MOFT, HTHSV, VII, and wear: It's complicated

Status
Not open for further replies.
Originally Posted by ZeeOSix
So one reason I chose Valvoline Advanced 5W-30 full synthetic is because the HTHSV is 3.2 cP, KV100 is 10.2 cSt, VI = 158 and Noack 9.3%. The VI of 158 and KV100 of 10.2 seems to be on the low end for most 5W-30 full synthetics oils that I compared (ie, Castrol, Pennzoil, Mobil 1). So how does Valvoline Advanced 5W-30 get a relatively high HTSHV with a relatively low VI and KV100 compared to those other 3 brands which all have a HTHSV less than 3.2 and a VI greater than 158.


Having a low VI 158 means it has fewer VM polymer chains to get temporary shear during the high-stress HTHS conditions, hence the slightly higher HTHS 3.2. That's it.
Oronite explains it well: https://www.oronite.com/products-technology/viscosity-modifiers/default.aspx and look under "temporary and permanent viscosity loss", the + tab down that page.
 
Originally Posted by ZeeOSix
Originally Posted by Gokhan
Now, here is the million dollar question: Can an almost-VII-free HTHSV = 3.0 cP 5W-30 oil or even an almost-VII-free HTHSV = 2.6 cP 5W-20 oil made from a high-VI base oil protect against catastrophic wear better than an HTHSV = 4.0 cP oil with a very high VII content and a base-oil with a so - so viscosity index?

So one reason I chose Valvoline Advanced 5W-30 full synthetic is because the HTHSV is 3.2 cP, KV100 is 10.2 cSt, VI = 158 and Noack 9.3%. The VI of 158 and KV100 of 10.2 seems to be on the low end for most 5W-30 full synthetics oils that I compared (ie, Castrol, Pennzoil, Mobil 1). So how does Valvoline Advanced 5W-30 get a relatively high HTSHV with a relatively low VI and KV100 compared to those other 3 brands which all have a HTHSV less than 3.2 and a VI greater than 158.

Originally Posted by oil_film_movies
Originally Posted by ZeeOSix
So one reason I chose Valvoline Advanced 5W-30 full synthetic is because the HTHSV is 3.2 cP, KV100 is 10.2 cSt, VI = 158 and Noack 9.3%. The VI of 158 and KV100 of 10.2 seems to be on the low end for most 5W-30 full synthetics oils that I compared (ie, Castrol, Pennzoil, Mobil 1). So how does Valvoline Advanced 5W-30 get a relatively high HTSHV with a relatively low VI and KV100 compared to those other 3 brands which all have a HTHSV less than 3.2 and a VI greater than 158.

Having a low VI 158 means it has fewer VM polymer chains to get temporary shear during the high-stress HTHS conditions, hence the slightly higher HTHS 3.2. That's it.
Oronite explains it well: https://www.oronite.com/products-technology/viscosity-modifiers/default.aspx and look under "temporary and permanent viscosity loss", the + tab down that page.

Originally Posted by ZeeOSix
oil_film_movies ... thanks for the link, good info.

We can attempt to answer ZeeOSix's question using my base-oil/HTHSV calculator.

https://www.bobistheoilguy.com/foru...erature-full-shear-viscosity#Post5113871

I plugged in the values from the Valvoline PDS and fine-tuned some of the HTHSV values to three significant figures or more rather than the two reported -- one of the strengths of the calculator is that you can determine the HTHSV more accurately if you know the base-oil type.

This is what I got. Note that these are all estimates and subject to error, especially thanks to the PDS data:

Code
Oil HTHSV BO KV100 BO VI relative VII content BO DV150



VAS 0W-16 2.35 cP 6.25 cSt 152 0.64% 2.2 cP

VAS 0W-20 2.68 cP 6.54 cSt 150 1.8% 2.2 cP

VAS 5W-20 2.70 cP 7.86 cSt 145 0.23% 2.6 cP

VAS 5W-30 3.225 cP 8.31 cSt 144 1.7% 2.7 cP

VAS 10W-30 3.20 cP 6.81 cSt 118 4.3% 2.2 cP

The results are suggesting that all VAS grades except the 10W-30 are made of Group III+++ base oils with extremely high VI and contain very little VII. 10W-30 on the other hand is made from a low-quality Group III with a minimal VI and contains more VII. This makes sense because otherwise, it would classify as a 5W-30, not 10W-30, since higher VI base stocks have lower CCS.

Also note that VAS 5W-20 and VAS 5W-30 have extremely high base-oil dynamic viscosity at 150 °C (BO DV150) because of the high-VI base oil and low VII content.

Shell makes the so-called XHVI (extra-high viscosity index) base stocks. In fact, XHVI seems to be a form of GTL made in Bintulu, Malaysia. However, the KV100 = 8.3 cSt XHVI base stock has Noack = 5%, which doesn't agree with the Valvoline PDS. So, perhaps they sourced some very high VI Group III+++ base stocks from another company.

https://prodepc.blob.core.windows.net/epcblobstorage/GPCDOC_GTDS_XHVI_5.2.pdf
https://prodepc.blob.core.windows.net/epcblobstorage/GPCDOC_GTDS_XHVI_8.2.pdf


To me it looks like the magic here is that Valvoline chose to use an 8 cSt Group III base stock with an extremely high VI for their VAS 5W-20 and VAS 5W-30. Normally an 8 cSt base stock may not be capable of making a 5W-xx oil because of its CCS @ -30 °C may be to high but these Group III+++ and GTL base stocks with very high VI have very low CCS values.

