HTHSv and xw30 vs xw40 choice

[edyvw]

Originally Posted By: Benito
Originally Posted By: il_signore97
Also, don't take this the wrong way, I'm genuinely interested in the original question that you posed... However, I'm not sure what you're trying to get out of this thread, because there is no one on this forum that knows exactly why Porsche and Benz (AMG) decided to ban 30 grade oils. We will never know the exact and accurate reason, although we can all theorize forever...


We're theorizing either way.

But let me point one thing out. Seeing how many non Porsche, non AMG engines did get sludged on API xw30, why haven't those manufacturers specified xw40 only and avoided the problem entirely?

The overwhelming proportion of Euro vehicles, and therefore the biggest numerical risk of using an API oil with a significantly lower HTHSv, are the non AMG and Porsche ones. If the technical writers were concerned about a risk of using the wrong oil, just specify xw40 for all of them. Makes life a lot simpler for the customer and the mechanic.

As to your question on what am I trying to get out of this thread, it's simple. The current thinking is that HTHSv is more important than KV for engine protection. But it is entirely allowable for an xw40 for AMG vehicles (and maybe Porsche), to have an HTHSv of 3.5. So how does moving up to xw40 guarantee more protection?

We also know that Castrol Edge 0w30 & 0w40 are identical apart from the VII. So are we saying that more VII offers more protection for AMG & Porsche?

You are asking question that is already addressed in the numerous posts.
1. Porsche, AMG, BMW M, are much more expensive and under more stress. So manufacturers decided to be very specific. It is also part of marketing. When you are more strict on what goes in the engine, drivers get feeling of exclusiveness. When it comes to those cars, every single small detail plays role. Why? To make money, and with xW40, not to have bad press. Why? Ask them, you will not get definite answer here, you have to come up with your own best conclusion.
2. Other cars are less expensive, competing with cars that are cheaper. I already gave you example of VW Passat 1.8T. Buyer of AMG or Porsche 911 expects to pay a lot for a lot of stuff. Buyer of Passat before goes to buy Passat contemplates whether oil change is $70 or $80. So you have to make car more affordable. That can lead to various problems, but NA market is specific. We come back to appliance vs. car issue.
3. You are looking here for 100% definite answer. You will not get it.

 

[Benito]

The numerous posts you refer to are your own. You gave the same answer several times and just did so again. I got your point the first time and didn't agree with it then nor the next several times you repeated it.

Do you even realize that the minimum HTHSv for a 0w40 or a 5w40 or even a 10w40 is 2.9, the same for a 30? So there is no guarantee of getting enough HTHSv with an xw40 unless you go for a 15w40.

So in your "logic" they state the use of an 0w40 or 5w40 to preclude the user from using a too thin HTHSv API xw30, but this actually doesn't guarantee they get a sufficiently thick HTHSv in their xw40 anyway.

That, together with the fact that they clearly state that oil must meet a particular specification and mention the xw40 thing in small print, tells me where their emphasis is ie use a specified oil, with the proviso that it should be xw40 if it is a particular engine.

Your reasoning is not logical nor persuasive.

So I'll continue this thread especially since nobody has expanded on my point about Castrol 0w30 and 0w40 being the same oil with the 0w40 simply having more VII.

 

[userfriendly]

VII cost more than base oil, which could explain one oil
costing more than the other.

My guess is you are right.
But, the 0W40 may have a lower BOV than the 0W30 and a higher
percentage of VII than we could ever imagine.

Maybe the AMGs run hot enough to evaporate the low boilers
in 0W40, so as it shears it also stays in grade.

Now go find two people.
One who knows and another who cares.

 

[Benito]

Originally Posted By: used_0il
Now go find two people.
One who knows and another who cares.


LOL.

On this oil site, we speculate without knowledge let alone facts on all sorts of topics, and then when someone comes along with an oil question that calls for some theorizing based on oil knowledge, that's the response!

We can't find two people here?

