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

[randomhero439]

Originally Posted By: 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).


Basically he is saying: Due to the higher quality base stock Ultra, the oil can achieve the same VI as a lower quality basestock+VII, without sacrificing NOACK. Which is why ive been "researching" recently.

With Pennzoil Ultra 10w30 and Redline 10w30, (149/4.8) > (142/6) respectively. So does this mean that Ultra has a more sheer stable base stock?

So Overkill, your saying Mobil 1 0w-40 likely uses little VII? Which would explain its slightly below average NOACK and still high VI, correct? Which would make the oil very sheer stable and why its a good pick for any euro car.

Now this brings into question about the quality of polymers and how resistance to sheer they are. Seems like a whole new ball game... any light you can shed on this?

 

[supercity]

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.


What about this

Joe Gibbs @ 1:30

 

[OVERKILL]

Originally Posted By: randomhero439
Originally Posted By: 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).


Basically he is saying: Due to the higher quality base stock Ultra, the oil can achieve the same VI as a lower quality basestock+VII, without sacrificing NOACK. Which is why ive been "researching" recently.

With Pennzoil Ultra 10w30 and Redline 10w30, (149/4.8) > (142/6) respectively. So does this mean that Ultra has a more sheer stable base stock?

So Overkill, your saying Mobil 1 0w-40 likely uses little VII? Which would explain its slightly below average NOACK and still high VI, correct? Which would make the oil very sheer stable and why its a good pick for any euro car.

Now this brings into question about the quality of polymers and how resistance to sheer they are. Seems like a whole new ball game... any light you can shed on this?



Pretty much bang-on. And while newer polymers are more sheer resistant, I believe they still negatively affect the volatility of the lubricant, which is why NOACK is such an important figure

M1 0w-40 is, as noted, an exceptional lubricant. But I am REALLY impressed by these new ultra-low NOACK SOPUS products. And I have NEVER used SOPUS oils in ANY of my vehicles, EVER. I like to think it takes a lot to impress me and SOPUS has. That's why I bought two cases of Ultra Euro

 

[mechtech2]

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.


You are correct in some circumstances. If we compare oils of the same HOT viscosity, things are more what you expect - the 0 should have an edge..
But a thin hot to a thick hot one is/t really a fair comparison.