Oil Specification priorities

Status
Not open for further replies.
Joined
Oct 12, 2015
Messages
325
Location
Illinois USA
When selecting an oil, I understand that the Manufacturers Approval is a primary consideration. I have 4 vehicles with 4 different approvals
smile.gif

But, I am wondering about the various specifications available at most manufacturers websites. I have made a few assumptions below.

In particular:
1. VI - larger number is better, right? Range is generally 160-190
2. Shear - Larger number better? Most are 3.x-4.x
3. NOACK - Smaller % is better?

Priority - How do you rank the following specs in importance between oils with correct approval:
TBN
VI
Shear
NOACK

Thanks.
Sorry if this is already out there. I searched with no luck.
 
Originally Posted By: IllinoisSparky
When selecting an oil, I understand that the Manufacturers Approval is a primary consideration. I have 4 vehicles with 4 different approvals
smile.gif

But, I am wondering about the various specifications available at most manufacturers websites. I have made a few assumptions below.

In particular:
1. VI - larger number is better, right? Range is generally 160-190

Not necessarily. For example, if high VI is achieved by having a ton of VIIs, then that's not good.

Quote:
2. Shear - Larger number better? Most are 3.x-4.x

High HT/HS viscosity is only better if your engine requires it. If it doesn't require it, then it just negatively impacts fuel economy.

Quote:
3. NOACK - Smaller % is better?

Yes.


Quote:
Priority - How do you rank the following specs in importance between oils with correct approval:
TBN
VI
Shear
NOACK

It really depends on the application. If I want to run a long OCI, then high TBN would be important. If I'm racing at the track, then possibly higher HT/HS viscosity would be rather important.

VI is just a calculated number based on 40C and 100C viscosity. VI isn't a part of any mfg spec requirement.
 
I think by "shear" you mean "high temperature/high shear (HTHS) viscosity." Probably best to clarify that, as "shear" is a process, not a spec.
 
Do you live someplace where pour point would be a consideration? And is API or ACEA Service Class a requirement as in keeping the warranty enforce?

For some these may not be at the top of the list but would be an absolute requirement when making a choice.
 
My limited education on oil leads me to the belief that you cannot compare and judge oils based on VOA data.

What some of the numbers tell you does not reflect the real world results. Lets examine TBN. Its assumed that a higher VOA TBN equates to a better oil. In reality, a lower starting TBN oil might be made of higher quality components. At the end of a 10,000 mile run, the better quality oil with initial lower TBN might end up with a higher TBN at the end of the OCI. Does that make sense?

Trying to determine oil quality by comparing VOA data is has limited value.*


* This is what the late (RIP) Stinky Peterson of CAT Oil Analysis tried to drum into my feeble brain many years ago. He emphasized that after doing thousands of UOA's, even he was unable to choose the silver bullet. An oil that was superb in Florida conditions might fail "noticebly" in Minnesota conditions. One might work excellent in a Ford and only average in a Chevy.
 
Originally Posted By: Quattro Pete


In particular:
1. VI - larger number is better, right? Range is generally 160-190

Not necessarily. For example, if high VI is achieved by having a ton of VIIs, then that's not good.



Is there any way to know if the VI is legit, or artificially achieved?

Thanks for all the other answers, QP.
 
To add to what Quattro Pete said: Specs need to be taken together and considered in context.

For example: If I see a high VI, high HTHS viscosity, and low NOACK together, that suggests a really high-end base oil. If I see a high VI with a low HTHS viscosity and high NOACK, maybe not.

Another example: TBN is nice, but it usually comes with a higher sulfated ash percentage. In my car, I'd rather have the lower ash value than the higher TBN; my car burns oil by design, and lower ash generally means less deposit formation. I can compensate for the lower TBN by just changing my oil more frequently. If I had a car that didn't burn much oil, I might go in the opposite direction.
 
Originally Posted By: d00df00d
Another example: TBN is nice, but it usually comes with a higher sulfated ash percentage. In my car, I'd rather have the lower ash value than the higher TBN; my car burns oil by design, and lower ash generally means less deposit formation.

Yup. Same if you have a modern diesel engine with DPF.
 
Originally Posted By: d00df00d
To add to what Quattro Pete said: Specs need to be taken together and considered in context.

For example: If I see a high VI, high HTHS viscosity, and low NOACK together, that suggests a really high-end base oil. If I see a high VI with a low HTHS viscosity and high NOACK, maybe not.

Another example: TBN is nice, but it usually comes with a higher sulfated ash percentage. In my car, I'd rather have the lower ash value than the higher TBN; my car burns oil by design, and lower ash generally means less deposit formation. I can compensate for the lower TBN by just changing my oil more frequently. If I had a car that didn't burn much oil, I might go in the opposite direction.


Thanks d00df00d. More excellent info. You and QP have given me the info I was looking for.
thumbsup2.gif

Bitog Derangement Syndrome has caused me to put all the oils for my various approvals into a spreadsheet to evaluate before purchases.
smile.gif
 
Originally Posted By: Quattro Pete
Originally Posted By: d00df00d
Another example: TBN is nice, but it usually comes with a higher sulfated ash percentage. In my car, I'd rather have the lower ash value than the higher TBN; my car burns oil by design, and lower ash generally means less deposit formation.

Yup. Same if you have a modern diesel engine with DPF.


And I do.
smile.gif

Requires MB229.51, updated to MB229.52
 
Originally Posted By: d00df00d
I think by "shear" you mean "high temperature/high shear (HTHS) viscosity." Probably best to clarify that, as "shear" is a process, not a spec.


