Viscosity Index Improvers are not bad.

I have a question. Do viscosity modifiers break down when there is fuel dilution? The reason I'm asking is I've noticed over the years that Redline rarely drops a a a grade even when there is fuel dilution and it appears that oils with a larger spread, which often indicates more VII, tend to lose a greater percentage of their viscosity than those with a narrow spread. Is this due to the concentration of viscosity modifiers? Thank you
 
Originally Posted by buster
I have a question. Do viscosity modifiers break down when there is fuel dilution? The reason I'm asking is I've noticed over the years that Redline rarely drops a a a grade even when there is fuel dilution and it appears that oils with a larger spread, which often indicates more VII, tend to lose a greater percentage of their viscosity than those with a narrow spread. Is this due to the concentration of viscosity modifiers? Thank you

That's correct! This is the reason why only monograde oils are specified for two-stroke-cycle diesel engines. VII and fuel dilution do not mix.

However, the reason is not because the VII breaks down with fuel dilution. VII amplifies the viscosity at all (operating) temperatures by the same constant. In other words, KV is multiplied by the same constant at 40 C and 100 C. When there is fuel dilution, the base oil viscosity is reduced and this multiplication constant amplifies the effect.
 
Originally Posted by Solarent
I've been reading lots of posts recently about Viscosity Index Improvers (also called Viscosity Modifiers) and there is an idea perpetuated (and that is often repeated) that needs correcting:

Oils with little to no Viscosity Modifiers are not better than those that do have them. Neither can you compare oil performance based on how much or how little VM they have.

In fact, there are very few (if any) engine oils that do not contain some kind of viscosity modifier. The reason for this: it is next to impossible to meet the current viscosity profiles in the J300 without them. Unfortunately contrary to common belief - Group III synthetics, PAO's and esters all have excellent viscosity performance relative to temperature changes - but they almost always require some kind of VM to enable the non-newtonion viscosity performance required by todays engines.

So why do VM's continue to get such a bad wrap? It stems from a misunderstanding of what a VM is, how it operates and what types are being used. A long time ago VM's were simple polymers which could alter to the viscosity-temperature relationship of monograde oils. This is how multi-grade oils were born. However, in today's market VM's are much more complex than that - just look at this list:

Types and typical usages of VMs include:
  • Polyisobutylene (PIB) was the predominant VM for engine oil 40 to 50 years ago. PIBs are still used in gear oils due to their outstanding load carrying characteristics. PIBs have been replaced by Olefin Copolymers (OCP) in engine oils due to their superior cost effectiveness and performance.
  • Polymethacrylate (PMA) polymers contain alkyl side chains that interfere with the formation of wax crystals in the oil, providing excellent low-temperature properties. PMAs are used in super fuel economy engine oils, gear oil and transmissions fluid formulations. Generally, they have a higher cost than OCPs.
  • Olefin Copolymers (OCP) see extensive use in engine oils due to their low cost and satisfactory engine performance. Many OCPs are on the market, differing in molecular weight and the ratio of ethylene to propylene content. OCPs are the dominate polymer used for viscosity modifiers in engine oils.
  • Styrene Maleic Anhydride Ester Copolymers (Styrene Esters) are multi-functional VMs. A combination of various alkyl groups provides excellent low-temperature properties. Typical usages for Styrene Esters are fuel efficient engine oils, automatic transmission fluids, and in pour point depressants. Generally, they also carry a higher cost than OCPs.
  • Hydrogenated Styrene-Diene Copolymers (SBR) are characterized by fuel economy benefits, good low-temperature properties, and superior deposit control performance compared to most other polymers.Hydrogenated Radial Polyisoprene polymers have good shear stability at relatively low treatment rates compared to some other types of VMs. Their low-temperature properties are similar to OCP.


As you can see there are many types of VM - each with a different purpose, treat rate and function. In many cases the VM imparts multiple advantages that go above and beyond just fluid thickening and selecting the right VM can be critical to the success of a fluid protecting engine parts.

