0W8 and 0W12 API discussion

[gfh77665]

I wanna meet the engineer that poured some 0w20 and declared "TOO THICC" and began work on 16 and 8

Engineers don't decide anything, oil wise. People in Washington D.C. make the decisions what oil you will use.

 

[PandaBear]

It is designed for engines that are designed for it.

Variable flow oil pump means they can increase and reduce flow as the engine need and therefore no longer do we need a much thicker oil for low rpm high stress conditions, and therefore we can now use oil that's thinner so high rpm low load, or cold start, would benefit.

Nobody is telling you to fill your 5w30 engine with 0w8.

 

[gfh77665]

No, instead, they (DC) are eliminating the 5w-30 engines.

 

[Redhawk454]

That was me~!
I have used 5W-20 motor oil in every vehicle I've ever owned starting with a new Dodge Polara 500 in 1965 with a 383 cu in motor. That first oil was Atlantic Imperial. I've lived in NJ and FL. I've never had an oil related engine failure.
My father drove a 1956 Studebaker Power Hawk powered by a 259 cu in V-8 which he drove for 170,000 miles before trading it. He used 20 wt oil year round changing oil and filter every 10,000 miles. At trade in time he was using 1/2 quart of oil every 5,000 miles, and that usage was diagnosed as being from deteriorated valve seals.
Thinner motor oil flows more easily than thick oil, and moves more quickly to every part of you engine at "cold start". I think that this is a critical consideration since the greatest amount of engine wear occurs at start up.

u sure about that

 

[PandaBear]

No, instead, they (DC) are eliminating the 5w-30 engines.

Evolving, not eliminating.

 

[gfh77665]

How many models now spec 5w-30?

 

[kschachn]

How many models now spec 5w-30?

None. Some may still recommend the grade however.

 

[cptbarkey]

It's suitable for street cars. It's has higher amounts of ZDDP , moly and detergents as well. My last oil was Royal Purple XPR 0w20 and there is a UOA here about it.

Are you planning on a UOA for this 0w8? It should be.. revealing.

 

[twX]

I think that this is a critical consideration since the greatest amount of engine wear occurs at start up.

This is a common misconception. The high wear rates don't occur on startup, they occur within several minutes after startup as the engine is running while it's warming up.

The figure below is from a study where an engine's oil and coolant were manually cooled down while it was running. When coolant temperature is under 30-40°C, the wear rate of the piston rings (slope of the blue line) goes up by a factor of ~40. This was very similar to the wear rate that was measured in a separate test that included a cold start, so the actual engine start didn't seem to have any obvious effect on the wear.

It could be a different story for the journal bearings, which also have some startup/warmup wear, but it's not as severe as it is for the pistons and liners. Cams are not very susceptible to either startup or warm-up wear.

 

[deven]

Are you planning on a UOA for this 0w8? It should be.. revealing.

Yes I will definitely do a UOA on this oil.