Interesting article on fuel economy oils and HD engines:
http://www.iantaylor.org.uk/papers/SAE2000012056.pdf
http://www.iantaylor.org.uk/papers/SAE2000012056.pdf
HD Engine Lubricant sensitivities
- Thread starter reyjay1
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OK, good read, the conclusion is that use of fuel efficient lubricants can save 2 - 6% in operating costs. But, it continues, the potential loss of "durability" must be considered (before) using these lubricants.
Well then, what holds the greater overall economic cost to the owner? Probably engine wear. So...don't use the fuel efficient lubes?!!??
Well then, what holds the greater overall economic cost to the owner? Probably engine wear. So...don't use the fuel efficient lubes?!!??
yes, that is the conclusion I get in high load engine, notice the first part where it differentiates between this and low load, PC engines.
Then couple this with the two other papers i posted here:
http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=1;t=011536;p=2
I think this just goes a long way to explaining the state of oil formulation today, it is not just as simple as thick/thin is better. You have to be asking yourself, "better at what?"
Just stirring the pot .... and passing on stuff i found, maybe this has been done here before.
Then couple this with the two other papers i posted here:
http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=1;t=011536;p=2
I think this just goes a long way to explaining the state of oil formulation today, it is not just as simple as thick/thin is better. You have to be asking yourself, "better at what?"
Just stirring the pot .... and passing on stuff i found, maybe this has been done here before.
ps. in the last of those second two papers I think, notice that the viscosity of the 5-20 oil remains fairly constant across shear rates, but is always lower than the 0-40 or 15-40, whereas the 15-40 loses some viscosity at higher shear rates but never gets down to the 5-20 level, whereas the 0-40 loses viscosity to near 5-20 levels at high shear rates. if you can handle a lower viscosity for the application it looks like the 5-20 might be fine, but if the 5-20 is too low and transitions to boundary conditions more often the 15-40 could provide real benefit.
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This might be a bit off-topic but it is a e-mail that I received from a Russian friend who has formulated oils longer than I've been on the planet. In a recent discussion he spoke of viscosity, HT/HS, and wear. I have deleted out the personal information and present only his views about motor oil. Please keep in mind that English is not his first language. His letter follows:
-SOM-
As to your oil: The viscosity at 150°C (HTHS) is notoriously difficult to measure. It is a rotten English design. The lab people hate it. You have to reference it in the morning and in the evening and the next day you won't get the same result. 3,4 could therefore be the required 3,5. It is true that this test has been established to protect the cams. But the cars are different. Some have been designed to live with 2,9 others that are prone to wear need 3,5. At least that is what the guys who write the specifications want. I doubt whether they know what they need. Ford have designed their engines so that they can live with 2,9 oils. You can do that by broadening the contact surface and by lowering the specific pressure. Others like VW who tighten the contact area will cause higher requirements on the wear performance of the oil. That is the basis of all the stupid VW specifications with the .01 suffix.
Normally the engine builders just start designing and building their engines. Later, shortly before selling them, they find that they need a special oil because they have built in some hardware deficiency that they cannot cure immediately but they pray to God that a special oil could do it. That is the point where I was usually called in. Hectic started, the management got mad and holy oaths were made that with the next development the oil will be considered as a valuable and most important spare part and the lube oil formulator will be treated as a partner. That is the theory. In practice it never worked. I wait here to be called in to save the next transmission box that works nicely on the screen but not in practice.
Oils with a good wear protection can be low in viscosity. You check that with the engine tests. Viscosity is not the dominant factor when formulating engine oils with good wear performance. The trend of the engine oils to lower viscometrics is still going on. The formulator has to take this into account. You cannot tell the wear performance difference by measuring the viscosities. Wear tests are expensive, mostly full blown fired engine tests. Other wear tests on the market are totally inappropriate.
If you are afraid of the quality of your oil the only advice I have is to buy a good brand. I know that smaller companies in Europe cheat with their claims. The big multinational companies, mostly with their origine in the USA have set up ethical company policies to which they strictly adhere. The control mechanisms to bring the correct OEM approved formulation into the market do exist in all these companies. Even if they are a bit more expensive because you pay for the brand, you can rely on their quality procedures. -EOM-
I find his views on wear and low viscosity interesting. It goes against the thicker=better view that I have had for too long.
