mixing oils can eat your engine?

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Originally Posted By: OVERKILL
Certainly. But they are speaking of the natural VI's of the base oils, not that they are filling their synthetic offerings full of polymer
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Schwing!
 
So the benefit will only accrue from the part of the VI that is provided by the base oil? Any VI increase that comes from polymer has no benefit?

If there was no benefit, why would they boost the VI?

But really, I don't really understand the point you're driving towards.

I think it's notable that Mobil see fit to increase their VI further than the base oil alone. They did this even before the modifier was as shear stable as it is now. And this oil is chosen by AMG and also by Nissan for the GTR.

Again, even when they didn't have as stable a modifier, Mobil, AMG, Nissan, favored the oil with the highest VI.
 
Originally Posted By: surfstar
Originally Posted By: S65AMG
If there's no harm in mixing oils, which must be particularly true when the oil is essentially identical except for the amount of VIIs, and if there is a benefit in getting improved viscosity performance, then wouldn't the benefit of mixing outweigh the perceived risks?


If your engine needs a specific viscosity, you can probably find the exact one you want in a particular oil, as blended off-the-shelf.

Someone who adds a quart of Redline to a 80% Grp II dino sump, is not likely to achieve the performance benefits of either. This "synthetic blend" would likely be better achieved by running one that was formulated as a blend from the beginning.




No harm - but what benefit?

VIIs are not the holy grail of performance specs either. I prefer a shear-resistant 10w30 (preferential to my climate).

This, as many posting on BITOG, is my opinion. I do not have data to backup the claim for or against backyard blending. I just believe that triboligists, that do this for a living, are better at it than I.



I was going to stay out of this thread. But I do remember a Havoline/Redline UOA that was on the old oildrop server that seemed not to make the migration in this exact ratio and it was a exceptional UOA. The poster wanted to have better start up protection and he figured since the additive packages where more similar than different this would be the best blend. This was in the SL days when Havoline had a boatload of moly compared to today.

A very good blend can be achieved and bad ones could be done too. Tallpaul's franken brews come to mind but his engines thrived after bad blends. IMO this thread has gone on far too long because if we are blending API certified oils no harm no foul.
 
Originally Posted By: S65AMG
So the benefit will only accrue from the part of the VI that is provided by the base oil? Any VI increase that comes from polymer has no benefit?

If there was no benefit, why would they boost the VI?

But really, I don't really understand the point you're driving towards.

I think it's notable that Mobil see fit to increase their VI further than the base oil alone. They did this even before the modifier was as shear stable as it is now. And this oil is chosen by AMG and also by Nissan for the GTR.

Again, even when they didn't have as stable a modifier, Mobil, AMG, Nissan, favored the oil with the highest VI.


The reason for the certifications from the manufactures is about money and that benefits both parties involved.
 
Originally Posted By: S65AMG
So the benefit will only accrue from the part of the VI that is provided by the base oil? Any VI increase that comes from polymer has no benefit?


Do you understand the difference between the natural VI of the base oil and the function of a polymer VII? If not, we might as well end this discussion now.

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If there was no benefit, why would they boost the VI?


They boost the VI/add VII so that the oil can be called 0w-40. It likely isn't one without them. Simple enough answer for you?

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But really, I don't really understand the point you're driving towards.


Don't worry, I don't understand yours either.
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I think it's notable that Mobil see fit to increase their VI further than the base oil alone. They did this even before the modifier was as shear stable as it is now. And this oil is chosen by AMG and also by Nissan for the GTR.


Do you know what M1 0w-40 would be without any VII's? No? Neither do I. But I'm betting it wouldn't be a 0w-40. You appear to have a fundamental misunderstanding of the role of VII's in the formulation of lubricants. They are used to tailor the viscosity of the finished product so that it can be called a 5w30, 0w-40....etc. They aren't just used to boost the VI to some magic number somebody dreamed up. The VI isn't necessarily the goal of the formulators, it is a byproduct (intentional I'm sure) of the base stocks used and the amount and type of polymer blended into the lubricant to achieve a given viscosity curve.

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Again, even when they didn't have as stable a modifier, Mobil, AMG, Nissan, favored the oil with the highest VI.


No, they favoured the oil from the formulator that they had the OEM relationship with and that met all the performance characteristics they desired. Pennzoil Ultra Euro 5w-40 has an almost identical list of certs and approvals and certainly doesn't have anywhere near the same VI. Yet Ferrari appears to have no problem with its "lacklustre" VI
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You are focusing on a single characteristic and giving it far more weight than it deserves. It is the PERFORMANCE of the finished product that is important. And while the VI of the lubricant certainly has a role in that performance, there are many other contributors, many of which, like the base oils used, who's roles are much more important. You can have a high VI polymer cocktail with some mediocre base stocks and a poo poo additive package that would lead to gummed up rings, varnish, coking, sludge, excessive wear....etc. A VI of 240 isn't going to fix a poorly blended product with horrendous oxidation and anti-wear performance.
 
