CAFE Standards in the US and Oil Grades

The United States is a far harsher climate than Europe so it is kind of silly to compare their choice of oil. Temperatures here range from 115F to -45F. It is a huge country. Many parts are extremely arid and dusty, while others are wet. Cherry picking an owners manual to claim that some other country's oil recommendation is right and your own country's is wrong, is unconvincing.
You realize that the climate in the northwest United States is very similar to that of England, correct?

Also, yes the southeast and southwest in the US have 'harsher' climates than most of Europe, but our oil specs don't vary by region. So I think that this has more to do with regulation than it does with climate.
 
As my mother would say, "What does that have to do with the price of cheese?"

I am legitimately curious why viscosities are spec'ed differently in different parts of the world. Carbon dioxide is not the only by-product of combustion and in the US, efficiency is further driven down by the 10% ethanol we use in our fuel since it is less energy-dense than gasoline hydrocarbons.

So you know enough about "CAFE" but haven't seen one of the probably dozens of other threads around here on the subject?
 
And it's a misconception that engine clearances are "designed for thinner oil" because when you look at bearing clearances for instance between an engine made in 2020 vs one made in 1980 they have the same design clearances for all practical purposes. That's why you can run anything from 0W-20 to 20W-50 in the same engine and it's not going to "blow-up".

5W-30 IS CAFE!! In the 1980's, there were blurbs in many (mainly GM) manuals that said "5W-30 is not recommended for sustained highway operation" yet today it's a "thick" oil. And whether your bearing clearances statement is true or not, many engines starting in the 1990's relied more on OHC and DOHC for efficiency and to balance the incremental increases in horsepower with the demands for greater fuel economy, and I am pretty sure OEM's wanted oils that "flowed faster to the top of the motor", or so we were told in quickie lube training, irregardless of whatever the standard statement of "there is a coating of oil left in the upper parts of a motor anyways" or not...

Totally agree ... if there could only be one oil sold in the world it would most likely be 5W-30 or 0W-30.

I agree more or less. But slightly thicker oils in Europe also comes into play in regards to extended OCIs, no one wants a 20W when the 30W may well sheer down after 10K and the 20W may get close to a 15W in an extended interval, all hypothetical of course...
 
Last edited:
From about 1987 to about 2004, Total Fleet and Import Care declined in MPG's ! Light Truck a bit flat, but Domestic Car went up since CAFE started recording. Wholly wombat. Imports were always better, less the few spots on the chart. Hmmmm.
214a302996b6d2fcfab1fe5a360f11cf67775294.png
 
Yes, there are 200 million vehicles registered in the USA and the ones consuming gasoline burn about 10 million bbls per day or 420 million gallons per day. The 1.5% is over 6 million gallons per day.

It is also a legitimate national security issue when a large portion of the US budget goes to insuring the military can project forces to the Middle East and secure no small part of our oil lifeline. In a sense we rob Peter to pay Major Tom..
 
From about 1987 to about 2004, Total Fleet and Import Care declined in MPG's ! Light Truck a bit flat, but Domestic Car went up since CAFE started recording. Wholly wombat. Imports were always better, less the few spots on the chart. Hmmmm.
214a302996b6d2fcfab1fe5a360f11cf67775294.png

A lot of that has to do with safety and vehicles getting larger and heavier with the advent of airbags-all-around overall. Look at a 2018 Honda Civic and compare it to a 1988 Honda Accord, the "compact" Civic is the same size as a midsized passenger sedan from the late 80's if not bigger..
 
5W-30 IS CAFE!! In the 1980's, there were blurbs in many (mainly GM) manuals that said "5W-30 is not recommended for sustained highway operation" yet today it's a "thick" oil. And whether your bearing clearances statement is true or not, many engines starting in the 1990's relied more on OHC and DOHC for efficiency and to balance the incremental increases in horsepower with the demands for greater fuel economy, and I am pretty sure OEM's wanted oils that "flowed faster to the top of the motor", or so we were told in quickie lube training, irregardless of whatever the standard statement of "there is a coating of oil left in the upper parts of a motor anyways" or not...

Any time there is a push to use thinner oil it's a "CAFE oil" because CAFE is the one pushing for it. The GM statement was a result of engineers knowing that thicker oil creates a larger MOFT and therefore adds engine protection. Apparently back in those days they felt that 5W-30 was a "down grade" in providing engine protection compared to the thicker oils of that era.

As far as oils that "flowed faster to the top end", that whole scenario is only applicable to cold engine start-ups in very cold weather and is dependent on the xW rating of the oil. With a PD oil pump, the oil (if perfectly "pumpable") is delivered to the top end just as fast regardless of viscosity, but once the oil leaves the supply gallery and is free to flow over parts in the top end is when this would matter the most. Obviously you want an oil that flows well in very cold weather to ensure proper top end lubrication. Oil supplied to pressure fed/supplied components like journal bearings it's not as critical
 
Cherry picking an owners manual to claim that some other country's oil recommendation is right and your own country's is wrong, is unconvincing.

In these ''other'' countries the manual gives an oil temp chart...the various grades recommended for various temps - our choice of oil. In New Zealand a 20W-50, or a 0W-20, and everything between is good for year round use.
 
Fallacy and conjecture. When has a oil proven to add any meaningful power?

As for protection, it’s there.

Ask the Pro Stock guys why they run 0W-3 if it adds no meaningful power. I would say it's been pretty well proven it's faster than the 20W-50 they ran years ago.
 
Ask the Pro Stock guys why they run 0W-3 if it adds no meaningful power. I would say it's been pretty well proven it's faster than the 20W-50 they ran years ago.


Is this increased power measured in fractions of seconds? I know that every tenth of a second is a big deal to them. For us regular drivers we will not know the difference
 
Aren't race teams using the lightest oil possible? Must be a reason.
Depends on the venue I think. I know a few years back it was shown that M1 0w-40 was the oil of choice for numerous teams at LeMans so for longer duration events, a heavier oil may be necessary. I believe Nascar qualifies on something insanely thin and then bumps it up to a heavier lube for the main event as another example.
 
Depends on the venue I think. I know a few years back it was shown that M1 0w-40 was the oil of choice for numerous teams at LeMans so for longer duration events, a heavier oil may be necessary. I believe Nascar qualifies on something insanely thin and then bumps it up to a heavier lube for the main event as another example.
I'd be curious to know what those grades are for Nascar.
 
Back
Top