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Should recommend oil grades based on geo region …
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HPL SAE 40 PCMO
- Thread starter Hohn
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What does that have to do with the rate of warm-up though? The assertion was that thinner oil got to operating temperature quicker, and that's what is being contested.
With heavier oil, you have more fluid friction, which is going to result in a higher rate of fuel burn, which is going to result in more heat being generated, which is going to be rejected into the coolant and the lubricant. On top of that, there's the heat generated by the fluid friction itself as well as the heat generated by the acts of shearing forces on the fluid, like in all of the journal bearings. This is all additive.
All of this slows as the temperature increases and the fluid thins and the gap between the heavier fluid and the thinner fluid closes.
If you were to plot this process (and @Shannow provided some graphs in that thread I linked, with values in watts) for the same warm-up process for two identical engines with different grades of oil, the one with the heavier oil would be consuming more fuel, thus generating more heat and that heat is going into the coolant and the oil, as he notes in that thread. Ergo, that engine is "warming up" quicker, the obvious penalty being fuel efficiency.
Yes, there are multiple things going on and multiple heat transfer processes happening during an engine warm-up, and the design of the engine also plays a role, especially on engines that have a coolant to oil heat exchanger which warms up the oil as the coolant warms up. I never saw any noticeable oil warm-up or oil operating temperature difference between running 5W-20 and 5W-30 in the Coyote - no surprise. Maybe if I ran 0W-20 compared to 20W-50 I might see something but maybe not with the coolant to oil heat exchanger and with the stock on-board sensors. Would have to rig up some kind of test with more instrumentation. Not anything important enough to put effort into.
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I have observed warm up temperatures of coolant and oil on my 2018 Subaru Forester, which does not have an oil cooler. Running a 20 or 30 grade oil, I am not able to exceed a 50 degree difference coolant to oil during warmup. Running a 40 grade oil, I am able to reach a 55 degree difference pretty easily during warmup. I understand this is only my observation and not a proper controlled test.
I didn’t notice anybody mention the 4.2 cP HTHS and 14.3 cSt viscosities, but it’s relevant so there it is. I’m glad that Hohn is experimenting and sharing the outcomes. More hard data would be nice, like oil temperatures and pressures, drain plug magnet residue, and volatility. I suspect that all of them are unavailable.
The VOA of the SAE 40 is ready.
Nothing really jumps out other than the trace aluminum that was mentioned earlier that is residue from the catalyst. The Mg/Ca ratio and levels are essentially identical to the 15w-40, as are Zn and P levels. The 10ppm silicon from the antifoam package is pretty typical of the HPL PCMOs.
Perhaps the virgin oxidation is slightly higher as a result of the extra esters used to thicken the GTL up a bit. I think that in general the heavier grade PCMO line gets more AN and less ester so they seem to run lower on virgin oxidation vs the low 30s that the 5w-30 PCMO runs, for example. Recall the baseline (not virgin) oxidation level on my 15w-40 PCMO was 23 with only 100 miles on it. And the prior oil was HPL 5w-30, so we know that the residual oil on the baseline 15w-40 should have *raised* oxidation from whatever the true 15w-40 VOA is. So the 15w-40 VOA is almost certainly around 20. Which would make the 26 of the SAE 40 sort of a “come full circle” with higher ester content than the 15w-40. Given the very high density of this SAE 40 and the lower pour point, it reasonable to infer significantly more ester in the monograde than in the 15w-40.
The TBN coming in a 12.2 is a bit low, but within the normal batch to batch variation I would expect. That’s a critical bit of info to have because I think it matters if you’re losing 3 points or 4 points in 5k miles or so. We’re grabbing the short end of a very long stick with our extrapolations from some of this data, so error is magnified.
Since I sent in both samples at the same time, I’m guessing we’ll have our in-sump baseline for this oil pretty soon, probably later today.
Then we’ll have the used oil analysis for the 15w-40 immediately before draining, the SAE 40 VOA, and the baseline SAE 40 in sump. Not only will we see what the effect of carryover residual oil is, but we’ll know exactly the composition of that carryover as well. Should be some useful insight.