Originally Posted By: OVERKILL
It is the PERFORMANCE of the finished product that is important. And while the VI of the lubricant certainly has a role in that performance, there are many other contributors, many of which, like the base oils used, who's roles are much more important. You can have a high VI polymer cocktail with some mediocre base stocks and a poo poo additive package that would lead to gummed up rings, varnish, coking, sludge, excessive wear....etc. A VI of 240 isn't going to fix a poorly blended product with horrendous oxidation and anti-wear performance.


That makes a lot of sense, well written!
 
Nissan developed parts of the GTR using M1 0W40 and specifically talk about recommending it's usage to guarantee performance. So that's a little bit beyond just an OEM relationship.

While you claim not to understand what I'm getting at, it's a simple point and I think you're just stirring the pot. I'm not claiming for a minute that VI is the most important thing so I don't know why you decide to attribute that to me. I am pretty certain that you and many others commenting here are not such great experts that you know for sure which elements are most important and to what degree.

I'm just refering to some interesting evidence, namely that the most highly thought of Euro oil, that is suitable for racing, happens to have the highest VI in it's class. And that it had an even higher VI when the modifiers were not as stable.

So some experts, whose relative expertise compared to you and me is far greater and more significant than your relative expertise to me, placed some importance to a high VI.

They even made VI the first point in a presentation they did about the advantages of synthetic oil. In many people's books, the order in which things are talked about signifies their importance. That of course might speak more to relative importance rather than absolute importance.

But hey if it makes you feel better to reply to me with a superior attitude, then go ahead. In the scheme of things it matters not.
 
Originally Posted By: S65AMG
Nissan developed parts of the GTR using M1 0W40 and specifically talk about recommending it's usage to guarantee performance. So that's a little bit beyond just an OEM relationship.


No, that's a somewhat typical OEM relationship with Mobil actually. GM does the same with the Corvette stuff, Honda did the same with developing their HTO-06 spec....etc. Mobil has the money to work hand-in-hand with OEM's on this stuff every step of the way. That's one of the reasons they are such a great partner to work with.

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While you claim not to understand what I'm getting at, it's a simple point and I think you're just stirring the pot. I'm not claiming for a minute that VI is the most important thing so I don't know why you decide to attribute that to me. I am pretty certain that you and many others commenting here are not such great experts that you know for sure which elements are most important and to what degree.


And you do? I mean we are all just [censored] into the wind here to some degree. I don't formulate lubricants for a living, but I do listen to the guys that DO know what they are talking about. One would be Molakule, who DOES formulate lubricants for a living and has never mentioned that VI is some holy grail. And Doug Hillary, who did extensive fleet testing for ExxonMobil and again, he never mentioned VI as being some earth shattering factor in his testing either
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I'm just refering to some interesting evidence, namely that the most highly thought of Euro oil, that is suitable for racing, happens to have the highest VI in it's class. And that it had an even higher VI when the modifiers were not as stable.


We don't know if it was the VII's that were "not stable" or that the VISOM base oil used in the SN version is just heavier than the PAO base they used in the SM version and subsequently the oil simply doesn't shear like the SM version did. I doubt there's a significant amount of polymer in M1 0w-40, SM or SN.

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So some experts, whose relative expertise compared to you and me is far greater and more significant than your relative expertise to me, placed some importance to a high VI.


Which experts? Again, I cite my Ferrari example and SOPUS.

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They even made VI the first point in a presentation they did about the advantages of synthetic oil. In many people's books, the order in which things are talked about signifies their importance. That of course might speak more to relative importance rather than absolute importance.


Well a naturally higher Viscosity Index is certainly an easy thing to point out, wouldn't you agree? An oil thickening less with cold and thinning less with heat is certainly a trait I'd make it a point in mentioning. That was touched on by me earlier, when I said that M1 0w-40 had a relatively high VI. Much of that VI is likely NATURAL, and a byproduct of the base oils used! I'm betting PU 5w-40 has next to zero polymer in it (it also has a PHENOMENAL NOACK) because of the GTL base stocks employed by SHELL. The natural VI of the product might not be as outstanding as that of M1 0w-40, but I bet the lubricant is more shear stable. There are ALWAYS trade-offs. However, that's one of the beautiful things about synthetic base stocks, and why they mentioned it, and that is that you don't need to use a lot of polymer to get a relatively high VI lubricant! That's an important point to consider! I'd much rather have more high quality base oil and less polymer in my lubricant. With modern synthetic base oils, that's exactly what these companies are doing. And there are other benefits, like low NOACK. M1 0w-40's of 8.8% for the SM version is still incredible. And that's a base oil function.

