0w-40 less viscous at some start temps than 10-30?

[OceanRuns]

I was looking at the chart below (found here in another thread). Seems that at temps above 10 degrees, Mobil 0w-40 is thicker than 10w30? Thus providing less start-up protection at those temperatures?

TEMP * M1 0W-40 * GC 0w30 * M1 10w30 * M1 0W-20
-20 * 2661.5 * 2609.0 * 3424.8 * 1712.7
-10 * 1197.8 * 1127.1 * 1332.9 * 730.8
0 * 599.3 * 546.6 * 595.7 * 352.8
10 * 327.6 * 291.8 * 298.3 * 188.5
20 * 192.9 * 168.8 * 164.1 * 109.5
30 * 121.0 * 104.4 * 97.6 * 68.3
40 * 80.0 * 68.4 * 62.0 * 45.1
50 * 55.4 * 47.0 * 41.6 * 31.3
60 * 39.8 * 33.7 * 29.2 * 22.6
70 * 29.7 * 25.0 * 21.4 * 17.0
80 * 22.7 * 19.1 * 16.1 * 13.1
90 * 17.8 * 15.0 * 12.5 * 10.4
100 * 14.3 * 12.0 * 10.0 * 8.4
110 * 11.7 * 9.8 * 8.1 * 6.9
120 * 9.8 * 8.2 * 6.7 * 5.8
130 * 8.2 * 6.9 * 5.7 * 5.0
140 * 7.0 * 5.9 * 4.9 * 4.3
150 * 6.1 * 5.1 * 4.2 * 3.7

 

[OVERKILL]

Of course. The advantage of the oil being 0w-xx only happens at extremely cold temperatures, and over oils of the same grade. So 0w-40 will tend to be thinner than a 5w-40 at lower temperatures. But will be heavier than a 5w30 or 10w30 until temperatures significantly below 0.

 

[147_Grain]

0W-40 does indeed take more TIME to flow through the oil galleys to vital engine parts than 30 or 20 weight oils.

 

[OceanRuns]

Learned something new. I was under the impression that a 0w would flow better at start-up, period. Oh well. I just put 0w-40 in my T100 yesterday, come today to find out the 5w30 it had flowed better at start-up. LOL.

Hate second guessing myself.

 

[OVERKILL]

Originally Posted By: OceanRuns
Learned something new. I was under the impression that a 0w would flow better at start-up, period. Oh well. I just put 0w-40 in my T100 yesterday, come today to find out the 5w30 it had flowed better at start-up. LOL.

Hate second guessing myself.


Nothing wrong with learning

The 0w denotation only indicates a level of performance in extreme cold. It doesn't change the fact that a 40-weight oil is going to be heavier than a 30 at pretty much all temperatures one is likely to experience. Look at your table you see that even a 10w30 is thinner until things get pretty frosty.

Around the 0 degree mark, the 0w-40 begins to show its superior cold temperature performance with respect to the 10w30. The reason that GC mirrors the 0w-40 so closely is that it is near the top of the 30-weight chart, so the difference in operating viscosity between it and the 0w-40 isn't much.

 

[OVERKILL]

Originally Posted By: 147_Grain
0W-40 does indeed take more TIME to flow through the oil galleys to vital engine parts than 30 or 20 weight oils.


Completely temperature dependant. And with a positive displacement oil pump and a filter with a decent ADBV, that amount of time in temperatures where the 0w-40 doesn't have the advantage is really insignificant.

 

[randomhero439]

Dont forget, it goes both ways. If you overheat the oil, generally a 0w oil will not thin out as much as a 5w or 10w oil.

 

[OVERKILL]

Originally Posted By: randomhero439
Dont forget, it goes both ways. If you overheat the oil, generally a 0w oil will not thin out as much as a 5w or 10w oil.


That's not accurate. The HTHS of the oil is the indicator as to how viscous an oil is at higher temperatures (it is measured at 150C).

 

[147_Grain]

OVERKILL is Correct!

It's the 2nd number that (mostly) makes the difference in HTHS. 1st number (mostly) relates to cold temperature properties; that is why the W in 0W-40 stands for Winter.

 

[randomhero439]

Good thing im not talking about HTHS then! I was speaking of viscosity index. Since 0w oil generally have a higher VI, they will thin out less when overheated.

 

[OVERKILL]

Originally Posted By: randomhero439
Good thing im not talking about HTHS then! I was speaking of viscosity index. Since 0w oil generally have a higher VI, they will thin out less when overheated.


VI can be, and often is manipulated by polymer. An oil with less polymer is going to be less likely to sheer, so again, you argument isn't factual.

