your answer lies in the presence of esters or lack thereof. I just gave the short version.
Had these tests been run at common temperatures around the 275-300°C? One of the remaining questions (if looking beyond 33c and MHT) would be, how far their window of nasty behaviour may have shifted ;-) Depending on application or exact focus it wouldn't necessarily mean much difference around the rings or via premix, metering oil pump or else.
Ketjenlube polymer esters once had been presented as if they were first to be allowable right into combustion chambers and Croda of 21st century depicted some POE as admirable while Idemitsu heading for some Le Mans of 20th century still avoided them – because of engine tests of course, but also over accompanying thin film coker testing.
Croda ran the coker tests at 275°C, Idemitsu at 280°C – so much transparency's already in it. TEOST 33c specifically aiming at turbo shafts has more heat but no air. So, please don't hesitate to give any longer versions. Despite not much ester content to be expected in most of the oils around, if I don't get Gene K totally wrong.
Ketjenlube polymer esters once had been presented as if they were first to be allowable right into combustion chambers and Croda of 21st century depicted some POE as admirable while Idemitsu heading for some Le Mans of 20th century still avoided them – because of engine tests of course, but also over accompanying thin film coker testing.
Croda ran the coker tests at 275°C, Idemitsu at 280°C – so much transparency's already in it. TEOST 33c specifically aiming at turbo shafts has more heat but no air. So, please don't hesitate to give any longer versions. Despite not much ester content to be expected in most of the oils around, if I don't get Gene K totally wrong.
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Is polybutene a base stock for any engine oil or is it an avionics oil?
I did a quick search and seems like polybutene is used in VII, DI pkg and also in fuel. Is that correct?
also polyolester base results seems to be off the chart (residue graph) in this study. Is that right?
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