Rethink and understand SAE viscosity: a 0W-20 can be thicker than a 0W-40 or 5W-40

Gokhan said:
Chevron, Nissan, and others studied it.

https://bobistheoilguy.com/forums/t...ll-shear-viscosity.307409/page-2#post-5073782

https://bobistheoilguy.com/forums/t...ll-shear-viscosity.307409/page-4#post-5085549
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You have any links you can post in this thread that show controlled testing data that shows how the wear rates on actual engines under high RPM and high loads deviate between the standard HTHS ratings of oils and their actual HTFS, and by how much they deviate as the shear rates keep increasing above 1M/sec ?
 
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aquariuscsm said:
Yep, and if my memory serves me correctly, didn't the pao thing begin when P66 bought out Redline?
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I think it was RL misrepresenting things a bit even prior to that. The very expensive racing oils were mostly POE but their (still very expensive) street oils were various blends, with POA being dominant. Usually they were referencing their racings oils in advertising without implicitly stating as such and inferring all their oils were mainly POE.......
 
Jackson_Slugger said:
I think it was RL misrepresenting things a bit even prior to that. The very expensive racing oils were mostly POE but their (still very expensive) street oils were various blends, with POA being dominant. Usually they were referencing their racings oils in advertising without implicitly stating as such and inferring all their oils were mainly POE.......
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I found a reason they’re probably jettisoning PAO for GTL, other than the cost: look at the top negative for PAO- it doesn’t degrade on its own. Pretty sure several of the GTLs say something like in less than a month they biodegrade in their respective SDSs.
 
Jackson_Slugger said:
I think it was RL misrepresenting things a bit even prior to that. The very expensive racing oils were mostly POE but their (still very expensive) street oils were various blends, with POA being dominant. Usually they were referencing their racings oils in advertising without implicitly stating as such and inferring all their oils were mainly POE.......
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SubieRubyRoo said:
I found a reason they’re probably jettisoning PAO for GTL, other than the cost: look at the top negative for PAO- it doesn’t degrade on its own. Pretty sure several of the GTLs say something like in less than a month they biodegrade in their respective SDSs.
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Well. @High Performance Lubricants is the new Bee's Knees.

I was always under the impression they were primarily Group V. As a younger man, I was amazed by what their oil delivered, in very unscientific analysis and application. Turbo engine . Made an impression on me, and that superior formulated oils were in fact able to deliver.

They are no longer the King Of The Hill.. the example was made, specifically, that they chose to market their either HTHS 2.9 or 3.0 oil as a 0W-20, and that was unusual and perhaps another misrepresentation.

I have nothing bad to say about them. Dave from HPL is a wonderful individual and told me about not making rudely bad statements about competitors. This thread, I believe, is about J300 oil grades, and I cant see how it isn't relevant even to today.
 
Rand said:
I cant get behind this whole idea? At this point it is what exactly?
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In a nutshell, HTHS (measured at a shear rate of 10⁶ s⁻¹) is more relevant to an oil's performance in an engine than the low-shear KV (measured as shear rate → 0), and HTFS (measured at a shear rate of 10⁷ s⁻¹ or higher (as shear rate → ∞)) is more relevant to an oil's performance in an engine than HTHS.

(Note that the shear rate equals to the relative speed of the sliding parts divided by the clearance between them.)
 
Gokhan said:
In a nutshell, HTHS (measured at a shear rate of 10⁶ s⁻¹) is more relevant to an oil's performance in an engine than the low-shear KV (measured as shear rate → 0), and HTFS (measured at a shear rate of 10⁷ s⁻¹ or higher (as shear rate → ∞)) is more relevant to an oil's performance in an engine than HTHS.

(Note that the shear rate equals to the relative speed of the sliding parts divided by the clearance between them.)
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But how far off is HTHS as an indicator of wear as compared to the HTFS ... with all other variables held constant? Is it 1%, 5%, 20%, 100% difference?

