In a similar vein, with regards to thinner oils... My 2017 Hyundai Santa Fe Sport 2.0T has a TSB recommending 5W40 oil for years 2013-2017 "for best engine protection". "Even though it shows 5w30 on the oil fill cap". Their words. Not saying this is the same as the xw20 vs xw30 discussion, however if the thinner oil was getting the job done, they wouldn't retro spec a heavier weight.
Why does xw20 and xw30 show essentially the same/similar UOA but people blame cafe?
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This is exactly what I was talking about in my post. He just went 2 rounds with the ghost of Mike Tyson. Some people are so invested in a particular viewpoint, that, when coupled with the lack of will or ability to properly understand a counter-point, they immediately misconstrue it as an attack.
You brought up a great example with Ford and the Coyote and the BOSS 302. They did the same thing with the Track Pack version of the GT, spec'd 5w-50 for the same engine that spec'd 5w-20 in the "regular" GT.
FCA spec's 0w-40 in the 6.4L and 6.2L but 5w-20 in the 5.7L. The 6.4's (and especially the 6.2L) have higher power density and, being lower production, won't have much impact on CAFE. But construction-wise, the engines are all very similar and the 6.4L and 5.7L have the same clearances.
The paper we discussed from Honda years ago where they talked about the push to thinner oils resulting in more focus on additives that target increased operation in boundary/mixed vs hydrodynamic where you are working to control/limit wear, something not required in hydrodynamic, is another example. That was for 0w-12 and 0w-8 IIRC, with HTHS dropping below 2. As long as the wear rate was sufficiently controlled, it was acceptable (I believe they actually used the word acceptable in the paper) because it wasn't perceptible to the end user and still allowed the engine to achieve an appropriate lifespan. Of course one of the other issues was Noack that was wickedly high and an exception required to be made, but that's beyond the scope of this discussion.
Some screenshots from an SwRI research paper:
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Great post!
And another excellent post. UOA and engine tear downs can tell two totally different stories. I'd rather believe the tear down story for determining engine wear. I do believe a UOA has value, fuel dilution, how well an air filter is working, how long oil can go, along with a few other benefits. However anyone who thinks they determine engine wear or condition is wrong, sorry. But hey this is Bitog, and people will believe what they want to believe.
Hmm, OK, but what if you drive your underpowered four cylinder SUV like you're on a track? Then what oil do you use? lol.
I would imagine two things
1) 5,000 mile oil changes. [you took care of the vehicle]
2) The operation style and load.
Correct.
How long do you keep your toys?
Yes, another great post.
Table 2 was most interesting to me.
All the wear areas were generally worse off after a cold start (I believe this is defined as 75F), while towing a trailer and using the Start-Stop function while driving. Note that overall the wear was less under WOT and higher RPM when the oil is the hottest (and thinnest).
Also mentioned is high wear from cavitation (and not specifically the oil pump) and that it lessenes as the oil viscosity decreases. I wonder if it is this issue in a cold start. We know that as oil viscosity increases so does wear from aeration, Morgan et al. Eric Schneider showed how wear slowly decreases over the first 15-20 minutes of engine running after a 75F start up. People argue that it has nothing to do with thick cooler oil not being able to lubricate as well. Eric artificially lowered only the oil temperature of these engines while still running the water temperature the same and showed that the wear was at the same level as when the engine was warming up the first time at that oil temperature. To me this indicates that “it’s due to the engine parts not fitting correctly yet” has little or nothing to do with the early engine wear rate at 75F start up. Oil lubricates better when it warms and thins at the operating temperature.
Note also the friction data indicating less engine friction as the oil grade was decreased. But then it started back up when using the 8 grade oil, an indication the wear was increasing, but only with the thinnest of oils.
The oils are often not fully formulated in these tests. I feel that they do this so as not to start a battle amongst oil brands. How valuable is data from an oil not fully formulated???
And look at the Start-Stop wear. Do any of our politicians ever do any research before they make these mandates??
Just to mention a few points...in my quest to advocate thinner oil use.
ali
PS: "How long do you keep your toys?"
It varies. In general I treat them as if I will keep them forever. I only sold the Enzo because we were uncomfortable driving it. It was worth too much. So after 15 years we traded it in on something much less valuable.
Table 2 was most interesting to me.
All the wear areas were generally worse off after a cold start (I believe this is defined as 75F), while towing a trailer and using the Start-Stop function while driving. Note that overall the wear was less under WOT and higher RPM when the oil is the hottest (and thinnest).
Also mentioned is high wear from cavitation (and not specifically the oil pump) and that it lessenes as the oil viscosity decreases. I wonder if it is this issue in a cold start. We know that as oil viscosity increases so does wear from aeration, Morgan et al. Eric Schneider showed how wear slowly decreases over the first 15-20 minutes of engine running after a 75F start up. People argue that it has nothing to do with thick cooler oil not being able to lubricate as well. Eric artificially lowered only the oil temperature of these engines while still running the water temperature the same and showed that the wear was at the same level as when the engine was warming up the first time at that oil temperature. To me this indicates that “it’s due to the engine parts not fitting correctly yet” has little or nothing to do with the early engine wear rate at 75F start up. Oil lubricates better when it warms and thins at the operating temperature.
