V.I. Revisited

[demarpaint]

Originally Posted By: jrustles
So after all is said and done, VI remains a dimensionless value as pointed out by Shannow a while back, and the value of each point is not close to being linear among various viscosities. Therefore, it seems to me, that the VI value as a solo spec has as much relevance to wear protection as a UOA does to engine condition. 200+VI Automatic Transmission fluid (for various reasons) will not better protect an engine vs dino 5w20 during a -25C cold start. I can't prove that, but I'd pay upwards of 3 bucks for someone to make that case.


I think after its all said and done there's a lot more to a good oil than just its VI.

 

[martinq]

Originally Posted By: jrustles
... but I'd pay upwards of 3 bucks for someone to make that case.

A challenge?!

 

[cp3]

I see plenty of opinion presented as fact here everyday, not jut by "a guy from the internet who has an oil gauge" and many of them (most) are not backed with proof. For many topics here there is no proof. Where would one find proof that brand X is better or worse than brand Z? Does it exist? The discussions continue yet I don't recall seeing proof.

Is it safe then Pete, to assume that you have never strayed from your vehicle manufacturers recommendations? Or have there times when you too have been in conflict with "those who are actually educated, trained, and experienced in determining proper oil specifications for a given application"?

If you take Caterham's theory to mean "pour in anything you want, as long as pressure and temperature are good" then you don't really understand it. I never took his ideas to mean pour anything in as long as it's high VI and pressure and temp are good. The two oils I used both stand well on their own, in my opinion and should provide adequate wear protection if used in suitable conditions and engines. Combining them to tailor viscosity just doesn't seem like a stretch to me. If you don't agree, all the power to you, I have no problem with that.

 

[cp3]

Originally Posted By: HangFire
Originally Posted By: cp3
So then what's the point of BITOG?


I can answer that!

The point of BITOG is to reinforce my OCD behaviors, justify my predilictions, keep me off other forums and make me sound intelligent in front of my non-amateur-tribologist friends.

Originally Posted By: cp3
Maybe it should just be closed down and a page posted to follow OEM recommendations?


I certainly hope not. I need BITOG. Every time I bring up the finer points of oil brand and type selection on other forums, a whole bunch of guys pile on with "just pick a brand name in the mfg recommended weight", drown me out and then consider it the end of the discussion and lock the thread. (Except for the inevitable magic pixel fairey dust oil salesman who is pushing his brand as superior to all the rest.) What a boring bunch they are.

HF


We're here for ya man!

 

[cp3]

Originally Posted By: demarpaint
Originally Posted By: jrustles
So after all is said and done, VI remains a dimensionless value as pointed out by Shannow a while back, and the value of each point is not close to being linear among various viscosities. Therefore, it seems to me, that the VI value as a solo spec has as much relevance to wear protection as a UOA does to engine condition. 200+VI Automatic Transmission fluid (for various reasons) will not better protect an engine vs dino 5w20 during a -25C cold start. I can't prove that, but I'd pay upwards of 3 bucks for someone to make that case.


I think after its all said and done there's a lot more to a good oil than just its VI.


I agree. That said I just don't believe there is a whole lot of difference between good/better/best SN oils when it comes to protection. After all, isn't that the idea of API? So where do you go to play after that if it isn't viscosity?

 

[jrustles]

Originally Posted By: demarpaint
Originally Posted By: jrustles
So after all is said and done, VI remains a dimensionless value as pointed out by Shannow a while back, and the value of each point is not close to being linear among various viscosities. Therefore, it seems to me, that the VI value as a solo spec has as much relevance to wear protection as a UOA does to engine condition. 200+VI Automatic Transmission fluid (for various reasons) will not better protect an engine vs dino 5w20 during a -25C cold start. I can't prove that, but I'd pay upwards of 3 bucks for someone to make that case.


I think after its all said and done there's a lot more to a good oil than just its VI.


Absolutely.

Selecting an oil based on a property for use in an application where it's not specifically demanded, just for the sake of knowing it has a wider spread, is nonsensical to me. Yes, VI polymers are stronger and optimized for NOT stability but they're not magical. Chemically VI cannot be obtained without sacrificing some other property of the oils equilibrium, from NOACK to production cost. There is no free lunch, so at least know your risks; ie more volatility, more varnishing potential, less stability at high temperatures or just simply higher cost.

 

[buster]

Originally Posted By: jrustles
Originally Posted By: demarpaint
Originally Posted By: jrustles
So after all is said and done, VI remains a dimensionless value as pointed out by Shannow a while back, and the value of each point is not close to being linear among various viscosities. Therefore, it seems to me, that the VI value as a solo spec has as much relevance to wear protection as a UOA does to engine condition. 200+VI Automatic Transmission fluid (for various reasons) will not better protect an engine vs dino 5w20 during a -25C cold start. I can't prove that, but I'd pay upwards of 3 bucks for someone to make that case.


I think after its all said and done there's a lot more to a good oil than just its VI.


