0W-8 is here: JASO GLV-1

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They bench-tested the oils in a Toyota Prius/Prius Prime 2ZR-FXE engine (firing engine) to measure the fuel-economy improvement. They also dyno-tested the oils in a Nissan Rogue Sport MR20DD engine (motoring engine) running in a real vehicle. "SAE 0W-8 high-moly oil demonstrated 0.5% fuel economy improvement over SAE 0W-16 organic friction modifier (OFM) oil." How much of the improvement is coming from the SAE 8 and how much is coming from the high moly? It's obvious this is an apples to oranges comparison. We don't even know if SAE 0W-8 actually made the fuel economy worse by entering into the elastohydrodynamic-lubrication region in the bearings and increasing the boundary-lubrication friction in the cylinders and valvetrain. Obviously more transparency is needed, which is not being provided.
 
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Originally Posted by Gokhan
We don't even know if SAE 0W-8 actually made the fuel economy worse by entering into the elastohydrodynamic-lubrication region in the bearings and increasing the boundary-lubrication friction in the cylinders and valvetrain. Obviously more transparency is needed, which is not being provided.


Agreed ... and it would be interesting to see wear numbers along with the testing also. Could be that the high Moly is doing most of the work as the viscosity becomes lower and lower, and more metal-to-metal contact is increased from the diminishing MOFT. It was discussed many moons ago that these super thin viscosity oils will have to rely heavily on anti-friction/anti-wear additives because the MOFT his going to suffer and give way less metal-to-metal contact prevention headroom.
 
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Arizona
Originally Posted by ZeeOSix
Originally Posted by Gokhan
We don't even know if SAE 0W-8 actually made the fuel economy worse by entering into the elastohydrodynamic-lubrication region in the bearings and increasing the boundary-lubrication friction in the cylinders and valvetrain. Obviously more transparency is needed, which is not being provided.
Agreed ... and it would be interesting to see wear numbers along with the testing also. Could be that the high Moly is doing most of the work as the viscosity becomes lower and lower, and more metal-to-metal contact is increased from the diminishing MOFT. It was discussed many moons ago that these super thin viscosity oils will have to rely heavily on anti-friction/anti-wear additives because the MOFT his going to suffer and give way less metal-to-metal contact prevention headroom.
Indeed. This has been a bother to me for some time: Multiple technologies are shifted at once, but results are presented as if to show that viscosity doesn't matter other than as a way to alter mpg. They may or may not be, but no one is generating or presenting the data to demonstrate that.
 

Gokhan

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Gokhan

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Originally Posted by ka9mnx
Neither link loaded in my browser?
They are PDF files. If your browser cannot open them directly, try right-clicking on the link and saving the file.
 
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And here I was just thinking about how I've never seen 0W-16 in the wild.

I figured this day would come.

So now when 0W-8 shears to a 0W-5 with fuel dilution from DI...
 
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Silicon Valley
They bench test this oil for a hybrid, so the low rpm low torque scenario is addressed with an electric motor. I'd say for that application it is SAFE.

Don't try this in your high torque high displacement engine without hybrid though. Stay with 0w20 unless manufacturer approves, likely with a variable flow oil pump.
 
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EU
Bottomline for me is what I told you some time ago: When replacing modern grades - like 0W-8 by 0W-16 to roll this back - one generally wouldn't know what to expect regarding wear. Too many areas in an engine where our traditionals are worthless anyway, especially dealing with just visco grades, then too little knowledge what get's lost over an upgrade (downgrade in additives you'd have to expect obviously).
At least all should become clearer for those compared against the standard case of the pivotal main battle oils 0W-20 (+ 5W-20) and their usual variables like different VM strategies meaning that a high VI can come with a thicker base oil, or other qualities letting a 5W-30 hardly upgrade anything useful over the 0W-20.
 
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Would love to know what this new BYD hybrid relies on for its 43.05% efficiency. We'll probably see their nailable Han but never receive the hybrid.
 
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