Originally Posted By: Shannow
Originally Posted By: JHZR2
To say CAFE is the only driver behind thin oils and the benefits they can offer is uninformed. Again, if there is copious data proving reduced longevity due to thinner oils, do share.
see, there's that strawman pile of failed engines argument again.
One does NOT have to point to failed engines as CAFE being reason for going to thinner oils...in the US CAFE market, and the Japanese (CO2/fuel efficiency) markets
The manufacturers clearly tell us WHY they are going to thinner oils...
as to the emasculation, the way that certain posters here maintain their argument it's like if they admitted why the OEMS are doing it, it would somehow make them less of a man.
As to changes in design...read any of the Honda Papers, read papers by bearing manufacturers like Mahle.
Viscosity (and stop start - clearly for economy/CO2) are driving the changes in bearing design and finish...the oils aren't in response to engineering, it's clearly the other way.
Fuel management and cooling management are the major drivers in engine longevity.
So no engine improvements of any of the types you mention, and then some, would have happened without CAFE?
Because as far as I can see, many if not most of the improvements offer benefit outside of that regime.
You're speculating that vendors wouldn't be pursuing lower viscosity oils as another compiled benefit without CAFE. I maintain that as substantially speculation.
I don't see the failed engine argument in ad of itself as a strawman argument. MTBF/MTBO is something that is measurable, and trackable, and when statistically significant data is available, can be used objectively.
Id generally agree that back-specifying oils to older engine designs may be concerning, and done for limited reasons. That said, even that may be based upon oil improvements to provide sufficient basis to comfortably allow their specification and use.
But here we have a modern, recent engine design. One that may have had to meet rolling constraints of the modular design, but seems to be a clean sheet approach. And nobody can buy that some of the benefits of thinner oils may have been leveraged in this design from the start?!? I find that dubious.
My point about the selection of viscosity for my 135i mirrors your mention of Toyota using 0w-16 and saying to go higher. And the loss of viscosity-temperature charts in manuals is idiotic.
But not for one second does that mean that a new engine design would be running 50wt by the manual if CAFE didn't exist. And even then it would be under certain considerations, and likely cause other compromises in other use scenarios.
For the marginal fuel economy benefit if any that a 20wt oil provides, in a new tech engine, to think that engineers are just blind to potential advantages to be leveraged by design is just ridiculous in and of itself.
Again, if automakers were so scared of cafe, they would not be pushing more and larger, and higher output engines everywhere. They would be putting smaller, higher loaded, etc optimized engines.
Yet I'm driving a rental suburban right now. 355hp. That's 65hp more than the vortec 454 made in 1998. If CAFE only ruled the roost, we wouldn't be here. High power engines would only be available at gvwr that are exempt, vendors would notifier such power for vehicles that affect governmental surcharges.
The technologies that get us 454 big block power in a 5.3L v8; the tech that allows a current 4cyl to outperform a prior model v6, all this goes in exact opposition of CAFE, and yet much of the tech is very much the same. The tech would have come regardless, and that includes thinner oils. Id agree that putting a 1.0L 3cyl turbo in a midsize sedan IS CAFE. But not specifying the marginal improvement if any, of a 20wt oil, into an otherwise inefficient and high power platform isn't necessarily so in and of itself, as applied to a modern, clean sheet design engine.
As you should know, engineering is all about turning multiple knobs and finding the best value proposition. Since longevity isn't practically compromised, taking advantage of the oil viscosity and performance knob was going to happen regardless. That's my point.
Can you cite the Honda chart so that we can read the paper and evaluate relevance of claims? There just isn't that much Autobahn to drive in routine use, and for most of the world....