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But hey if it makes you feel better to reply to me with a superior attitude, then go ahead. In the scheme of things it matters not.


I don't think I'm being "superior", I think I'm putting more thought into this than you are. That's why I've taken the time to respond to your posts in the manner in which I have. I'm not trying to be rude, I'm trying to get you to consider some other angles on the subject of lubricants. We can't just look at one example and say "AH HA! That's proof because of XYZ". There are many different ways to skin a cat. I believe a relatively high VI like that of M1 0w-40 helps make the product a better lubricant. But I also believe that there's a lot more to it than just that. The product performs the way it does because XOM spent an ungodly amount of money developing it to perform that way. We can look at PU 5w-40, their relationship with Ferrari and its use, as well as the fact that there is a tremendous amount of overlap in terms of certs/approvals for both of these oils and see that they are two different ways to do much the same thing. M1 0w-40 has a higher VI. PU 5w-40 has a lower NOACK and better shear stability. Relative performance markers. Both oils are incredible in their own right. Do you see what I'm getting at?
 
Originally Posted By: OVERKILL
I mean we are all just [censored] into the wind here to some degree. I don't formulate lubricants for a living, but I do listen to the guys that DO know what they are talking about.

In some ways, I would agree that a very, very high VI would be a holy grail in the field of lubrication. However, that's not to say that a high VI at the expense of everything else required of that lubricant would be considered a holy grail of lubrication.

On the first point, an oil that doesn't change viscosity much over a wide temperature range is a great thing. On the second point, if such a lubricant doesn't do anything else very well, aside from maintaining viscosity, then it isn't much of a lubricant, now is it?

We also have to look at cost and market share - after all, the oil companies do. What is it going to cost an oil company to make a big increase in a VI? Will it put a popular grade (i.e. 5w-20 or 5w30) out of spec? I might not be averse to using a 0w-20 in a 5w-20 application or a 0w30 in a 5w30 application, but I'm probably not representative of the average oil buying public.
 
Again, it's incredible how you're saying I'm focusing on one aspect of an oils performance and how you're saying that I've said a high VI is the holy grail.

I've said no such thing. All I've said is that M1 0w40 is very well respected, and in comparison with it's competitors, has a relatively high VI. I don't have too much data on how this oil performs compared to it's competitors on other performance criteria but it's higher VI means it's going to be at the right viscosity over a wider temperature range. If Mercedes recommends it and is involved in it's design, this performance difference might very well be there intentionally.

As to who I'm listening to, well it's the Mobil engineers themselves. From what I've seen, for the current 0w40 they incorporated the "shear stable viscosity modifier" that was previously used in the ESP line but not in the previous 0w40.

I'm not making any value judgements on other oils, or other performance characteristics. I'm just pointing out that 0w40 meets perhaps the widest range of certifications and has a higher VI.

I would also point out again that Mobil believe that a higher VI leads to lower wear.

I think that is possibly more important than a drop from an incredible 8.8% NOACK to a sensational 6.6% NOACK.
 
Originally Posted By: Garak
Originally Posted By: OVERKILL
I mean we are all just [censored] into the wind here to some degree. I don't formulate lubricants for a living, but I do listen to the guys that DO know what they are talking about.

In some ways, I would agree that a very, very high VI would be a holy grail in the field of lubrication. However, that's not to say that a high VI at the expense of everything else required of that lubricant would be considered a holy grail of lubrication.

On the first point, an oil that doesn't change viscosity much over a wide temperature range is a great thing. On the second point, if such a lubricant doesn't do anything else very well, aside from maintaining viscosity, then it isn't much of a lubricant, now is it?

We also have to look at cost and market share - after all, the oil companies do. What is it going to cost an oil company to make a big increase in a VI? Will it put a popular grade (i.e. 5w-20 or 5w30) out of spec? I might not be averse to using a 0w-20 in a 5w-20 application or a 0w30 in a 5w30 application, but I'm probably not representative of the average oil buying public.

Garak well said.
I think you're one of the few that truly understands that a VI as high as technically possible without incurring a lot of trade- offs is indeed the lubrication holy grail of any automotive oil that operates under varying temp's. Viscosity is the most important attribute of an oil but it is of course it is not the only aspect.