Absolutely.

Selecting an oil based on a property for use in an application where it's not specifically demanded, just for the sake of knowing it has a wider spread, is nonsensical to me. Yes, VI polymers are stronger and optimized for NOT stability but they're not magical. Chemically VI cannot be obtained without sacrificing some other property of the oils equilibrium, from NOACK to production cost. There is no free lunch, so at least know your risks; ie more volatility, more varnishing potential, less stability at high temperatures or just simply higher cost.


Exactly.

 

[Solarent]

Originally Posted By: jrustles
Selecting an oil based on a property for use in an application where it's not specifically demanded, just for the sake of knowing it has a wider spread, is nonsensical to me. Yes, VI polymers are stronger and optimized for NOT stability but they're not magical. Chemically VI cannot be obtained without sacrificing some other property of the oils equilibrium, from NOACK to production cost. There is no free lunch, so at least know your risks; ie more volatility, more varnishing potential, less stability at high temperatures or just simply higher cost.


I agree, the whole idea of matching the engine/oil/conditions is a series of weighing out the pros and cons of each property. So depending on your priorities and what you value, your conclusions will be uniquely your own.

Originally Posted By: Solarent
So why is VI the holy grail of oil specification: Matching the right viscosity properties of an oil to your engine is one of the important considerations in selecting the best oil for your vehicle. It will continue to be very important when the next round of oil specifications are completed, as new engines will be designed for thinner oils, and the new thinner oils (starting in 2016) may not work for many older engines. As far as comparing the viscosity performance of two oils goes, the VI is king - as long as you remember that the VI comes from a combination of baseoil selection and additive formulation.

Why is the VI not the holy grail? there is much more to an oil's performance in an engine than just the viscosity performance. But most of the information you need to compare additive package performance isn't available on your typical specification sheet, mostly because there aren't bench tests that can be used to accurately quantify that information. So through some experimentation and work on your own vehicle (if you care and have the time to do so), you can find a great oil/vehicle combination that suits your needs, and it may not necessarily need to be the one with the highest VI.


Like I said originally - both sides are right, depending on what oil attribute better suits your situation or what you value more.

 

[CATERHAM]

Originally Posted By: martinq
Originally Posted By: jrustles
... but I'd pay upwards of 3 bucks for someone to make that case.

A challenge?!

There is no case to be made.
Stating that VI "remains a dimensionless value" while true is an obfuscation of the issue.
As Garak has pointed out a few times, the trend to higher and higher VIs in motor and transmissions oils is indisputable. That's why we all run multi-grade oils and even the most ardent critics of high VI oils aren't suggesting running 80-100 VI single grade dinos any longer although they did 40-50 years ago.

The advantages of stable VIs as high as possible are very compelling. For a given hot normal operational viscosity, a higher VI oil will be both lighter on start-up while providing greater high temp' protection (a higher HTHSV).
What's not to like about that?

If the critics of high VI oils were more honest there main problem is that their favourite oil or oil brand doesn't have a particularly high VI and that's why you'll get defensive remarks like "there is more to a good oil that just it's VI".
Of course there is. VI is just a characteristic of an oil's viscosity. It's just that viscosity is the most important attribute of an oil.

 

[demarpaint]

Originally Posted By: CATERHAM

If the critics of high VI oils were more honest there main problem is that their favourite oil or oil brand doesn't have a particularly high VI and that's why you'll get defensive remarks like "there is more to a good oil that just it's VI".


That's not a defensive remark its a fact.

 

[CATERHAM]

Originally Posted By: demarpaint
Originally Posted By: CATERHAM

If the critics of high VI oils were more honest there main problem is that their favourite oil or oil brand doesn't have a particularly high VI and that's why you'll get defensive remarks like "there is more to a good oil that just it's VI".


That's not a defensive remark its a fact.

LOL!
Yes and it's still a defensive comment.
Name one low VI oil you think is great and I'll tell why it's not.

 

[demarpaint]

Originally Posted By: CATERHAM
Originally Posted By: demarpaint
Originally Posted By: CATERHAM

If the critics of high VI oils were more honest there main problem is that their favourite oil or oil brand doesn't have a particularly high VI and that's why you'll get defensive remarks like "there is more to a good oil that just it's VI".


That's not a defensive remark its a fact.

LOL!
Yes and it's still a defensive comment.
Name one low VI oil you think is great and I'll tell why it's not.


LOL I read your threads, no point in wasting your time or server bandwidth. If the VI is under 200 the oil is no good in your book, around 220 VI is liquid gold.

 

[Trav]

While i think there is more to oil than just one important property i don't know enough about it to comment.
I will say that in all honesty Caterham has provided some good info that for many years went against the grain of everything i had been told or read and it made me a little testy to say the least.

In all fairness some of the suggestions have really helped me make better choices in certain situations IMO and i will keep an open mind.
I don't think VI is the only value to consider in making a decision but there does seem to be something to a higher VI that makes good oils even better.