All engine oil manufacturers use VM's in their formulas. And depending on the base oil mix and desired SAE grade there are different treat rates ranging from 6%-15%. Less VM does not necessarily mean better. Usually the formula is optimized to meet the required SAE J300 grade and support the base oils which the marketer has chosen to use. Molecules of different shapes, patterns and lengths are all chosen to suit the performance requirements of the oil. The treat rate also changes based on what viscosity grade and base oils are used.

For example take this chart recently posted by Shannow (sourced from XOM Chemical):
[Linked Image]


As you look across the 0W grades notice that the Heavier weighted oils 0W30, 0W40 each have a higher concentration of the lightest base oil than the 0W20. Also notice that the concentration of VM also increases. This is also true of the 5W30 vs 5W40

Why would that be? Logically it makes more sense to use base oils that closer to the final viscosity grade right? Actually the answer is the opposite. In order to meet the viscosity performance profile a marriage between a high quality VM and base oils is the answer. Also note that all of the base oils used are much lighter than the minimum requirements to meet the required grade so it is basically impossible to meet the current SAE grade without the use of some kind of VM.

So how do companies get away with saying they little to no VM in an attempt to woo you to their products? Well, most of these companies are referring to PIBs and short chain OCP's which can be replaced by other polymers which much more shear-stable. Some companies use PMA's and Styrene Esters, which very different than traditional OCP's. XOM Chemical also produces mPAO's which are sometimes used as VM's.

For more information read http://www.pceo.com/articles/viscosity-modifier-four-part-article-series
(this has been posted before)

As you can see, VII's are much more complex than we often think, so if you don't know what you are talking about it can be easy to think that eliminating them or using oils that aren't supposed to have any would be better. This just isn't true and I doubt you will find an oil marketer anywhere that will give you real specifics about the type and concentration of their VM's in their formulas.

It's good that you studied a lot, but I would like to let you know that your main conclusions are wrong.

While it's true that the VMs (alternatively called VIIs) are not necessarily bad, they do affect the performance in negative ways for a given HTHSV spec.

For example, they are simply plastics and could increase the engine deposits and sludge in a very large amount depending on the type.

They are a no - no with severe fuel dilution as I explained in my previous post.

With the increasing VII content, the base-oil viscosity used in the oil gets lower, which increases the valvetrain, timing chain, and ring/liner wear. HTHSV is not the only viscosity that determines the wear of these components.

Shear stability is usually your least concern with VII.

Also, you mentioned many different VII types but almost all oils these days use OCP VII because the other types can't pass the modern engine-deposits tests, especially the turbocharger-deposits tests. Again, VII is simply a plastic, and you need to find the best one that does not leave a significant amount of engine deposits under high temperature.

For example, Euro 0W-20 oils (ACEA C5 category) use very little VII so that they can pass the stricter Euro and OEM tests.

I did use TGMO 0W-20 with higher VII content in the past, not specifically because I liked more VII, but I liked the add pack. It performed well in my application. The viscosity is a little lower when cold, which is a good thing of course but not necessarily important. If everything else is equal, you will be better off with an oil with less VII.

Here is my calculation of the VII content and base-oil viscosity for common oils:

https://www.bobistheoilguy.com/foru...erature-full-shear-viscosity#Post5090891
 
Originally Posted by Gokhan
Originally Posted by buster
I have a question. Do viscosity modifiers break down when there is fuel dilution? The reason I'm asking is I've noticed over the years that Redline rarely drops a a a grade even when there is fuel dilution and it appears that oils with a larger spread, which often indicates more VII, tend to lose a greater percentage of their viscosity than those with a narrow spread. Is this due to the concentration of viscosity modifiers? Thank you
That's correct! This is the reason why only monograde oils are specified for two-stroke-cycle diesel engines. VII and fuel dilution do not mix.

However, the reason is not because the VII breaks down with fuel dilution. VII amplifies the viscosity at all (operating) temperatures by the same constant. In other words, KV is multiplied by the same constant at 40 C and 100 C. When there is fuel dilution, the base oil viscosity is reduced and this multiplication constant amplifies the effect.