Nothing really jumps out other than the trace aluminum that was mentioned earlier that is residue from the catalyst. The Mg/Ca ratio and levels are essentially identical to the 15w-40, as are Zn and P levels. The 10ppm silicon from the antifoam package is pretty typical of the HPL PCMOs.
Perhaps the virgin oxidation is slightly higher as a result of the extra esters used to thicken the GTL up a bit. I think that in general the heavier grade PCMO line gets more AN and less ester so they seem to run lower on virgin oxidation vs the low 30s that the 5w-30 PCMO runs, for example. Recall the baseline (not virgin) oxidation level on my 15w-40 PCMO was 23 with only 100 miles on it. And the prior oil was HPL 5w-30, so we know that the residual oil on the baseline 15w-40 should have *raised* oxidation from whatever the true 15w-40 VOA is. So the 15w-40 VOA is almost certainly around 20. Which would make the 26 of the SAE 40 sort of a “come full circle” with higher ester content than the 15w-40. Given the very high density of this SAE 40 and the lower pour point, it reasonable to infer significantly more ester in the monograde than in the 15w-40.
The TBN coming in a 12.2 is a bit low, but within the normal batch to batch variation I would expect. That’s a critical bit of info to have because I think it matters if you’re losing 3 points or 4 points in 5k miles or so. We’re grabbing the short end of a very long stick with our extrapolations from some of this data, so error is magnified.
Since I sent in both samples at the same time, I’m guessing we’ll have our in-sump baseline for this oil pretty soon, probably later today.
Then we’ll have the used oil analysis for the 15w-40 immediately before draining, the SAE 40 VOA, and the baseline SAE 40 in sump. Not only will we see what the effect of carryover residual oil is, but we’ll know exactly the composition of that carryover as well. Should be some useful insight.
Update: the true baseline in the crankcase. I’ll quote the VOA below so it’s handy for comparison.
1.2% dilution at 8 miles! And already we’re down nearly a full point in KV100 and a half point in TBN.
This is a good time to remind ourselves not to make big conclusions from small differences that are within the lab noise, especially on confounding data point here like the fall in oxidation and the rise in Ca. One wouldn’t think that residue with 25 oxidation would drop to 22 when mixed with 26. Nor would one think that 1044 Ca residue mixes with 1198 to produce 1353.
With that variation in mind, it changes how I view the prior results on the 15w-40 somewhat. Without a clean baseline run on the 15w-40 in this engine, we have to think that the prior drain ALSO carried over at least 1% dilution from the prior Valvoline Restore and Protect. Not to mention that It probably started out more like 11 even on the TBN since the Valvoline Restore and Protect residue was down in the low 3.x range. And the KV100 of the 15w-40 probably also in the low 13s and barely even a 40 grade. Recall from my GX460 that the baseline 15w-40 KV100 was also 13.2– a low 40 grade.
So my primary takeaways from this trio of drain/VOA/Baseline samples is:
— Lab results vary, don’t make a big deal of small differences
— Carryover has real effects. A baseline FROM THE SUMP is critical or you have no real way of interpreting your UOA.
— You might need to cheat significantly higher on fill KV100 or HTHS if you have minimums for each that you want to hit. For example, it’s all but a given that these 40 grades both started out with KV100s in the 13 flat range and HTHS of about 3.8. If I want to have something like 14.5 Kv100 on the baseline or an HTHS of 4.2 or 4.4 in the sump, I’m going to have to mix in a bit of 50 grade to bump it up and offset the contaminating effect of the carryover residue.
1.2% dilution at 8 miles! And already we’re down nearly a full point in KV100 and a half point in TBN.
This is a good time to remind ourselves not to make big conclusions from small differences that are within the lab noise, especially on confounding data point here like the fall in oxidation and the rise in Ca. One wouldn’t think that residue with 25 oxidation would drop to 22 when mixed with 26. Nor would one think that 1044 Ca residue mixes with 1198 to produce 1353.
