Who's the current main-stream favourite for 5w40 applications (high temp/shear)

[ZeeOSix]

I'm new to that brand, i'm guessing that means it's not exactly mainstream and at $15/qt ?

High Performance Lubricants (HPL) is a vendor on BITOG. You can order it from them and have it shipped.

High Performance Lubricants PCMO Series

This is the first series of our PCMO groups. https://www.hplubricants.com/wp-content/uploads/2021/08/PC-Engine-Oil-PDS.pdf

bobistheoilguy.com

 

[MaDMaXX]

Am i losing anything going to a 0w40?

I'm seeing SP rated Penzoil 0w40 @ 13 cSt for only $25/jug.

 

[RDY4WAR]

Am i losing anything going to a 0w40?

I'm seeing SP rated Penzoil 0w40 @ 13 cSt for only $25/jug.

A 0W-40 will usually have a lower viscosity initial base oil with more VII polymer resulting in more temporary and permanent shear as well as being more volatile. The HTHS and HTFS will be lower. The only benefit is in the CCS. If you're not cranking the engine in -35°F temperatures, you won't see that benefit.

High Performance Lubricants PCMO 5W-40 has an HTHS of 4.248 and is $9.94/qt with the 15% BITOG discount.

 

[MaDMaXX]

So the HTHS rating has to be 3.5 or higher for the spec, so it's not going to be any lower.

Can you explain what resulting in more temp and permanent shear means?

 

[MaDMaXX]

Euro L 5w30

 

[MaDMaXX]

Euro 0w40

 

[RDY4WAR]

So the HTHS rating has to be 3.5 or higher for the spec, so it's not going to be any lower.

Can you explain what resulting in more temp and permanent shear means?

When formulating a wide spread like a 0W-40, you have to use lower viscosity base oils (4-6 cSt) to achieve the 0W-xx rating. Then a lot of viscosity index improver (8-12%) must be added to bring the viscosity up to a 40 grade at operating temperature.

VII polymers are known to shear, meaning they lose viscosity under pressure. Most VII will have a shear stability index (SSI) of 22-35%. What that means is that much of the viscosity added by the VII can be lost during operation.

Let's say the base oil comes to 6 cSt and then 10% VII is added to bring it up to 13 cSt. Let's say the VII has an SSI of 22%.

13 - 6 = 7
7 x .78 (22% loss) = 5.46
6 + 5.46 = 11.46 cSt

So this theoretical oil would shear from 13 cSt to ~11.5 cSt with use, dropping from a 0W-40 to a 0W-30. This is commonly reflected in UOAs of common 0W-40 oils.

A 5W-40 starts with a more viscous base oil since it doesn't need to meet the 0W-xx rating. This means less VII is needed and thus will not shear as much with use.

 

[MaDMaXX]

Oh, so that's that whole "gap between winter and running temp" spec?

Alright, i did manage to find a UOA of the 0w40 on BITOG and saw it held it's viscosity well, so to be clear, you're talking about overall it will lose it through shear, or that it will temporarily lose it whilst being sheared?

How, does the higher HTHS rating affect that VII difference?

 

[kschachn]

Whether or not an oil will exhibit mechanical shear is highly dependent upon the engine design. From what we’ve seen on here very few engines have a significant problem in this specific area. It’s also dependent on the quality and type of the VII polymers used.

 

[ka9mnx]

SuperTech semi-syn 10w-40 has an HTHS of 3.99 and 100C cSt of 14.96 and it's API SP. Just sayin...

 

[ZeeOSix]

VII polymers are known to shear, meaning they lose viscosity under pressure.

Thought the VII polymers can shear both temporarily and permanently from being sheared, not from pressure - although shearing and pressure typically happen at the same time.

But if you simply put oil under pressure it's not necessarily shearing, which is when the layers of the oil are moving at different speeds. The shearing action is what effects the VII polymers. When the oil is sheared, the polymers will temporarily align which result in a temporary reduction in viscosity, but if the polymer chains are mechanically broken while being sheared, then the viscosity loss is permanent.

 

[ZeeOSix]

Oh, so that's that whole "gap between winter and running temp" spec?

The xW (W means Winter) viscosity spec is different than the xW-yy spec (yy = 20,, 30, 40, 50). The "W" spec is about cold starting flow and pumpability.

The yy in the oil grade is the KV100 viscosity ... the hot viscosity at 100 deg C.

KV40 is the viscosity at 40 deg C, and is used along with the KV100 to calculate the VI (viscosity index) number.

 

[ZeeOSix]

How, does the higher HTHS rating affect that VII difference?