Ooops.
blush.gif

Correct - referring to HTHS.
 
Originally Posted By: IllinoisSparky
Originally Posted By: d00df00d
To add to what Quattro Pete said: Specs need to be taken together and considered in context.

For example: If I see a high VI, high HTHS viscosity, and low NOACK together, that suggests a really high-end base oil. If I see a high VI with a low HTHS viscosity and high NOACK, maybe not.

Another example: TBN is nice, but it usually comes with a higher sulfated ash percentage. In my car, I'd rather have the lower ash value than the higher TBN; my car burns oil by design, and lower ash generally means less deposit formation. I can compensate for the lower TBN by just changing my oil more frequently. If I had a car that didn't burn much oil, I might go in the opposite direction.


Thanks d00df00d. More excellent info. You and QP have given me the info I was looking for.
thumbsup2.gif

Bitog Derangement Syndrome has caused me to put all the oils for my various approvals into a spreadsheet to evaluate before purchases.
smile.gif



Wow, so I'm NOT the only one to do that in a spreadsheet - Cool!
 
Originally Posted By: WhizkidTN
Originally Posted By: IllinoisSparky
Originally Posted By: d00df00d
To add to what Quattro Pete said: Specs need to be taken together and considered in context.

For example: If I see a high VI, high HTHS viscosity, and low NOACK together, that suggests a really high-end base oil. If I see a high VI with a low HTHS viscosity and high NOACK, maybe not.

Another example: TBN is nice, but it usually comes with a higher sulfated ash percentage. In my car, I'd rather have the lower ash value than the higher TBN; my car burns oil by design, and lower ash generally means less deposit formation. I can compensate for the lower TBN by just changing my oil more frequently. If I had a car that didn't burn much oil, I might go in the opposite direction.


Thanks d00df00d. More excellent info. You and QP have given me the info I was looking for.
thumbsup2.gif

Bitog Derangement Syndrome has caused me to put all the oils for my various approvals into a spreadsheet to evaluate before purchases.
smile.gif



Wow, so I'm NOT the only one to do that in a spreadsheet - Cool!


Yeah, I have used spreadsheets a couple of times for choosing oils.
Now with CK4 diesel oils, I may have another one coming up.
 
Originally Posted By: OneEyeJack
Do you live someplace where pour point would be a consideration? And is API or ACEA Service Class a requirement as in keeping the warranty enforce?

For some these may not be at the top of the list but would be an absolute requirement when making a choice.



The Ford sits outside in winter, but temps below zero are rare.
Only the 2011 still has a warranty, and I am paranoid enough that I use MB228.52 5W-30, or an oil on the Mercedes Bevo site to be safe.
thumbsup2.gif
 
HT/HS is good higher, until you creep into overkill. My R1 runs cool, 170s and 150's in the winter, so too thick isn't always great . Harley benefit from it though.
VI higher is not better if VII is used. Otherwise yes.
Noack is always better lower.
A lot of people scream yay high tbn, and drop 4 points after key turned with a Ca dominated add pack, and a 7 can outlast a 9 with Mg involved (just as an exaple).
I ignore everything about everyone and look at application. I run IS oil sticktly for noack, nothing else matters, no high loads, no cold weather, not a stressed engine...
HD gets Hths first, everything else later. Rx get free oil ;), and so on..
 
Last edited:
HT/HS Viscosity : Generally the higher the HTHS viscosity is better if you have an engine that runs hot, like aircooled motorcycles, or just about any high performance engine that gets driven hard, a lower HT/HS would be better for an engine designed for fuel economy, since a lower HTHS will mean slightly less internal drag from the oil.

A higher VI is better, but not if the oil is pumped full of viscosity index improvers.

With Noack volatility the lower the better, period.

TBN : The higher the better but some deplete faster than others, some oils have a starting TBN of as high as 12, but deplete quicker than others.
 
Thanks Dyusik and FCD.
More excellent, useful info.

All of the answers to my question have helped me to look at the specs slightly differently than before.
I used to think TBN was everything, because several of our vehicles are perfect examples of "severe duty"(cold weather starts, short trips, dusty conditions, etc.)
But, if the TBN is done using Calcium, it appears that the high number for those oils may not be as valuable as I thought.

Thanks again everyone.
 
Originally Posted By: IllinoisSparky
Thanks Dyusik and FCD.
More excellent, useful info.

All of the answers to my question have helped me to look at the specs slightly differently than before.
I used to think TBN was everything, because several of our vehicles are perfect examples of "severe duty"(cold weather starts, short trips, dusty conditions, etc.)
But, if the TBN is done using Calcium, it appears that the high number for those oils may not be as valuable as I thought.

Thanks again everyone.


For an oil that only has Ca-based detergents, high TBN is better. But when comparing to oils with a mix of Mg and Ca detergents, lower can be equivalent because Mg detergents help TBN retention.
 
Originally Posted By: A_Harman


For an oil that only has Ca-based detergents, high TBN is better. But when comparing to oils with a mix of Mg and Ca detergents, lower can be equivalent because Mg detergents help TBN retention.


More good info. Thanks A_Harman.

SO glad this thread didn't turn into a brand-vs-brand, "my oil is great and yours sucks" kind of discussion.
smile.gif

Actual, fact-based discussion is refreshing!
thumbsup2.gif
 
Status
Not open for further replies.
Back
Top