How is different HTHS achieved in oils with the same viscosity?
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Viscosity Index Improvers and/or choice of base oils with their various viscosities.
Remember that there's a range for every grade. For example with regards to a 30W the KV100C is 9.3 to < 12.5 cSt. The higher hths will almost always be over 11cSt.
Remember that there's a range for every grade. For example with regards to a 30W the KV100C is 9.3 to < 12.5 cSt. The higher hths will almost always be over 11cSt.
Shel_B
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Not asking a bout viscosity ... the question was about HTHS.
Right and I gave you that answer. Amount of VII's and choice of base oils. This is represented by the fact that there's a viscosity range for 30w like other weights. It's why the high HTHS 30w typically have a KV@100C of no less than 11 cSt.
M1 ESP KV@100C 12 cSt.
M1 EP KV@100C 10.6 cSt.
You'll never know exactly how every brand does it because that's a trade secret. For example for all we know M1 has 2-3 base oil blends for 30w and they tweak it with VII's in order to meet various hths requirements.
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The point was that an oil with higher HT/HS will have higher kinematic viscosity, even though it'll still be within the 30 grade range. A 30 grade represents a range of kinematic viscosities (from 9.3 cSt all the way up to 12.5 cSt), not just a single one. So, a low HT/HS oil will be at the lower end of that 30 grade range, and a high HT/HS oil will be at the higher end of that 30 grade range.
Yep, the fact that they are grades and not "viscosity" makes up a big part of the difference.
Shel_B
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My apologies ... some of your answer didn't appear on my screen. In any case, this fleshes it out a bit. Thanks!
Shel_B
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This, and Quattro Pete's answer are helpful, but they open the door to another question.
M1 EP 5W-30 has a vis of 10.6 and the M1 EP 5W-30 High Mileage has a vis of 11.8 according to charts I have here. Are you suggesting that the HM variant has a greater HTHS?
It may or it may not. HT/HS is usually measured using ASTM D4683 which produces whatever result it produces. You're measuring a more complicated (and better representative) value of the oil than just the viscosity.
How is HTHS Viscosity Measured
One method used to measure high temperature high shear (HTHS) viscosity is ASTM D4683.
360.lubrizol.com
It's possible. For example both meet ACEA A5/B5 which has a HTHS range of 2.9 - 3.5. So EP could fall within the bottom of that range and the EP HM could fall within the upper limit of that range. M1 is annoying in that their literature just doesn't tell you. Perhaps look for it on their German or GB website?
Edit: Never mind. I checked the German site and they don't have those products.
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After they are done damaging our engines with lowest cSt that they can get away (but with great fuel economy), they are recommending "High Mileage" with the selling point that will prevent the wear to extend further
Who is they?After they are done damaging our engines with lowest cSt that they can get away (but with great fuel economy), they are recommending "High Mileage" with the selling point that will prevent the wear to extend further
I think it is a combination of Russian Hackers and the BORG. The BORG ship is in orbit but it is cloaked.
They will reveal themselves at the appropriate time. Likely at around 233K miles when your engine is already worn out.
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sorry.
An interesting excercise is to plot KV100 vs HTHS for a bunch of oils in the same viscosity grade. A curve fit of the data will be linear, but there will be some scatter above/below the linear fit line due to variations in base oils and VIIs. That's why oils of basically the same KV100 won't have the same HTHS. In the end, HTHS matters more than KV100.
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HTHS, remember, is "high temperature, high shear". So there are two fundamental differences between how this and kinematic viscosity (KV) are measured:
- High temperature - the HTHS test is run at 150°C whereas the KV test used to define an SAE grade is run at 100°C. So if you had two oils with the same KV100 but with different VIs, the higher VI product will have a higher viscosity at 150°C than the lower VI oil.
- High shear - the KV test is run at essentially zero applied shear rate; the oil falls down the bore of a glass tube under its own weight; the result will depend on everything that's in the oil. The HTHS test is run at 10⁶ s⁻¹ shear rate, which has the effect of essentially removing the viscosity uplift of the shear-fragile VII and revealing the underlying viscosity of the base oils (which are effectively shear resistant). So an oil which relies on lots of VII for its KV100, will show a reduced HTHS.
Exactly, two different tests for two different properties with two different results. And one is a much better representation of how things work in an ICE.
Thank you for posting that.
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