Toyota's reasoning for 0w20 viscosity engine oil

[Gokhan]

Originally Posted By: JOD
PDF LINK

Nice link, thanks. I will try to fully read it when I get a chance. It says the same thing about the friction losses I've been saying. They come from mainly bearings and pistons. There are valvetrain losses too of course but since valvetrain runs in boundary lubrication (metal-to-metal with antiwear-additive-film protection), oil viscosity has no effect on that.

I don't think you understood my point. My point is that if your oil-sump temperature is, say 30 C below freezing, your oil-film temperature in the pistons and bearings won't be the same. It will be much higher, probably higher than 100 C. This is because of the large amount of friction generated by sliding parts abruptly heating the thin oil film between them. Therefore, effect of low-temperature kinematic viscosity on engine friction will be much less than you think. It will effect the cold-cranking and cold-oil flow, pressure, and pumbability a lot though.

 

[CATERHAM]

Originally Posted By: Gokhan

My point is that if your oil-sump temperature is, say 30 C below freezing, your oil-film temperature in the pistons and bearings won't be the same. It will be much higher, probably higher than 100 C. This is because of the large amount of friction generated by sliding parts abruptly heating the thin oil film between them. Therefore, effect of low-temperature kinematic viscosity on engine friction will be much less than you think. It will effect the cold-cranking and cold-oil flow, pressure, and pumbability a lot though.

Off topic and therefore having nothing to do with this thread.
But since you brought it up, your hypothesizing clearly shows a lack of first hand experience.
If you had an oil pressure and oil temp' gauge in your car you'd know bearing oil temperature and sump temp's are nowhere as far apart as you claim.
Even starting a cold engine at room temperature, it takes a few minutes before an OP guage will record any drop in bearing oil viscosity. At any given time there no more a few degrees difference in the temperature of the oil pumping through the main bearings and journals and the bulk sump oil temp's in a
4-6 quart engine.

 

[JOD]

Originally Posted By: Gokhan
My point is that if your oil-sump temperature is, say 30 C below freezing, your oil-film temperature in the pistons and bearings won't be the same.


Agreed

Originally Posted By: Gokhan
It will be much higher, probably higher than 100 C.


Disagree...it'll be higher, but not THAT much higher.

Originally Posted By: Gokhan
Therefore, effect of low-temperature kinematic viscosity on engine friction will be much less than you think. It will effect the cold-cranking and cold-oil flow, pressure, and pumbability a lot though.


The problem with your above assertion is that the actual tests which measure frictional losses at the bearing and piston with cold oil (Seq VI-A, stages 5 and 6) is in direct conflict with it. Look at Fig 8 of that paper when you have a chance.

Also, your assertion that systems working in the boundary lubrication regime aren't affected by temperature is also incorrect; if anything, valvetrain losses are actually MORE sensitive to KV (and temperature) than bearings and pistons.

I don't want to overstate this--hths is still the main driver of FE, but there are other factors at play. And those factors grow exponentially in importance until the oil reaches full operating temperatures.

 

[Gokhan]

Originally Posted By: JOD
I don't want to overstate this--hths is still the main driver of FE, but there are other factors at play. And those factors grow exponentially in importance until the oil reaches full operating temperatures.

I guess we somewhat agree but will disagree on how much each effect contributes. We both agree that HTHS is the main contributor and KV is also a contributor but we won't agree on how much it contributes and how much difference 0W- vs. 5W- will make in most weather conditions.

By the way, as we all know the main reason why an engine is inefficient when it's cold is because a cold engine doesn't burn the fuel well and the air - fuel ratio must be kept too rich for combustion in a cold engine. This is a much larger effect than the oil viscosity for why the cold engines are inefficient. Again, not that we didn't know but just to remind it.

 

[Gokhan]

Alright, just did an oil change and using Pennzoil yellow bottle SN/GF-5 5W-20 now! All Pennzoil and SOPUS oil products are sale on O'Reilly now and there is a $7 mail-in rebate.

I wonder how much Toyota 0W-20 costs and even a better question: is it actually better than Pennzoil yellow bottle? Perhaps I will try it in the future. I know PYB 5W-30 is loaded with moly (probably the ultra-strength Infineum trinuclear type)and boron and am hoping that PYB 5W-20 is so as well.

 

[CATERHAM]

Well of course the Toyota 0W-20 is "better" than PYB 5W-20.
Up here the Toyota oil is $5/L which is only about 50 cents more than PYB unless it's on sale.
The SM Toyota oil has almost 3X the moly of PYB.

But unless you have an very accurate butt dino I'd suggest installing an OP gauge. If you do, you won't believe how much lower the OP is on start-up; when I first ran it the 25 psi drop in cold OP on idle was startling.