Thinking about it more carefully, it's not that you get a larger effect for fuel dilution with the VII but the viscosity loss due to the permanent shear of the VII adds to the viscosity loss due to the fuel dilution.

So, you're seeing the combined effect of the fuel dilution of the oil and permanent shear of the VII, which is larger than each effect.

viscosity = {base-oil viscosity} * {1 + [(VII boost factor) * (VII content)]} * {1 - [(VII shear factor) * (VII content)]}

The typical VII boost factor is around 13.7 for OCP VII for a given fraction of VII content: You get about a 13.7% boost in the viscosity for each percent of the VII content. The VII temporary-shear factor is about 2.0 for the OCP VII but the VII permanent-shear factor will vary with the specific VII and engine.

Last but not least, the base-oil viscosity is crucial in preventing wear of the valvetrain, timing chain, and rings/liners. The more the VII content, the lower the base-oil viscosity is, and if you add the fuel dilution to that, you get an even lower base-oil viscosity.

The permanent VII shear and reduced base-oil viscosity is probably why multigrade oils are not recommended but monograde oils are recommended instead for two-stroke-cycle diesel engines, which have severe fuel dilution. These engines also have twice the power density, which increases the ring/liner wear further, which in turn requires a thicker base oil.

Therefore, for most applications, a good OCP VII, or perhaps any halfway decent VII, will not cause a problem. Nevertheless, you will always have an additional margin of safety and more wear protection with less VII content for a given HTHSV spec, not to mention that it will help with the protection against the formation of the engine and turbocharger deposits.
 
Thank you Gokhan.

The areas of concern that you mention in the boldface,
are exactly those that I need to deal with.

Experience, in the form of driving a 2005 Tacoma with 2TR FE engine for 750k miles.
has taught me to beware of oil consumption, starting at about 150k miles. Poisoned cats cause smog check failures. Duh.

On my 2018 Tacoma, with this same engine, I am concerned about piston ring coking and valve stem, valve seat wear. Valve train and timing chain wear and are also to be dealt with. I actually have had a timing chain break on me, on an old 22RE, at about 400k miles.

The story about Red Line Oil is that it has very high natural VI, from the basestock, and virtually no need for VII's. This is a prime candidate for me, moving forward. I would add Signature Series and M1 EP, all in the 0W20 grade.

I do remember Carolina guy with the million mile Tacoma, again with the 2TR FE engine, using Castrol HM 5W20 w/ its low phosphorus. Of course that's a whole different ball game, with regard to base oil.

So much for my stash of five 5 quart jugs of Pennzoil Gold 0W20.. I will give it away.

Long live the Gokhan BBQ chart and HTHSV.
 
What do you suppose Penzoil Platinum Pure Plus 5w20 HTHS would be? 2.6ish? Its not on the list and is what im running so was just curious about the numbers.
 
Originally Posted by GaryPoe
What do you suppose Penzoil Platinum Pure Plus 5w20 HTHS would be? 2.6ish? Its not on the list and is what im running so was just curious about the numbers.
Likely 2.7±1.

I'm currently "running" it too.
 
Originally Posted by CR94
Likely 2.7±1. ...
Whoa! I meant 2.7±0.1. (Too late to edit that error in my previous post ... )
 
Last edited:
The last known Pennzoil Platinum HTHSV values, before the PurePlus formula change and before the subsequent SN PLUS formula change:

[Linked Image]


Therefore, 2.6 cP for both 0W-20 and 5W-20 is more likely to be the current HTHSV value, as Pennzoil is very conservative about its KV and HTHSV viscosity numbers.
 
Originally Posted by ZeeOSix
July 2010 is their latest HTHS info?
eek.gif


Shell figured out that many people are obsessed with HTHSV and Noack and base their oil selection on them, and it has stopped publishing them as a result.

I think Shell is actually hurting themselves because the lack of published specs is reducing the public trust in its oils, making them less appealing and less popular.

Exxon Mobil at least publishes HTHSV.

Unfortunately, PQIA doesn't test for HTHSV.