Do you have any examples of what you claim in application? Think about this: the reason Honda spec'd 10w30 for the S2000 instead of 5w30 was that the 10w30 was less sheer prone. But it has a lower VI.

HTHS is the true indicator of an oil's high temperature viscosity. And this is why that value, NOT VI, is what is used to define certain classes of lubrication performance as well as spec'd by various manufacturer approval/certification requirements, usually with respect to European cars.

 

[147_Grain]

Furthermore:

Some manufactures will use a lot of VI in order to make-up for a weaker (less expensive basestock).

Oils with high quality basestocks typically have excellent HTHS and use less VI. A lower VI is better for HTHS because this means the oil is performing well due to MORE basestock and less additives.

 

[gregoron]

Nice thread. It's a refresh on HTHS and VI.

OVERKILL, wouldn't an oil with a higher VI be more desirable than one with lower for the same grade oil (i.e. M1 0W-40 vs Edge 0W-40)? I'm still not clear about VI values.

How would sheer come into play on oils with different spread like 10W-40 which has low VI vs 5W-40 that tend to have higher VI if their HTHS is the same?

 

[OVERKILL]

Originally Posted By: 147_Grain
Furthermore:

Some manufactures will use a lot of VI in order to make-up for a weaker (less expensive basestock).

Oils with high quality basestocks typically have excellent HTHS and use less VI. A lower VI is better for HTHS because this means the oil is performing well due to MORE basestock and less additives.


You are combining VI and VII

An oil that is reliant on a lot of VII to achieve its final visc spread is more prone to shear than one that uses base oils with naturally high VI's in the first place.

I think an example of that would be the comparison in the latest PQIA line-up where if you look at the volatility of the Lucas "synthetic" and compare it to PU, M1...etc that it gets dominated. They likely used cheap base oils and relied on a pile of VII's to achieve the final viscosity spread.

Another example would be the latest Japanese ultra-high VI synthetics from Mazda, Toyota...etc. They have awful NOACK volatility because that VI is heavily propped-up with polymer. But they aren't designed for demanding applications that are going to heat and shear the oil either. So there is some relativity there.

Ultimately, VI is just a characteristic of a finished lubricant. How the manufacturer achieved that VI is more significant than the VI itself. An oil using expensive naturally high VI base oils compared to an oil that used less expensive base oils and piles of polymer, if the latter oil has the higher final VI, is it a better lubricant? I don't think so. It will be more likely to break down and experience permanent shear than the oil that relies on basestock quality.

 

[OVERKILL]

Originally Posted By: gregoron

OVERKILL, wouldn't an oil with a higher VI be more desirable than one with lower for the same grade oil (i.e. M1 0W-40 vs Edge 0W-40)? I'm still not clear about VI values.


Usually when comparing oils that have a similar list of certs and approvals like the ones you've mentioned, it is safe to choose the oil with the higher VI, as you are guaranteed a specific level of performance and a certain quality of basestock and additive package are required to obtain the approvals the oil has.

However, normally in the cases like these ones, the difference in VI is so small that you are really splitting hairs.


Quote:
How would sheer come into play on oils with different spread like 10W-40 which has low VI vs 5W-40 that tend to have higher VI if their HTHS is the same?


It is going to depend on the quality of the components used to arrive at that VI. However, you can look at additional characteristics like NOACK, which will then tell you more about the quality of the base oils used. The PU 5w-40 (SN version) doesn't have the world's greatest VI by any stretch of the imagination, but its NOACK volatility is outstanding! This shows that it uses high quality (in this case, GTL) base stocks.

 

[147_Grain]

Quote:
OVERKILL: An oil that is reliant on a lot of VII to achieve its final visc spread is more prone to shear than one that uses base oils with naturally high VI's in the first place.


That's what I meant to say; I'm not as articulate or well versed as you.

Thanks OVERKILL.

 

[randomhero439]

Originally Posted By: OVERKILL
Originally Posted By: randomhero439
Good thing im not talking about HTHS then! I was speaking of viscosity index. Since 0w oil generally have a higher VI, they will thin out less when overheated.


VI can be, and often is manipulated by polymer. An oil with less polymer is going to be less likely to sheer, so again, you argument isn't factual.

Do you have any examples of what you claim in application? Think about this: the reason Honda spec'd 10w30 for the S2000 instead of 5w30 was that the 10w30 was less sheer prone. But it has a lower VI.

HTHS is the true indicator of an oil's high temperature viscosity. And this is why that value, NOT VI, is what is used to define certain classes of lubrication performance as well as spec'd by various manufacturer approval/certification requirements, usually with respect to European cars.