Yes, in theory if an oil shears down way more than it's viscosity measured at the standard HTHS (150C @ 1M/sec shear rate), then there would be less MOFT and more wear. But how many engines are running in cases where the shear rate is way above 1M/sec? Yes, I know it's been shown that some engine components can shear oil higher than the 1M/sec, but they would have to be used in situations like a race car to make it live in that realm a lot of the time. There is still a reason cars used for track use are specified a higher viscosity oil .. because in most cases higher viscosity means higher HTHS which will also mean higher HTFS (as shown in your Excel spreadsheet), except in some outliers that have some pretty high VII percentage.

What's with that Toyota TGMO 0W-20 SN in your table (ranking oils from highest HTFS to lowest) that's 2nd from the bottom with a HTFS of only 1.55 cP?

And what's with the Valvoline Daily Protection SAE 30 SP (row 11) that has a HTFS higher than the HTHS, and a negative VII content % with a VI of 99 ?

1666923448618.png
 
aquariuscsm said:
Same here. They still advertise "Ester based oil" on their website. No mention of PAO base. Copy and paste from their 20W-50:

  • Full-synthetic ester formula for passenger cars, light trucks, performance vehicles and marine applications
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It's been covered like 400x how have you missed it? It has some ester content, but the majority of the base oil is PAO. The SDS sheets showing that have been posted on here countless times. Their customer service has also confirmed that "a large portion" of the base oil is PAO at one time or another as well. It makes sense.
 
Here's a snip-it from some old study I have someplace ... it's so old that the document looks like it was typed on a typewriter. Temporary shear due to increasing shear rates were known about a long time ago, hence why the HTHS was eventually added to SAE J300 quite a while ago. And it shouldn't be a big surprise that as the shear rate keeps increasing above 1M/sec that muti-viscosity oils could have the potential to temporarily shear down to basically what the base oil would shear to at that temperature and shear rate if all the VIIs gave up the ghost at higher and higher shear rates. So low viscosity base oils with lots of VII have the potential to exhibit temporary shear more than oils that have a higher base oil viscosity and less VIIs. Pretty much all the oils at the top of your ranked HTFS column in the spread sheet are 10W, 15W or 20W oils (higher base oil viscosity oils).

1666923871134.png
 
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schwinney said:
Thank you... ", got any other spurious posits you'd like to make?"

lol.



Hey.

I appreciate knowing I wasnt coming out of nowhere. Thank you @aquariuscsm
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How have you two missed this? I'm dead serious, is this selective amnesia? Like, with over 40 accounts on here spanning a decade, you absolutely have to have seen these discussions, there is no way you missed them.

Here's a recent one:
https://bobistheoilguy.com/forums/t...-pentastar-3-6-v6.355183/page-10#post-6129252

This is from the white bottle 5W-30:
1666923874608.webp


Two PAO's, one less than 60%, the other less than 30%.

And Joe, YOU POSTED IN THAT THREAD!!!! So you clearly read it! Good God! :oops:
 
OVERKILL said:
It's been covered like 400x how have you missed it? It has some ester content, but the majority of the base oil is PAO. The SDS sheets showing that have been posted on here countless times. Their customer service has also confirmed that "a large portion" of the base oil is PAO at one time or another as well. It makes sense.
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They need to change the verbiage on their website. Just sayin. :D
 
aquariuscsm said:
They need to change the verbiage on their website. Just sayin. :D
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It's carefully crafted, just like the wording used by Motul, to get folks to think it's "ester oil". While it does have some significant ester content, the majority of the base oil blend is PAO, which makes perfect sense for an automotive engine oil, it's not going in a jet turbine.
 
SteveG4 said:
I suppose maximizing profits remains the "name of the game" for most, if not all, of the mfgrs and blenders. And or how much they can get away with... :cool:

I suppose that's why we crazies here are so bloody mindful? :)

HPL appears to do its best to produce a top-notch product regardless. They do charge for that premium product though ... as they should. :)
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Better lubricant costs more money but the return may just make up for it especially on the track or rigerous operating conditions.
 
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