Shell had Noack available briefly when the Qatar Pearl PurePlus GTL base oil was first introduced:

https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/4718980/Pennzoil_Platinum_and_Ultra_Pl

HTHSV and Noack are very important properties. Noack could indicate the base-oil quality when the CCS viscosity is accounted (hence, my base-oil quality index). HTHSV has wear-protection implications and it could also be used to determine the VII content and base-oil viscosity, which have implications on wear and engine deposits [hence, my base-oil viscosity (HTFSV) calculations].
 
Originally Posted by Gokhan
I think Shell is actually hurting themselves because the lack of published specs is reducing the public trust in its oils, making them less appealing and less popular.
Based upon what data set? Historically, Shell has been in the top 5 and exactly how many consumers look at these specifications and decide on an oil brand/type? Oh, we may grind the minutiae here, but do we actually believe that Joe Consumer does?
 
"Joe Consumer" goes by how cool the oil jug/bottle looks and the cost. Only true oil nerds know what HTHS and Noack is and why it's important.
grin2.gif
 
Originally Posted by 2015_PSD
Originally Posted by Gokhan
I think Shell is actually hurting themselves because the lack of published specs is reducing the public trust in its oils, making them less appealing and less popular.
Based upon what data set? Historically, Shell has been in the top 5 and exactly how many consumers look at these specifications and decide on an oil brand/type? Oh, we may grind the minutiae here, but do we actually believe that Joe Consumer does?

I wouldnt be here if I wasnt curious on what I was buying. A simple search to look what people thought about Motorcraft oil, and what would be better than it took me to bitog where I began reading non stop and well, here I am. There are hundreds more people reading this stuff that are not registered getting their own ideas reading these forums as we speak. A percentage of Joe Consumer is in fact listing...
 
Originally Posted by GaryPoe
Originally Posted by 2015_PSD
Originally Posted by Gokhan
I think Shell is actually hurting themselves because the lack of published specs is reducing the public trust in its oils, making them less appealing and less popular.
Based upon what data set? Historically, Shell has been in the top 5 and exactly how many consumers look at these specifications and decide on an oil brand/type? Oh, we may grind the minutiae here, but do we actually believe that Joe Consumer does?
I wouldnt be here if I wasnt curious on what I was buying. A simple search to look what people thought about Motorcraft oil, and what would be better than it took me to bitog where I began reading non stop and well, here I am. There are hundreds more people reading this stuff that are not registered getting their own ideas reading these forums as we speak. A percentage of Joe Consumer is in fact listing...
I am not disagreeing that hundreds perhaps even thousands are "reading this stuff" as you say. What I am saying is the average person (read this millions) is not looking at the specifications and making a decision (if they understand what they are looking at all)--they are looking at and succumbing to the advertising AND the price of the oil. In the grand scheme of things, no longer printing part of the specifications for the world to read will have a minuscule impact as that relates to advertising and an oil company's sales. This "seat of the pants" perception of mine is qualified by noting that Shell/ Pennzoil is always in the upper group of motor oils sold in the US.
 
Originally Posted by ZeeOSix
"Joe Consumer" goes by how cool the oil jug/bottle looks and the cost. Only true oil nerds know what HTHS and Noack is and why it's important.
grin2.gif



You forgot to put this at the end of your post:

*Pushes up glasses*
 
Originally Posted by JLTD
Originally Posted by ZeeOSix
"Joe Consumer" goes by how cool the oil jug/bottle looks and the cost. Only true oil nerds know what HTHS and Noack is and why it's important.
grin2.gif



You forgot to put this at the end of your post:

*Pushes up glasses*


LoL ...
cool.gif
 
Originally Posted by userfriendly
Good thread to bump up Buster. I've yet to disagree with anything Solerant has written.

And even SonofJoe agrees with Solerant on this.
 
A quick read on turbocharger deposits. There's a section which addresses VII (OCP vs Star). Might be worth reading if you're one who likes to run HDEO such as T6 in the hotter running turbo-gasser.

LINK
 
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