HTHS is the viscosity (in cP) of the oil at 150 deg C while at a shear rate of 1,000,000/sec ... regardless of the amount of VII in the oil. HTHS is HTHS when defined at 150C & 1M/sec regardless of the oil's formulation. If you are comparing the HTHS of 10 different oils, then the one with the highest HTHS is most likely going to give the best MOFT. I would however, look for an oil with the highest HTHS and the lowest viscosity index (VI), because typically the lower the VI the less amount of VII additives will be in the oil. If an oil has way too much VII, then it may actually hurt the HTHS because of the high shear rate viscosity loss due to the VII additives. So a high HTHS oil probably will not have some crazy high viscosity index (VI).

Now if you sheared the oil at a much higher rate than 1M/sec then the amount of VII in the oil could cause the temporary shear viscosity (referred to as High Temp Full Shear, HTFS) to decrease even more compared to an oil with the same HTHS at (150C & 1M/sec).

Example:

This is getting deep in the weeds, and IMO not worth worrying about for a street car.

 

[MaDMaXX]

The xW (W means Winter) viscosity spec is different than the xW-yy spec (yy = 20,, 30, 40, 50). The "W" spec is about cold starting flow and pumpability.

The yy in the oil grade is the KV100 viscosity ... the hot viscosity at 100 deg C.

KV40 is the viscosity at 40 deg C, and is used along with the KV100 to calculate the VI (viscosity index) number.

This I understand, I was trying to refer to the gap, or difference between the winter rating and the hot rating, the larger the difference, the more VII needed to bridge the gap and the more potential for problems based on the rest of the info you posted.

 

[MaDMaXX]

Euro 0w40

View attachment 97321

I bought a couple of jugs of this for 25ea, seeing a good UOA of it holding it's viscosity over I think 6k miles was enough for me to be ok getting a 0w that I absolutely don't need.

Hopefully the rest of the specs are good.

 

[ZeeOSix]

This I understand, I was trying to refer to the gap, or difference between the winter rating and the hot rating, the larger the difference, the more VII needed to bridge the gap and the more potential for problems based on the rest of the info you posted.

Typically yes ... that's true. Look at the HTHS between a 5W-30 and a 10W-30 (same brand & flavor of oil) and typically the 10W-30 will have a slightly higher HTHS because it has less VIIs, so the temporary viscosity loss at the 1M/sec shear rate is slightly less.

 

[ZeeOSix]

I bought a couple of jugs of this for 25ea, seeing a good UOA of it holding it's viscosity over I think 6k miles was enough for me to be ok getting a 0w that I absolutely don't need.

Hopefully the rest of the specs are good.

That oil can do way more than what you're going to put it through ... nothing to worry about.

 

[wemay]

That oil can do way more than what you're going to put it through ... nothing to worry about.

%

 

[burgessdg]

Had a Fleet manager tell me once that he would never use an oil with a 30 point difference (specifically he hated 10W-40, which was very popular at the time). He stated in simple terms that the low number was generally the base oil, and they needed to add alot of Polymers to get it up to 40 hot. The more polymers the less resistance to shear. Always made sense to me. I never use an oil with more than a 25 point spread. The info in this post seems to back that up. Thanks.

 

[OVERKILL]

Had a Fleet manager tell me once that he would never use an oil with a 30 point difference (specifically he hated 10W-40, which was very popular at the time). He stated in simple terms that the low number was generally the base oil, and they needed to add alot of Polymers to get it up to 40 hot. The more polymers the less resistance to shear. Always made sense to me. I never use an oil with more than a 25 point spread. The info in this post seems to back that up. Thanks.

The number in front of the W is the Winter rating, which I tried to explain to you in the other thread, it is not a viscosity number. It's representative of the performance of the oil, measured via two different tests, at two separate temperatures 5C apart.

Using PAO, you can make an SAE30/10W-30 with no polymer at all.

Using some cheap Group II, you can also make a 10w-30 with significant polymer content; more polymer than a 5w-30 or even 0w-40.

It's a complex subject that people try to make simple rather than putting in the effort to understand it, which is unfortunate.

Probably the best way of describing the process is that you set your price point, then look at what base oils will work to meet the Winter rating you are shooting for. There can be multiple. Then you look at what your performance requirements are, limits such as volatility, and that'll help determine what you can get away with, and what you can't. Revise your price point as required.

Oil companies will spend the least amount of money possible to produce a product that performs as required. So, if they can use Group II and 15% VII to build their 15w-40 they will. But that doesn't mean oil company M won't build a 5w-40 out of PAO with only 8% VII polymer and slot it in their premium product line.

An example from Mobil, look at how the VM content changes depending on the base oil blend, and none of these oils have PAO in them:

Look at this 5w-30, it has 11.74% VM:

Now look at this 0w-30, it has 5.7%, and the 0w-40 has 9.4%:

This table shows some examples without Group III, you can see in this case, the 0w-40 has a majority 6cSt base and the 5w-30 only has 2.8% VM, compared to our earlier example:

Ergo, you can't just glance at the spread between the Winter rating and the grade at 100C and conclude, with certainty, that it has more or less VII polymer in it.