If my estimates are correct, Valvoline Advanced Synthetic 5W-20 and 5W-30 easily win over all other oils in terms of the viscosity performance: extremely high VI base oil, very high base-oil viscosity at 150 °C, and very low VII content.

[Linked Image]
 
Originally Posted by Gokhan
If my estimates are correct, Valvoline Advanced Synthetic 5W-20 and 5W-30 easily win over all other oils in terms of the viscosity performance: extremely high VI base oil, very high base-oil viscosity at 150 °C, and very low VII content.
Let us assume for a moment that your estimates are all absolutely correct. In real world terms, in what manner does VAS "easily win over all other oils in terms of the viscosity performance"? What tangible attributes will be evident?
 
Originally Posted by 2015_PSD
Let us assume for a moment that your estimates are all absolutely correct. In real world terms, in what manner does VAS "easily win over all other oils in terms of the viscosity performance"? What tangible attributes will be evident?

That's the topic of this thread if you read it from the beginning.
 
Originally Posted by oil_film_movies
Having a low VI 158 means it has fewer VM polymer chains to get temporary shear during the high-stress HTHS conditions, hence the slightly higher HTHS 3.2. That's it.
Oronite explains it well: https://www.oronite.com/products-technology/viscosity-modifiers/default.aspx and look under "temporary and permanent viscosity loss", the + tab down that page.

I tried changing the adjustable parameter in my calculator which accounts for the VII type, normally set at 13.7, between 8 and 16 and the results for the VAS are fairly robust -- suggesting a high-VI base oil with a high KV100.

Therefore, I'm more inclined to think that the magic is the high-VI base oil here and not the VII type. It's also hard to believe that the VAS would use an unusual VII and still pass all the engine tests. Besides, adjusting the VII parameter doesn't seem to drastically change the results in my calculator.

Another explanation is that there is no magic and the reported HTHSV values in the PDS are inflated from their actual values that are lower.
 
Originally Posted by Gokhan
I plugged in the values from the Valvoline PDS and fine-tuned some of the HTHSV values to three significant figures or more rather than the two reported -- one of the strengths of the calculator is that you can determine the HTHSV more accurately if you know the base-oil type.

What your evidence of this? How are you verifying a more accurate HTHS value then was published by an oil company, without actually conducting HTHS tests yourself?

I can calculate (guesstimate) your mass if you give me your height and BMI, but I doubt I'll have more significant figures than if you step on the scale and post the result here.
 
Originally Posted by Gokhan
Another explanation is that there is no magic and the reported HTHSV values in the PDS are inflated from their actual values that are lower.


I doubt Valvoline is going to advertise false specifications, as any competing big oil maker can verify and challenge those specs if deemed necessary.
 
Originally Posted by Gokhan
Originally Posted by oil_film_movies
Having a low VI 158 means it has fewer VM polymer chains to get temporary shear during the high-stress HTHS conditions, hence the slightly higher HTHS 3.2. That's it.
Oronite explains it well: https://www.oronite.com/products-technology/viscosity-modifiers/default.aspx and look under "temporary and permanent viscosity loss", the + tab down that page.

I tried changing the adjustable parameter in my calculator which accounts for the VII type, normally set at 13.7, between 8 and 16 and the results for the VAS are fairly robust -- suggesting a high-VI base oil with a high KV100.

The effective adjustable parameter in the calculator corresponds to the ratio of the VII viscosity-boost rate to the VII temporary-shear rate.

Therefore, if these two rates have a tendency to be proportional to each other when you vary the VII type, the calculator would be more robust to the variations of the VII type.

If I change it by a factor of two, I can get the base-oil viscosity down to a normal Group III with VI = 130.

So, is this a very unusual VII or a base oil with a VI close to 150? We'll never know unless there is additional information.
 
Originally Posted by Gokhan
Originally Posted by 2015_PSD
Let us assume for a moment that your estimates are all absolutely correct. In real world terms, in what manner does VAS "easily win over all other oils in terms of the viscosity performance"? What tangible attributes will be evident?
That's the topic of this thread if you read it from the beginning.
I did and see no indication of how VAS "easily wins" nor do I see any tangible evidence that VAS will perform any better (or worse) than any other oil. These discussions are great from a theoretical point of view, but I fail to see how you can present these statements as facts (if that is what you are doing and it appears that you are).
 
Regarding the VII type, PMA VII has a viscosity-boost rate that increases with the temperature. However, it requires a very high polymer content, which could increase the deposit formation.

I doubt it's using PMA VII. It probably has a thick high-VI base oil. The detergent inhibitor (DI) package thickens the base oil as well.
 
Status
Not open for further replies.
Back
Top