-SOM-
As to your oil: The viscosity at 150°C (HTHS) is notoriously difficult to measure. It is a rotten English design. The lab people hate it. You have to reference it in the morning and in the evening and the next day you won't get the same result. 3,4 could therefore be the required 3,5. It is true that this test has been established to protect the cams. But the cars are different. Some have been designed to live with 2,9 others that are prone to wear need 3,5. At least that is what the guys who write the specifications want. I doubt whether they know what they need. Ford have designed their engines so that they can live with 2,9 oils. You can do that by broadening the contact surface and by lowering the specific pressure. Others like VW who tighten the contact area will cause higher requirements on the wear performance of the oil. That is the basis of all the stupid VW specifications with the .01 suffix.
Normally the engine builders just start designing and building their engines. Later, shortly before selling them, they find that they need a special oil because they have built in some hardware deficiency that they cannot cure immediately but they pray to God that a special oil could do it. That is the point where I was usually called in. Hectic started, the management got mad and holy oaths were made that with the next development the oil will be considered as a valuable and most important spare part and the lube oil formulator will be treated as a partner. That is the theory. In practice it never worked. I wait here to be called in to save the next transmission box that works nicely on the screen but not in practice.
Oils with a good wear protection can be low in viscosity. You check that with the engine tests. Viscosity is not the dominant factor when formulating engine oils with good wear performance. The trend of the engine oils to lower viscometrics is still going on. The formulator has to take this into account. You cannot tell the wear performance difference by measuring the viscosities. Wear tests are expensive, mostly full blown fired engine tests. Other wear tests on the market are totally inappropriate.
If you are afraid of the quality of your oil the only advice I have is to buy a good brand. I know that smaller companies in Europe cheat with their claims. The big multinational companies, mostly with their origine in the USA have set up ethical company policies to which they strictly adhere. The control mechanisms to bring the correct OEM approved formulation into the market do exist in all these companies. Even if they are a bit more expensive because you pay for the brand, you can rely on their quality procedures. -EOM-
I find his views on wear and low viscosity interesting. It goes against the thicker=better view that I have had for too long.
Good read. Thanks for sharing your friend's words with us.
I like when he says... "Normally the engine builders just start designing and building their engines. Later, shortly before selling them, they find that they need a special oil because they have built in some hardware deficiency that they cannot cure immediately but they pray to God that a special oil could do it."
This guy is brilliant. Can you get him to come aboard here? He'd be a great member, if he had the time to do it...
Dan
I like when he says... "Normally the engine builders just start designing and building their engines. Later, shortly before selling them, they find that they need a special oil because they have built in some hardware deficiency that they cannot cure immediately but they pray to God that a special oil could do it."
This guy is brilliant. Can you get him to come aboard here? He'd be a great member, if he had the time to do it...
Dan
Interesting articles, and captions.
I think some emerging thought on shear stability concerns the use of single grade oils. Someone put an article of airplane use of monogrades that indicated the superior-like quality of their stability, even (better) at the temp extremes contrary to what one would expect. I've been waiting for someone to send in a UOA on the new Amsoil SAE30, which Amsoil is labeling a 10W-30 (because of the visc range inherent to it).
Lets see, oils started with single grades, then multigrades, now wide range multigrades, and now a re-look at monogrades! Truly, "what goes around..."
I think some emerging thought on shear stability concerns the use of single grade oils. Someone put an article of airplane use of monogrades that indicated the superior-like quality of their stability, even (better) at the temp extremes contrary to what one would expect. I've been waiting for someone to send in a UOA on the new Amsoil SAE30, which Amsoil is labeling a 10W-30 (because of the visc range inherent to it).
Lets see, oils started with single grades, then multigrades, now wide range multigrades, and now a re-look at monogrades! Truly, "what goes around..."
Edit: I guess this should have a
Interesting to see the air resistance losses:
20km/h: .63KW
60km/h: 17.01KW (~23hp)
I knew air resistance losses weren't linear as speed increases but that's dramatic! And 60km/h is only ~35mph.
Interesting to see the air resistance losses:
20km/h: .63KW
60km/h: 17.01KW (~23hp)
I knew air resistance losses weren't linear as speed increases but that's dramatic! And 60km/h is only ~35mph.
MolaKule
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Yep, been there, one that!
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