Not for me.It seems crazy, but to get 1 mpg more is a great incentive!
Not for me.It seems crazy, but to get 1 mpg more is a great incentive!
Here's the secret button to quote someone, lol.Can someone write a paper on how to multiquote I go crosseyed with his manual copy no quotes method.
And that test wasn't performed on a twin turbo DI engine making just under 130HP/L.In an SAE paper I presented earlier: ( https://bobistheoilguy.com/forums/t...-5-were-unacceptable-for-wear-control.364170/ )
wear was steady above a HTHS of 2.5 but only doubled when the HTHS dropped to 1.8. I am using an oil at 1.6. That study used unrealistic stresses and non fully formulated SG mineral based oils. The engine was lop-sided and the oil temperature was steadily kept at 150C in the feed lines. So with my situation I should be safe in my opinion.
I mean, it often is, if we are being honest.Maybe we should entirely eliminate the UOA section of this web site since people are given advice on a single UOA. The advise could be wholly misleading and totally wrong based on a single test.
I'm not condoning nor condemning your experiment. This is your equipment, you paid for it, you are clearly aware of the risk and are in possession of sufficient means that repair or replacement is not going to cause you undue burden or even inconvenience.I say again. I am an experimenter and present my data. Some will get some benefit from it. I also have experimented with other things. Like various types of grass here in Florida and presented the data to Florida pesticide applicators during courses I teach for them. I have done experiments on mulch for the garden. I have made various changes to scuba diving gear, model airplanes, electronics and others areas of interest to me. I have had intercourse with manufacturers.
People can learn from these things or throw stones at me. I learned something when I was reviewing an article for publication in a medical journal. Many reviewers said it was worthless for a bunch of reasons and that it should not be published. I was one of them. The article was published anyway because it had a very very important lesson in it that was part of the story, and not at first obvious.
One test vehicle showing evidence that a modern 5 grade oil can be used in a lower stressed SUV may be valuable to some. A person who chooses to try a 20 grade oil in such a truck specifying a 30 grade oil may feel more comfortable doing so. Would it not be beneficial to gain just one piece of knowledge, if you look for it, rather than use all your energy to find fault?
ali
Yes, varying rod loads certainly does have an effect on the bearing's MOFT. Running WOT and max HP also reduces the MOFT at certain rod angles to the crankshaft. Been graphs posted many times showing how MOFT changes as the bearing rotates and the loads in the rods. "Lugging" the engine at low RPM and high throttle openings is a bad thing and can result in less MOFT because the engine RPM is low and the rod force into the bearing is high. Example of that would be heavy towing up big hill with the throttle very wide open, but lugging the engine at a lower RPM at the same time (standard transmission of course, since automatics will down shift as needed).One point that also hasn’t been discussed is the margin to catastrophic bearing failure is also reduced for knock events. How well tuned are these? How much knock is required and how often to damage a bearing, but not pistons and such?
I’d hate to wipe a bearing because of a tank of bad gas that wouldn’t damage the engine otherwise and would not have happened if a proper viscosity was used. Correct me if I’m wrong, but the tribo layer isn’t meant to handle blunt force trauma.
As viscosity is temperature dependent it might be good to review where things in an engine heat up the oil. Many would have you believe it is in the bearings that should "light up" from the heat of normal use. It is not the case. Under no load there is very little temperature rise of the motor oil as it goes through the journal bearings. Under average loads oil actually heats up something like 10 - 15 % just by friction in the pump and oil ways particularly when the oil is more viscous. 70 - 80 percent of the heat gain is from the piston / cylinder areas. Journal bearing do not always, magically heat up to 304F (HTHS temp) and then stay there. It is amazing to me just how much hotter an engine runs due to the internal friction of thicker oils.