 

[Gokhan]

Originally Posted By: CATERHAM
But unless you have an very accurate butt dino I'd suggest installing an OP gauge. If you do, you won't believe how much lower the OP is on start-up; when I first ran it the 25 psi drop in cold OP on idle was startling.

Are you talking about the Toyota 0W-20 cold-idle OP? How much was it? What was the ambient temperature? What is the cold-idle OP you normally get with your other oil and what is the other oil? Have you stopped using the Toyota 0W-20?

 

[Gokhan]

Originally Posted By: CATERHAM
The SM Toyota oil has almost 3X the moly of PYB.

Well, the SN Toyota 0W-20 doesn't have that much moly and they've got rid of boron. SN PYB (VOA for 5W-30 available) has a lot of moly and also boron.

Also, Pennzoil is more likely to have the Infineum trinculear moly, since Infineum is co-owned by Exxon-Mobil and Shell. Some types of organic moly have been shown to be very ineffective. In particular, organic moly that doesn't have sulfur has been shown to be completely useless. I don't know what type of moly SM Toyota 0W-20 had and what type the SN Toyota 0W-20 has.

There are very few 0W-20 oils available in the US autostores. There is Mobil 1 0W-20, which is an iffy product and there is Valvoline Synpower, not a well-established synthetic oil. The rest are store brands or Toyota and Honda oils. If you don't like them, you need to use 5W-20, for which there are a lot of choices available.

 

[JOD]

Originally Posted By: Gokhan

I guess we somewhat agree but will disagree on how much each effect contributes. We both agree that HTHS is the main contributor and KV is also a contributor but we won't agree on how much it contributes and how much difference 0W- vs. 5W- will make in most weather conditions.



When you have a chance, you should really give that paper a thorough read. It answers this question in pretty good detail. The answer is "it depends". Long, highway driving with a pushrod engine? hths is overwhelms the equation. Small-displacement 4 valve per cylinder with a timing chain, lots of short trips? Well, things change. Based on some of the various models and engine tests, hths can drop to less than half of the equation with respect to FE. And again, I think it's key to remember than most trips people make are short, so start-up/warm-up viscosity is a key component of real-world FE. So, engine design and driving habits play a significant role in determining the importance of hths in FE.

My other favorite nugget in that paper is the debunking of the notion that film strength decreases as viscosity decreases. It's interesting that in a key area such as the piston rings, 5W20 provides significantly thicker films. So much for thin oils ruining everyone's engine....

BTW, if you're looking to try a very high VI, high moly 0W20 oil, you should check out this thread. Turns out, they found a bunch more. You aren't too far, so shipping should be cheap.

 

[Gokhan]

Originally Posted By: JOD
Originally Posted By: Gokhan

I guess we somewhat agree but will disagree on how much each effect contributes. We both agree that HTHS is the main contributor and KV is also a contributor but we won't agree on how much it contributes and how much difference 0W- vs. 5W- will make in most weather conditions.



When you have a chance, you should really give that paper a thorough read. It answers this question in pretty good detail. The answer is "it depends". Long, highway driving with a pushrod engine? hths is overwhelms the equation. Small-displacement 4 valve per cylinder with a timing chain, lots of short trips? Well, things change. Based on some of the various models and engine tests, hths can drop to less than half of the equation with respect to FE. And again, I think it's key to remember than most trips people make are short, so start-up/warm-up viscosity is a key component of real-world FE. So, engine design and driving habits play a significant role in determining the importance of hths in FE.

My other favorite nugget in that paper is the debunking of the notion that film strength decreases as viscosity decreases. It's interesting that in a key area such as the piston rings, 5W20 provides significantly thicker films. So much for thin oils ruining everyone's engine....

BTW, if you're looking to try a very high VI, high moly 0W20 oil, you should check out this thread. Turns out, they found a bunch more. You aren't too far, so shipping should be cheap.

The paper seems really good. I will read it when I have time. The conclusion about oil-film thickness vs. viscosity is interesting. I have to read it and think about it to see why it would make sense or why it wouldn't.

I'm trying to think that you need a thicker oil film primarily if your engine runs dirty. For example, diesel engines generate a lot of soot, which is composed of very abrasive particles. If these particles are bigger than your oil-film thickness, they will damage the sliding surfaces. For that reason, there is a well-established relation between HTHS and engine wear for diesel engines. For gasoline engines that run clean (this doesn't apply to all gasoline engines, especially pre-80s or pre-70s engines), you don't seem to need a thick oil film to protect the sliding surfaces and an HTHS viscosity of 2.6 cP -- 0W-20 and 5W-20 oils -- seem to be enough for any modern gasoline engine, and you get the performance enhancement on top of that due to substantially reduced friction.

By the way, my engine is running extremely well with PYB 5W-20, which I just started using. Since the oil consumption has completely stopped after I replaced the valve-stem oil seals, I don't need to use 15W-40 anymore.