Note also the friction data indicating less engine friction as the oil grade was decreased. But then it started back up when using the 8 grade oil, an indication the wear was increasing, but only with the thinnest of oils.
The oils are often not fully formulated in these tests. I feel that they do this so as not to start a battle amongst oil brands. How valuable is data from an oil not fully formulated???
And look at the Start-Stop wear. Do any of our politicians ever do any research before they make these mandates??
Just to mention a few points...in my quest to advocate thinner oil use.
ali
PS: "How long do you keep your toys?"
It varies. In general I treat them as if I will keep them forever. I only sold the Enzo because we were uncomfortable driving it. It was worth too much. So after 15 years we traded it in on something much less valuable.
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I have some dear friends with Ferraris and the sad thing about them is they are so valuable , it is scary to drive them. My friends ask me if I want to drive and I say Nope. Too pricey. and that is the same reason I don't do flying. Call me a sissy and I will accept it..
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A lot of it has to do with the temperature at which additives become active. This is another issue with start/stop.
I remember a study done ages ago that showed that running an engine below 180F coolant temp significantly increased wear. Above 180F, the decrease in wear was basically insignificant, but you started losing performance because of timing needing to be pulled. Now, this was for old school port-injected pushrod mills, so may not be applicable to every situation (the performance stuff).
Less friction in the bearings, more friction in the valvetrain with the thinner oils.
It breaks down as:
0w-8 - least friction in the bearings, most friction in the piston assembly and valvetrain
0w-16 - lower friction in the bearings, less friction in the piston assembly, more friction in the valvetrain
0w-20 - low friction in the valvetrain, more friction in the piston assembly and bearings
0w-30 - least friction in the valvetrain, more friction in the piston assembly and bearings
Seems like an xW-20 is the sweet spot in this particular engine. The friction in the piston assembly goes from oil related friction (like in the bearings) with the 0w-30 to actual sliding friction (wear) with the 0w-8. Since the valvetrain doesn't operate in hydrodynamic, just boundary, wear, and friction, increases there as viscosity drops.
In the comparison of the 5w-30 and 0w-16, both oils were fully formulated and using a Dexos1 Gen 2 additive package.
Yep, which makes sense when you figure how temperature and additive activation play-in to this.
They said they used the same formulated oil (same additives) but in two different viscosities for the wear testing - it's not about testing Oil A vs Oil B, and if they used different oil formulations it would skew the viscosity effect. What this testing shows is that the viscosity (film thickness/MOFT) is the main factor in keeping moving parts separated - the backbone of tribology from day one. Yes, this shows 16 vs 30, but if the same formulated oil in 20 was also tested it would fall in between the 16 and 30. Figure 5 shows running 0W-8 in an engine not specifically designed for it would be pretty risky.
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Modern oils have anti-foaming additives which basically prevent excessive aeration, so I don't really buy in to aeration in thicker oils causing wear. If that was the case, then the SWRI test data in Figures 6 and 7 would show the opposite of what it does. And when oil is near or at full operating temperature, regardless of the viscosity, it's all pretty low viscosity so aeration is way less likely when the oil is hot. If there is any wear from aeration, it's only during the warm-up period.
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Not to mention that many motorcycles are running on thick diesel oil and turning way more rpm and for longer periods, than a street engine. If foaming/aeration was an issue, it would show up there.
My original Honda 750 FOUR had an external oil tank, these minimize aeration. What do modern motorcycles use? Are they, some of them, still on wet sumps? Incidentally I used Castrol 20W50 back then - but I did live in Florida at the time.
Ali
Ali
Same here, 99% of my driving conditions are severe, lead footed, and aggressive, and once my engine is started it runs at operating temperature for 8-10 hours with multiple pulls to redline daily. If you drive like that then you'd probably be safer with a grade or two higher.
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My Can-Am 1000R spins to the moon most of the time (1,000cc V-twin w/CVT) and it has a shared sump. I run M1 0w-40 in it, it calls for an xw-40.
I see the opposite on this site - pages and pages of people pushing thin oil...and one or 2 post pro thick. It's enough to keep the thread going on and on. You don't see a first post about thick oil, it's always about thin oil.
My two motorcycles (both runnibg 10W-40 and both ~10,500 redline) have a glass oil level window in the crankcase so you can see oil when off the bike while the engine is running. I've looked at the oil when cold after a start-up and there might be a few air bubbles in it, but nothing to be worry about.
After it's warned up there is zero signs of aeration, even after revving the engine up and down for awhile. The oil level also goes down some every time the engine is revved up pretty good, as expected.
The Honda 750 was pretty unique to have a dry sump even back in those days . Only bikes made today that I can think about that have a dry sump are some Harleys. I can't think of one Asian bike made today that has a dry sump. A wet sump is simpler, and it gives the bile a more balance and lower CG.
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