HD engine, economy and wear 5W30 vs 0W20

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"the potential for friction reduction using ultra-low viscosity lubricants is explored by investigating the friction power losses using 0W20 lubricants. It is found that a friction reduction of about 8% can be achieved for the journal bearings using a 0W20 lubricant with a 3.6 mPa s HTHS-viscosity.
A more common 0W20 oil with a HTHS-viscosity of 2.8 mPa s achieves the same friction reduction, but shows the presence of metal-metal contact for full load operation. This metal-metal contact might be able to be addressed by suitable additive technology of the lubricant or alternative surface technology for the shaft or bearing."

- in other words, use a thicker oil for high stress situations to avoid wear & failure. But we already knew that.
 
Originally Posted By: bigt61

- in other words, use a thicker oil for high stress situations to avoid wear & failure. But we already knew that.


I would translate it as "use a higher HTHS oil..."

The 3.6 HTHS 0w20 appeared to perform comparably to the 3.6 HTHS 5w30, but the 2.8 HTHS 0w20 showed excessive metal to metal contact before they reached full loading.

Of course there probably is a load point where even at 3.6 HTHS, a 20-weight won't protect as well as a 30, but it may never be reached in a particular engine design.
 
Interesting paper.

We are currently investigating PAO-ester polymer chemistries and IL chemistries as oil additives to sustain HTHS values for 0W20's in Diesels, from a grant provided by two large agricultural and off-road equipment manufacturers.

Our ME group is working on laser formed "micro-grooved" bearing materials to provide controlled leakage in order to provide enhanced bearing cooling.

Just saying, there are many approaches to maintaining HTHS and bearing cooling.
 
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Yeah, interesting article. 8% reduction in friction at idle with either 0w20 compared to 30 weight, but NO reduction of friction at higher power output.

Seems to me if you have a city only car with lots of idle time the 0w20 would be a benefit.

This also seems to back up the concerns that 20 weights may allow accelerated wear compared to 30 weights.
 
Originally Posted By: Kuato
Yeah, interesting article. 8% reduction in friction at idle with either 0w20 compared to 30 weight, but NO reduction of friction at higher power output.

Seems to me if you have a city only car with lots of idle time the 0w20 would be a benefit.

This also seems to back up the concerns that 20 weights may allow accelerated wear compared to 30 weights.


But they don't have to with proper formulation.
 
Originally Posted By: MolaKule
Originally Posted By: Kuato
Yeah, interesting article. 8% reduction in friction at idle with either 0w20 compared to 30 weight, but NO reduction of friction at higher power output.

Seems to me if you have a city only car with lots of idle time the 0w20 would be a benefit.

This also seems to back up the concerns that 20 weights may allow accelerated wear compared to 30 weights.


But they don't have to with proper formulation.


True, the article did suggest that additives could eliminate the metal to metal contact.
 
Originally Posted By: MolaKule
Originally Posted By: Kuato

But they don't have to with proper formulation.


True, the article did suggest that additives could eliminate the metal to metal contact.


More than that- the article noted metal-to-metal contact ONLY ywith the low-HTHS 0w20, not with the high HTHS 0w20.
 
Those are some pretty wonderful oils that they are testing.
But answer me this: what kind of trick of petroleum chemistry are they pulling to get two different HTHS values out of the 0w20 oil which has one set of KV40, KV100, and density values?

And my standard engine designer's complaint of having to redesign the engine to live on the oil they desire to use. I say that's the tail wagging the dog.
 
Originally Posted By: A_Harman
...But answer me this: what kind of trick of petroleum chemistry are they pulling to get two different HTHS values out of the 0w20 oil which has one set of KV40, KV100, and density values?...


They didn't divulge the formulations.
 
Originally Posted By: Kuato
Originally Posted By: MolaKule
Originally Posted By: Kuato
Yeah, interesting article. 8% reduction in friction at idle with either 0w20 compared to 30 weight, but NO reduction of friction at higher power output.

Seems to me if you have a city only car with lots of idle time the 0w20 would be a benefit.

This also seems to back up the concerns that 20 weights may allow accelerated wear compared to 30 weights.


But they don't have to with proper formulation.


True, the article did suggest that additives could eliminate the metal to metal contact.


Not quite, the additives minimise damage at that point...viscosity and design keeps the parts separated, additives keep the wear down when viscosity is pushed to the min.
 
I'm mostly amazed that the KV matters more than the HTHS viscosity to reduce friction in the bearings.

So I'm even more determined to get the lightest kv100 oil with an A3/B4 rating and give that a try for the next OCI
 
Originally Posted By: Jetronic
I'm mostly amazed that the KV matters more than the HTHS viscosity to reduce friction in the bearings.

So I'm even more determined to get the lightest kv100 oil with an A3/B4 rating and give that a try for the next OCI


Depends on the shear rate in the bearing as to whether the oil is operating in the first or second Newtonian period.

I'm using Edge 5W30 A3/B4 in my Tubodiesel, and as I work through the stash, 5W30 A3/B4 is becoming my staple.
 
Originally Posted By: Shannow
Originally Posted By: Jetronic
I'm mostly amazed that the KV matters more than the HTHS viscosity to reduce friction in the bearings.

So I'm even more determined to get the lightest kv100 oil with an A3/B4 rating and give that a try for the next OCI


Depends on the shear rate in the bearing as to whether the oil is operating in the first or second Newtonian period.

I'm using Edge 5W30 A3/B4 in my Tubodiesel, and as I work through the stash, 5W30 A3/B4 is becoming my staple.


Good point.

Thanks for sharing.

The additives are minimizing wear but viscosity still is important.
 
Originally Posted By: buster
Originally Posted By: Shannow
Originally Posted By: Jetronic
I'm mostly amazed that the KV matters more than the HTHS viscosity to reduce friction in the bearings.

So I'm even more determined to get the lightest kv100 oil with an A3/B4 rating and give that a try for the next OCI


Depends on the shear rate in the bearing as to whether the oil is operating in the first or second Newtonian period.

I'm using Edge 5W30 A3/B4 in my Tubodiesel, and as I work through the stash, 5W30 A3/B4 is becoming my staple.


Good point.

Thanks for sharing.

The additives are minimizing wear but viscosity still is important.

If I read correctly, viscosity is the most important thing in minimizing wear.
 
HTHS viscosity seems to be the first line of defense against wear.

Note that the article only mentions bearing wear, and says nothing about ring wear which is more likely to send a carto the scrapyard
 
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Originally Posted By: Jetronic
HTHS viscosity seems to be the first line of defense against wear.


Jetronic, yes, the initial fundimental of lubrication is to keep the parts separated, the ideal "zero wear" condition.

It's not a condition that exists in areas like the cam, lifters, and piston rings at the top and bottom reversal points, where the additives are in play.

As we move to a lower viscosity future, the additives come into play more frequently, and in more areas.

Originally Posted By: Jetronic
Note that the article only mentions bearing wear, and says nothing about ring wear which is more likely to send a car to the scrapyard


Rings are a bit more tricky, being hydrodynamic in the mid stroke (to the point that thermal barrier coatings are being applied to drop the mid stroke viscosity majorly), and heavily additive dependent at the ends of the stroke.
 
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