The oil heats up in journal bearings due to the oil shearing from the rotation speed of the bearing. So increased engine RPM is the biggest factor in the oil temperature increasing in the sump. Hold the engine load constant and vary the RPM and there's a direct correlation between bearing speed and oil temperature - all other factors held constant. There's a reason that the HTHS viscosity at 150C was invented and put into SAE J300 ... it's been discussed many times.As viscosity is temperature dependent it might be good to review where things in an engine heat up the oil. Many would have you believe it is in the bearings that should "light up" from the heat of normal use. It is not the case. Under no load there is very little temperature rise of the motor oil as it goes through the journal bearings. Under average loads oil actually heats up something like 10 - 15 % just by friction in the pump and oil ways particularly when the oil is more viscous. 70 - 80 percent of the heat gain is from the piston / cylinder areas. Journal bearing do not always, magically heat up to 304F (HTHS temp) and then stay there. It is amazing to me just how much hotter an engine runs due to the internal friction of thicker oils.
The turbo bearings will be hot.As viscosity is temperature dependent it might be good to review where things in an engine heat up the oil. Many would have you believe it is in the bearings that should "light up" from the heat of normal use. It is not the case. Under no load there is very little temperature rise of the motor oil as it goes through the journal bearings. Under average loads oil actually heats up something like 10 - 15 % just by friction in the pump and oil ways particularly when the oil is more viscous. 70 - 80 percent of the heat gain is from the piston / cylinder areas. Journal bearing do not always, magically heat up to 304F (HTHS temp) and then stay there. It is amazing to me just how much hotter an engine runs due to the internal friction of thicker oils.
Yep and last time I looked at Ecoboost engines (unless something has changed) they suffer from fuel dilution which an xW-30 in those engines is typically a mid-low xW-20 when it is changed. There is zero head room for dilution with a 0W-5 viscosity oil so this should get interesting very quickly...And that test wasn't performed on a twin turbo DI engine making just under 130HP/L.
Journal bearing oil temperature can get to the HTHS 150C if the RPM is high enough.Journal bearing do not always, magically heat up to 304F (HTHS temp) and then stay there.
You have some controlled oil HTHS viscosity vs engine RPM vs engine load test data that shows that the difference is so amazing?It is amazing to me just how much hotter an engine runs due to the internal friction of thicker oils.
Yeah, and it's the viscosity that always provides the smallest MOFT ... it's been mentioned many times that viscosity is directly related to MOFT with all other factors held constant.Here is a nice paper including viscosity and MOFT.
Oil Clearance and Engine Bearings [SubsTech]
www.substech.com
It includes 0w5 oil.
You also need to keep in mind that since 0W5 isn't a J300 grade, there's nothing defining it. There have been several examples posted on here in the past, one was actually a 0W-20, another a 0W-16...etc.Here is a nice paper including viscosity bearing clearance and MOFT.
Oil Clearance and Engine Bearings [SubsTech]
www.substech.com
It includes 0w5 10w30 and 10w60 oil. Granted it is a sales pitch for King Bearing but fairly recent paper.
When you reference the Taxi study, I assume you mean this one?I guess I like to provide opposing views. Here is another one from a 1 cylinder engine study, an SAE paper, briefly:
The results indicated that there was no relationship between the high temperature, high shear rate viscosity of multigrade oils and bearing demerits. The chemical composition of the engine lubricants appeared as a primary variable which overshadowed the viscometric considerations... It was possible to reduce the bearing protection provided by an SAE 30 oil to less than that of an SAE 5 oil by the selective substitution or elimination of the additive components.
Ergo a 5 grade oil can protect as well as a 30 grade (non formulated) oil when fully formulated. The 30 grade has the MOFT but the plain oil alone is only so good. The 5 grade oil with “insufficient MOFT” but fully formulated oil can protect just as good as the thicker oil. Also, the above charts and all are about MOFT. I do not see anything about bearing wear mentioned.
There were many instances of very high wear in cabs operated with the lowest viscosity oils but none in cabs with higher viscosity oils. Non-Newtonian oils appeared to provide slightly more protection than Newtonian oils of the same HTHS viscosity, and a higher quality adpack also appeared to provide benefits. However, these factors were secondary to the viscosity of the oil. HTHS viscosity was a better predictor of bearing wear performance than oil film thickness.