With that variation in mind, it changes how I view the prior results on the 15w-40 somewhat. Without a clean baseline run on the 15w-40 in this engine, we have to think that the prior drain ALSO carried over at least 1% dilution from the prior Valvoline Restore and Protect. Not to mention that It probably started out more like 11 even on the TBN since the Valvoline Restore and Protect residue was down in the low 3.x range. And the KV100 of the 15w-40 probably also in the low 13s and barely even a 40 grade. Recall from my GX460 that the baseline 15w-40 KV100 was also 13.2– a low 40 grade.
So my primary takeaways from this trio of drain/VOA/Baseline samples is:
— Lab results vary, don’t make a big deal of small differences
— Carryover has real effects. A baseline FROM THE SUMP is critical or you have no real way of interpreting your UOA.
— You might need to cheat significantly higher on fill KV100 or HTHS if you have minimums for each that you want to hit. For example, it’s all but a given that these 40 grades both started out with KV100s in the 13 flat range and HTHS of about 3.8. If I want to have something like 14.5 Kv100 on the baseline or an HTHS of 4.2 or 4.4 in the sump, I’m going to have to mix in a bit of 50 grade to bump it up and offset the contaminating effect of the carryover residue.
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Not straight 40, but probably would have made sense to recommend it over the SAE 30. 79-80 Honda CBX1000 service manual:
Mostly should be using 20W-50 yet they recommend an SAE 30 as alternative. 6 cylinder air cooled bike. Incredibly hot.
Norton Commando says SAE40 is OK to use: https://www.classicbike.biz/Norton/Repair/70up_Commando/70upCommando.pdf
Sure, in a Norton it probably drops the leakage under a quart a week
Don't think using Norton for guidance is well advised.
I'm just mentioning that some manufacturer has stated it's OK for use. You said that no manufacturer has.
The way that manual is written, you could use SAE 30 even if the ambient temperature was 110F in Vegas (they don't show a max temp for its use) ... yet that would be the last thing I'd do. It also shows don't use SAE 30 below 60F, so that engine was sensitive to cold start oil viscosity.
The broader point here is that owner’s manual recommendations are irrelevant to this discussion.
As I’ve said before, not manual can recommend a monograde 40 without allowing all the cheap junk with 40 year old specs to be used.
And the oil in question here is a world class formulation that just happens to be an SAE 40.
As I’ve said before, not manual can recommend a monograde 40 without allowing all the cheap junk with 40 year old specs to be used.
And the oil in question here is a world class formulation that just happens to be an SAE 40.
I can agree with that. Clearly what you're doing is working for your use case so why not?
I expected the mpg with the monograde to eventually recover from the initial low values caused by lots of city trips (and operation by my wife) early in the OCI.
But I did not expect that it would recover to the long term average so fast.
As of this morning, the SAE 40 is actually averaging OVER 29.0 for the OCI. That means it has not only surpassed what the 15w-40 gave for mpg for its total interval, but also surpassed the 29.0 mark set by Valvoline Restore and Protect 5w-30. Note, we haven't even gotten into warm summer weather yet and I'm right now parking outside and starting the car in temps in the 40s most mornings. This strongly suggests to me that the SAE40 is on pace to be the best MPG oil I've used in this car to date, and perhaps by a pretty significant amount.
But I did not expect that it would recover to the long term average so fast.
As of this morning, the SAE 40 is actually averaging OVER 29.0 for the OCI. That means it has not only surpassed what the 15w-40 gave for mpg for its total interval, but also surpassed the 29.0 mark set by Valvoline Restore and Protect 5w-30. Note, we haven't even gotten into warm summer weather yet and I'm right now parking outside and starting the car in temps in the 40s most mornings. This strongly suggests to me that the SAE40 is on pace to be the best MPG oil I've used in this car to date, and perhaps by a pretty significant amount.
Summer blend fuel?
I was wondering about the same thing. But I don’t know when they switch and how to know if they did.
Patman
Staff member
I think summer blend doesn’t come out for a few more weeks