 

[Gokhan]

Questions:

Where is Toyota 0W-20 made? Japan, US, or some other country? In other words, what country name is actually printed on the back label of the bottle?

If it's made in US, could it be some generic oil, say Warren Oil etc.?

If it's made in Japan, is it made by several different companies? VOAs seem to be all over the place, indicating different sources. There was even one VOA with KV @ 100 C = 11 cSt, which is outrageous.

I don't feel comfortable using an oil of which I don't know the source, especially if the formulation changes every time I buy it.

 

[fpracha]

Originally Posted By: Gokhan
By the way, my engine is running extremely well with PYB 5W-20, which I just started using. Since the oil consumption has completely stopped after I replaced the valve-stem oil seals, I don't need to use 15W-40 anymore.

hi Gokhan,
Yes hths & kv both affect FE together with engine design & driving habits, as all agree here

Are you getting much better FE and what % improvement, after switching from the 15W40 to 5W20 ?
Do you make more highway trips or more short trips overall ?

 

[Gokhan]

Originally Posted By: fpracha
Are you getting much better FE and what % improvement, after switching from the 15W40 to 5W20 ?
Do you make more highway trips or more short trips overall ?

I just changed the oil today. Perhaps I will get an idea on the improvement in the fuel economy next week.

I do mixed driving on city streets, high-speed freeway driving, as well as low-speed (stop-and-go or slow-moving) freeway driving if I'm driving the during the rush hour.

In the past I got about 7% improvement in fuel economy when I switched to 5W-30 from 15W-40. The valve-stem oil seals were bad back then though and I had to switch back to 15W-40. I replaced them about 6,000 miles ago, which stopped the oil consumption.

 

[fpracha]

Originally Posted By: Garak
Originally Posted By: CATERHAM
Additionally their are no "super-high quality 15W-40 oils". It's a dino grade

Well, RP does market a synthetic 15w-40 HDEO. I can't name any others, though.

So Would this RP 15w-40 be better in FE compared to the synthetic brands, specially the dinos ?

What about the LE 8800 (made for long drain service in gas and diesels)... it mentions to contain a special viscosity modifier, and Gokhan you have said earlier that the viscosity modifier is also very important together with the hths of an oil, in contributing to FE ?

Originally Posted By: Gokhan
Where is Toyota 0W-20 made? Japan, US, or some other country? If it's made in Japan, is it made by several different companies? VOAs seem to be all over the place, indicating different sources. There was even one VOA with KV @ 100 C = 11 cSt, which is outrageous.

its probably Japan.
kv of 11cSt @ 100C... This could be true for a 0W30 but for a 0W20 I doubt it!
Why do you say the 11cSt@100C is outrageous though - would it kill the FE or does it imply lower base oil quality ?
Originally Posted By: Gokhan
I just changed the oil today. Perhaps I will get an idea on the improvement in the fuel economy next week.
I do mixed driving on city streets, high-speed freeway driving, as well as low-speed (stop-and-go or slow-moving) freeway driving if I'm driving the during the rush hour.

In the past I got about 7% improvement in fuel economy when I switched to 5W-30 from 15W-40.

So if you were actually mostly driving on city streets, the change from 15W40 to 5W30 should give an even higher FE improvement than the 7% you experienced, right ?

 

[Mr_Joe]

I did an oil change on a 2.4 liter Camry engine yesterday. I went with 0-20w Mobile One for the Winter.

 

[btanchors]

Quote:
(originally posted by Gokhan)There are very few 0W-20 oils available in the US autostores. There is Mobil 1 0W-20, which is an iffy product and there is Valvoline Synpower, not a well-established synthetic oil.


Can you elaborate on your comment about M1 0W-20? Why is it an "iffy" product?

 

[CMMeadAM]

You can always trot on down to your local Toyota Store and check for yourself......but it's made in the US by XOM and says
"made in the USA from domestic and imported components" on the bottle.

 

[demarpaint]

Originally Posted By: btanchors
Quote:
(originally posted by Gokhan)There are very few 0W-20 oils available in the US autostores. There is Mobil 1 0W-20, which is an iffy product and there is Valvoline Synpower, not a well-established synthetic oil.


Can you elaborate on your comment about M1 0W-20? Why is it an "iffy" product?


I'd be interested too, since once my Edge 0W20 SM stash is gone I'm considering going to M1 0W20.

 

[tig1]

Originally Posted By: btanchors
Quote:
(originally posted by Gokhan)There are very few 0W-20 oils available in the US autostores. There is Mobil 1 0W-20, which is an iffy product and there is Valvoline Synpower, not a well-established synthetic oil.


Can you elaborate on your comment about M1 0W-20? Why is it an "iffy" product?


Well he can't. He dropped a dime on M1 0-20 but can't explain.

 

[CMMeadAM]

Awwww Tig.....give him a chance......but be ready for MORE
"iffy" statements..............