Why we should love HTHS specs:
- Thread starter tundraotto
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When it doubt, high HTHS.
Always as high as possible HTHS - for me.
(Mobil 1 15W-50 is still my friend after all these years with the 4.5 HTHS)
Why stop at 50?
because I care about the HTHS of 4.5 more than the 50....I use it on all my OPE. The price is decent also.
I asked why you stopped at 50? You can always go 60
Well, Redline 20W-50 has a higher HTHS (6.1) than Redline 10W-60 (5.8)...
If it was a tad over $20/5qts at walmart - I probably would!I asked why you stopped at 50? You can always go 60
Well, Redline 20W-50 has a higher HTHS (6.1) than Redline 10W-60 (5.8)...
HTHS >3.0 for the win.
Look at the graph below and compare it to the wear graph shown in the article. See the similarity on ring wear as a function of HTHS. The hot running ring pack area doesn't seem to like low HTHS oil.
Look at the graph below and compare it to the wear graph shown in the article. See the similarity on ring wear as a function of HTHS. The hot running ring pack area doesn't seem to like low HTHS oil.
... when you happen to be running a long-ago engine at a sump temperature of 130°C.
And with oil at 100-110 C it would probably make the wear inflection around 2.8 cP like the second graph. As said, I go for HTHS >3.0 and sleep better, why run on the edge of possible increased wear all the time ?
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I've mixed SAE 50 with 15W40 50/50 to arrive at the same HTHS at half the price. Ok if 20w50 is ok for the ambient.
I noticed a small fuel economy hit vs 15w40 in a LML Duramax. It's all deleted now, runs cooler, the oil stays clean and fuel economy improved 25%.
I see people with BMW and audi that claim to be running these temperatures right on this site...
Hence the importance of using motor oils that are approved, licensed and certified for the given engine.
Plenty of people are having chain issues with the OEM spec'd oil and change interval. Plenty. Not to mention a rash of low tension piston rings that fail to seal, along with clogged piston oil drain holes.
I like thick oils but I think that top graph was from 1950. Can you find the source?
I know it wasn't that old. Think it was a paper out of Asia by some PhDs. Will have to do some searching to find it.
Update edit. Go down about 60% down on this website to the section "Which HTHS parameter is safer for the engine?" Looks like a Toyota R&D paper done in 1997. I think I have the paper on one of my computers ... would have to look. You might be able to find the report PFD on the 'net somewhere.
https://rallystore.ru/en/klassifikaciya-i-markirovka-motornogo-masla-po-vyazkosti-sae-hths--.html
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Thanks. Definitely looks Russian in origin; what year, who knows. Anyway thanks for the post.
It's shown in that link I gave that it's origin was a Toyota R&D study in 1997. The Russian website is just refering to the data and showing figures from the study.
Thanks again, I see the reference to the Toyota work. Quite the article, written in English with graph labels in Russian, posted in a Russian website, referencing a 24 year old Japanese study.
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