THE DRIVE TOWARD THINNING ENGINE OILS

Messages
33,803
Location
Southern NJ

"Thinner engine oils cause less friction between the components of an engine and result in a lower amount of energy loss from the movement in the engine, but engage reduced oil film thicknesses, which may generate more wear and limit durability."

"The most viable option for further improving the fuel economy beyond SAE 0W-8 is to increase the viscosity index, because the kinematic viscosities at 40°C and 100°C can be further lowered, which is useful for transient driving profiles, while keeping the HTHS for durability. This approach favors synthetic hydrocarbons, esters and polyglycols."
 

MolaKule

Staff member
Messages
21,438
Location
Iowegia - USA

... This approach favors synthetic hydrocarbons, esters and polyglycols."
It sure does.
 
Last edited:
Messages
348
Location
CA
My take on that interesting blog is thinner oils offer better fuel economy at the cost of shorter engine life. With advanced designs in the motors spinning and moving parts, I question if those engine designs can keep up with the oils as they get thinner.

I was always nervous using super thin oils in my powersport vehicles. The clatter of the motor when using 10W40 vs 20W50, 20W60, 30W or 50W is big.

I've recently switched from 10W-40 to the recommended 5W-30 in my truck and while my engines efficiency went up a bit so did the lifter noise. This is a big change for me. My last truck mostly lived on 20W-40 or 20W-50 and lasted over 300,000 miles.

Thick oil getting harder to find. Fortunately local motorcycle shops and online retailers have it available.
 

MolaKule

Staff member
Messages
21,438
Location
Iowegia - USA
My take on that interesting blog is thinner oils offer better fuel economy at the cost of shorter engine life. With advanced designs in the motors spinning and moving parts, I question if those engine designs can keep up with the oils as they get thinner...
Some have suggested that but as the article says; "Thinner oils anticipated in engines going forward have resulted in the application of thin film coatings and enhanced bearing and ring materials."

However, it's going to take a lot research in both lubricants, parts coatings, and metallurgical materials to convince people that a 0W8 is the way to go.
 

4WD

Messages
13,783
Location
Texas
Folks often make reference to bearing clearance always being tight. Fine and good … but modern computer models, CNC triaxial interpolation … focus on stiffness, and better materials all matter. (All concentric and square for EHL joy).
Then comes coolers, variable displacement oil pumps, piston jets … all in the ECM logic …
 
Messages
348
Location
CA
Some have suggested that but as the article says; "Thinner oils anticipated in engines going forward have resulted in the application of thin film coatings and enhanced bearing and ring materials."

However, it's going to take a lot research in both lubricants, parts coatings, and metallurgical materials to convince people that a 0W8 is the way to go.
Man that is some thin oil. Sounds like oil technology is surpassing engine design at a steady rate.
 
Messages
118
Location
DFW Metroplex
My take on that interesting blog is thinner oils offer better fuel economy at the cost of shorter engine life.
How much shorter?

If 50K less miles, I’m out!

If 50 less miles, I’m in!

Actually, go ahead and just count me in. I’m way too impulsive and reckless to worry about one of my engines failing because of a thin oil issue.

Those engines I have that I don’t get impounded with the car they’re in when I’m arrested will surely be salvaged for resale when the car is driven beyond 200K and sold for $1000 to a casual friend for spare parts for their project build.
 
Messages
1,391
Location
USA
Physics is physics. All things eventually succumb to the concept of "every action has an equal and opposite reaction"- thin oil is no different.

There will come a point of diminishing returns where the physical properties of the materials available ( without adding lines to the periodic table) will not support all the loading required by the desired mass and MOFT.

Where that point is, I don't really know but its there and it is the proverbial "hard stop".
 
Messages
1,391
Location
USA
they must believe they are close to that hard stop already for those engines using a 20...
I tend to believe this is close to correct.

1). In truth all lube regime requirements ( from the machine design perspective) start from a set of requirements ( displacement, HP, torque etc.)- that's the baseline all things are measured against and held to.

2). and then end up with a very long complex differential equation to get there mechanically.

3). Then comes the lube requirements that go to the various OEM s to see what they have ( or can make)

You will stay circling between 2-3 until decisions and revisions are done

Now if there is some unlikely or physically impossible situation- you may have to go and revise #1

Now you have an engine "designed around" a lubricant ( in terms of properties that the engine must have to function)

That sounds good but as things get leaner/meaner, cost constraining and so forth- your "margin of deviation" equally gets smaller because each input of that equation has a range and the closer it gets to that, hard machining requirements change.

When they get to the end of that rope, tie a knot and hang on.
 
Messages
3,417
Location
Millbrae, CA
some SAE paper noted that lubes are really pretty good at reducing friction and there was not much more lowering of visocity would do.

Now is more to do with better manufacturing of parts and design will give next round of improvments.
 
Top