There is a lot of conservatism with motor oil and brand loyalty.
Anything new is automatically pooh-poohed. I remember how much resistance their was to M1 0W-40 when it was first released which must be 15 years ago now. There was tons of criticism of how shear prone it was etc. and it was somewhat shear prone. But it was an OEM oil so it wasn't going away as it allowed the companies like Porsche that once specified every grade under the sun based on ambient temp's to now just spec' the one grade that solved a lot of warranty related lubrication issues. M1 0W-40 is now a benchmark oil that few companies can match.

When Toyota came out in 2009 with their 214 VI 0W-20, first just for the Prius, it was panned by many. Heck, in a discussion I had with Terry Dyson he predicted it would "shear all to H@ll". As we now know due to advances in polymer technology it's proven to be a very shear stable oil and it's now specked for most Toyota and Lexus models.

Nevertheless there is still a lot of resistance to high VI oils particularly if one's favourite brand isn't formulating one yet. That's when the excuses that VI isn't everything etc get bandied about which really is an obfuscation of the issue.
 
It's very simple logic and it makes perfect sense to me.

It would be nice if others discussed this in a technical manner rather than an argumentative manner.

I think we're missing out on some good discussion and exploration of exciting possibilities.
 
Originally Posted By: CATERHAM
I think you're one of the few that truly understands that a VI as high as technically possible without incurring a lot of trade- offs is indeed the lubrication holy grail of any automotive oil that operates under varying temp's.

This is the important part. After all, why were multigrade oils introduced? They were brought out, essentially, to improve viscosity index. Why did the Germans automakers change to a numbered spec from all kinds of different grades (including straight grades) depending on climate? While there were multiple reasons for doing so, a higher viscosity index allows better cranking (and protection) in cold weather without sacrificing HTHS.

And, as you mentioned, when new stuff comes out, people turn up their noses at it. People still fear the shear stability of 5w30 oils (and some people even fear a 10w30). Why use M1 0w-40 when the prescribed grade was 15w40 for years? Why 5w30 when 10w30 was good enough? I don't "need" the cutting edge of high VI oils. I'm glad, however, the lubrication engineers have been exploring and expanding that cutting edge for decades.

I'm always wary of tradeoffs. I don't want the oil shearing terribly. I don't want it to be a poor performer at other metrics. Others don't want to sacrifice OCI duration for a high VI. There are plenty of reasons to be cautious, and I accept that. Heck, I'm cautious about such things and worry about them, too. VI isn't terribly high on my list of concerns when I shop for oil. Heck, I'm not afraid to use 10w30. But, to think that it's low on the list of priorities for lubrication engineers would be very shortsighted.

Nonetheless, since the internal combustion engine was introduced, there has been one unflinching trend with respect to motor oil. It's not anything about thin or thick, or CAFE playing with thin grades, or the Europeans looking for thick grades. It's that VI has increased steadily, and that's been the pattern in North America/Japan and Europe.

Whether it's been to make a motor vehicle useful in severe winter conditions, to improve fuel economy for CAFE, to simplify maintenance through one grade over the year (Europe and here), all of this has been made possible by increasing VI. Of course, car magazines and the automotive histories we read never call it that. They talk about multigrades. They talk about the introduction of synthetics. They talk about how synthetics are great for very high and very low temperature applications. They talk about how oils can save [even small] amounts of fuel.

Really, they're all talking about viscosity index, whether they know it or not. No, I'm not going to go out looking for an oil with a 200+ VI. But, I know which way the wind is blowing, and it's been blowing that way since long before any of us here were driving.
 
Nice post Garak, and I couldn't agree more!

On the topic of mixing oils, which many of us do for multiple reasons (VI #, increase TBN, moly, slightly thin out or thicken the oil, etc.), this is something that eveyone does, including those who are so adamantly against it. What do I mean? Evey time that we have our oil changed and it is by a different manufacturer, we are essentially mixing different chemistries. You are never going to get 100% of the old oil out. This is precisely why we are told that when we change oils, to skip one OCI before doing an UOA to ensure that most of the old oil is out. And let's keep in mind that Mobil, the #1 synthetic oil manufacturer, says that it is OK to mix their oils.

I think we all agree that mixing oils isn't detrimental to the engine and that it can be beneficial depending on what exactly you want (and to be fair, Buster, did mention this).

I think we all agree that the viscocity index of an oil is very important, as long as other important aspects of the oil aren't compromised. And as Garak indicated in his brilliant post, this is the way of the future, whether you like it or not.

I think that we can all agree that it was just slightly ironic that our dear Buster, to make his point stronger about great oils with low VI, used Redline as an example
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Some of you guys have lost all the perspective. They pick too thick oil on the sale and they mix it with too thin oil to come with the right brew but then spend $30 on UOA to find if their ratio was right!

If I had to give an example of insanity, that would be it.
 
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