No i haven't gone of my rocker, i am definitely old school but everything in this business is evolutionary including oils and lubricants.
I accept the basic premise that if the engine can maintain suitable oil pressure then the lightest oil will have less drag and provide some benefits, if higher VI help keep the oil in grade then i don't think its a bad thing.
My only question is how high is high enough before it becomes just a high number.

 

[Shannow]

Originally Posted By: CATERHAM
Originally Posted By: martinq
Originally Posted By: jrustles
... but I'd pay upwards of 3 bucks for someone to make that case.

A challenge?!

There is no case to be made.
Stating that VI "remains a dimensionless value" while true is an obfuscation of the issue.


CATERHAM, it IS a diensionless number, and your defence of the uber sheared M1 0W-40 because it "retained a high VI" shows that you place more value on the VI parameter than the actual parameter that protects stuff...the viscosity.

I have asked repeatedly, including in my dimensionless number thread for you to quote some (any) engineering text that starts with VI in any design...they don't...in either hemisphere.

I have stated repeatedly that VI makes an oil's viscosity "less wrong" at temperatures off design, which is a good thing, as long as the actual viscosity of the oil remains as designed in service.

 

[martinq]

Originally Posted By: Trav
My only question is how high is high enough before it becomes just a high number.

I think a VI in the 500+ range would be close enough to ideal as to not worry about it anymore. The fluid would be close enough to 'perfect' as it approaches 1000.

To my understanding there is no value that is high enough.

 

[Shannow]

Originally Posted By: demarpaint
Originally Posted By: CATERHAM

If the critics of high VI oils were more honest there main problem is that their favourite oil or oil brand doesn't have a particularly high VI and that's why you'll get defensive remarks like "there is more to a good oil that just it's VI".


That's not a defensive remark its a fact.


LOL, find my "favourite" oil in any of my psots...it changes.

My least favourite oils in my professional career are those that lose 30-50% of their viscosity within weeks of being placed in the compartment, making reliability a serious issue.

 

[Shannow]

Originally Posted By: demarpaint
Originally Posted By: CATERHAM

If the critics of high VI oils were more honest there main problem is that their favourite oil or oil brand doesn't have a particularly high VI and that's why you'll get defensive remarks like "there is more to a good oil that just it's VI".


That's not a defensive remark its a fact.


Ford seemed to think that a bajillion miles of testing meant that their 5W-20 was good enough to be "favourite"...and CATERHAM has recommended NOT to run TGMO in those engines previously...

Ferrari are happy with their favorite 5W-40.

 

[Shannow]

Originally Posted By: CATERHAM

Of course there is. VI is just a characteristic of an oil's viscosity. It's just that viscosity is the most important attribute of an oil.


In hydrodynamic lubrication, most certainly...but as per the xW-16 papers, they (engine manufacturers) are pushing through hydrodynamic and into mixed/boundary lubrication during normal engine operation.

That's where the surface active additives will protect you when viscosity is not enough. And if they don't it's game over right now.

 

[Solarent]

Originally Posted By: Shannow
In hydrodynamic lubrication, most certainly...but as per the xW-16 papers, they (engine manufacturers) are pushing through hydrodynamic and into mixed/boundary lubrication during normal engine operation.

That's where the surface active additives will protect you when viscosity is not enough. And if they don't it's game over right now.


Yes, everything is pointing to relying more and more on the surface additives and bearing materials to protect in the mixed/boundary regimes. This is also one of the reasons that the deadline for these oils is being pushed back again, because the testing and balance between ultra low viscosity and surface additives is proving difficult - especially in domestic vehicles.

BUT let's not forget that one of the main reasons why these low viscosity oils are even being considered is because of the developments in high viscosity index base oils and advanced shear stable polymers. You can't have one without the other.

However, I would also dispute that viscosity is the most important characteristic of oil - I think the remainder of what goes in the oil and how the oil is protecting in all lubrication regimes (boundary, mixed, hydrodynamic and elastohydrodynamic) is equally as important.

 

[cp3]

Originally Posted By: Trav
While i think there is more to oil than just one important property i don't know enough about it to comment.
I will say that in all honesty Caterham has provided some good info that for many years went against the grain of everything i had been told or read and it made me a little testy to say the least.

In all fairness some of the suggestions have really helped me make better choices in certain situations IMO and i will keep an open mind.
I don't think VI is the only value to consider in making a decision but there does seem to be something to a higher VI that makes good oils even better.

No i haven't gone of my rocker, i am definitely old school but everything in this business is evolutionary including oils and lubricants.
I accept the basic premise that if the engine can maintain suitable oil pressure then the lightest oil will have less drag and provide some benefits, if higher VI help keep the oil in grade then i don't think its a bad thing.
My only question is how high is high enough before it becomes just a high number.

....sorry Trav, I couldn't resist! Welcome to the dark side...sort of....let's call it grey where you are...lol