Yes in 1999 Honda specced the s2k for conventional 10w30 to reduce sheering because here are less VII. However, if a 5w30 conventional could produce the same sheer resistance, wouldnt Honda use a 5w30? So why is Porsche, Aston, GT-R, (corvette?) and various other high performance cars specced for M1 0w-40 with its high VI and likely high VII count.

On a side note:
I would also like to share, that i believe there is a positive correlation between the viscosity index/volatility ratio and the quality of the base stock. Thoughts on that?

 

[OVERKILL]

Originally Posted By: randomhero439


Yes in 1999 Honda specced the s2k for conventional 10w30 to reduce sheering because here are less VII. However, if a 5w30 conventional could produce the same sheer resistance, wouldnt Honda use a 5w30?


Yes, that's exactly my point. But they didn't, because it wasn't. So what are you getting at?

Quote:
So why is Porsche, Aston, GT-R, (corvette?) and various other high performance cars specced for M1 0w-40 with its high VI and likely high VII count.


Who says M1 0w-40 has a lot of VII's in it? Because it has a wide visc spread? It is also a relatively heavy lubricant compared to your typical 30-weight oils with an HTHS of 3.8cP on the most recent formula. We also know it leverages high quality base stocks because it has a low NOACK. VISOM, which this oil uses, I believe is available in some relatively high VI versions, from what I recall Molakule saying, so it would make sense that with the correct (not cheap) blend of base oils, minimum polymer can be used to achieve the required visc spread. Also, its VI is 185, certainly greater than some other more pedestrian (read: less expensive) lubricants, but certainly not stratospheric like some of the Japanese ultra-lights.

To compare two very similar (performance and certification-wise) oils:

M1 0w-40:
40C: 75cP
100C: 13.5cP
HTHS: 3.8
Flash: 230C
NOACK: ~9% (was 8.8% for the SM version)
VI: 185

PU Euro 5w-40
40C: 80.7cP
100C: 13.2cP
HTHS: 3.88
Flash: 216C
NOACK: 6.8%
VI: 166

There's only a 5cP difference in visc between the two at 40C. But this results in the difference of the VI that we see between the two lubricants. However the NOACK also seems to reflect that, indicating that despite not using a lot of VII, M1 0w-40 has more of it than PU Euro 5w-40.


Quote:
On a side note:
I would also like to share, that i believe there is a positive correlation between the viscosity index/volatility ratio and the quality of the base stock. Thoughts on that?


Generally, the heavier the base oil, the lower the NOACK. However, as Molakule pointed out in another thread, you can blend various base oils together to achieve a reasonable VI with minimal amounts of polymer. GTL appears to have exceptional volatility resistance, as indicated in the NOACK of all the more recent Pennzoil Ultra oils. Because of the use of this new base oil, the VI's have all gone down on these products. This isn't a coincidence, it is a relationship. The Group III+ base oils they were using before, likely supplemented with a decent dose of polymer to achieve the spread has been replaced by a superior base oil with a higher natural VI, meaning less (or no) polymer is needed, so NOACK is lower, but so is VI. Compare the PDS's for Platinum to Ultra to see what I mean. For 5w30 Platinum is 177/12.8%, Ultra is 165/6.4%.

If you look at Redline's oils, you will see this relationship as well. Their 5w-20 with its VI of 145 has a NOACK of 8%. Jump to their 0w-20, where you get a higher VI of 166, but the NOACK also goes up to 9%.

Their 5w30 has a VI of 162, NOACK of 6%. But their 0w-30, with a VI of 183 has a NOACK of 9%. A 3% jump.

And there's no arguing that Redline isn't using high quality base oils, right?

Same goes for their 0w-40 and 5w-40 with VI's of 197/170 and NOACK's of 9%/6% respectively (and HTHS values of 4.0 and 4.6).

 

[147_Grain]

OVERKILL:

So in essence, are you saying that Pennzoil Ultra likely uses a higher quality basestock and less VI than Platinum?

Example of VI and NOACK: "Compare the PDS's for Platinum to Ultra ... For 5w30 Platinum is 177/12.8%, Ultra is 165/6.4%" (OVERKILL).

 

[147_Grain]

Pennzoil Ultra Specs:

http://www.epc.shell.com/Docs/GPCDOC_X_cbe_24855_key_140007304052_201207271342.pdf


Pennzoil Platinum Specs:

http://www.epc.shell.com/Docs/GPCDOC_X_cbe_24855_key_140007054941_201202271154.pdf