Having said that, thanks to Shannow for his responses.

 

[Quattro Pete]

Originally Posted By: Benito
Do you even realize that the minimum HTHSv for a 0w40 or a 5w40 or even a 10w40 is 2.9, the same for a 30?

That is not correct today. That's how it used to be long time ago, but some years back this got updated. Now, 0w-40, 5w-40, and 10w-40 require a minimum HT/HS viscosity of 3.5 cP. 15w-40 requires 3.7 cP.

 

[Benito]

You are right! I should have checked a more up to date J300 chart.

Looks like they changed it in Nov 2007.

 

[Garak]

Originally Posted By: il_signore97
However, I'm not sure what you're trying to get out of this thread, because there is no one on this forum that knows exactly why Porsche and Benz (AMG) decided to ban 30 grade oils. We will never know the exact and accurate reason, although we can all theorize forever...

There is one, at the very least, who may know. He just hasn't posted in the thread.

 

[Quattro Pete]

Originally Posted By: Benito
Looks like they changed it in Nov 2007.

Correct.

http://standards.sae.org/j300_200711/

 

[il_signore97]

Originally Posted By: Benito


We're theorizing either way.


Yes, fair enough!

Originally Posted By: Benito


But let me point one thing out. Seeing how many non Porsche, non AMG engines did get sludged on API xw30, why haven't those manufacturers specified xw40 only and avoided the problem entirely?


Which engines / manufacturers are you referring to specifically. I get the sense that you're referring to non-Euro makes such as the Toyota sludge monsters, Chrysler 2.7L, and other such examples (etc, etc). I guess you can also include the VW 1.8T and some BMW N/A inline 6's in there as well. If that is in fact what you're referring to, I disagree with your above statement. I think there are only 2 reasons why these engines historically got sludged:

1) The owners inadvertently used a conventional oil for an OCI that was too long, or ignored the recommended OCI's all together.

2) There are/were design flaws with those engines.


Originally Posted By: Benito

The overwhelming proportion of Euro vehicles, and therefore the biggest numerical risk of using an API oil with a significantly lower HTHSv, are the non AMG and Porsche ones. If the technical writers were concerned about a risk of using the wrong oil, just specify xw40 for all of them. Makes life a lot simpler for the customer and the mechanic.


Again, I disagree with your opinion on the above. The bulk of the Euro engines are NOT the greatest risk because they don't represent the ones that are the harshest on the approved oils. Like in the example which I provided previously (and you ignored), the normal "pedestrian" Euro engines such as BMW's non-turbo, non-DI inline 6's and the Benz M272 V6 engine family, they are the LEAST at risk of being damaged by a typical non-Euro, API SN 5W30. My engine (M272E30) takes 8.5 qts of oil, and has a large oil/coolant heat exchanger. In reality, for typical North American use, as long as I grab "any" synthetic 5W30 oil, the engine should outlast the body that surrounds it. I'm not suggesting that anyone does that, nor do I do that, but my point stands.

Further to the above, BMW actually has an LL-01 FE specification that allows xW30 grade oils in some engines that have an HTHS minimum of 2.9, not the typical 3.5. Again, this shows that these more "sedate" engines have very little risk of running a non-Euro oil, as long as it is up to task for the longer drain intervals (read synthetic).

It's the AMG and highly stressed engines that are higher risk here, IMO. You can ignore this point of view all you want, but the facts are clear, and it's not hard to come to this conclusion (rightly or wrongly).

Originally Posted By: Benito


As to your question on what am I trying to get out of this thread, it's simple. The current thinking is that HTHSv is more important than KV for engine protection. But it is entirely allowable for an xw40 for AMG vehicles (and maybe Porsche), to have an HTHSv of 3.5. So how does moving up to xw40 guarantee more protection?

We also know that Castrol Edge 0w30 & 0w40 are identical apart from the VII. So are we saying that more VII offers more protection for AMG & Porsche?


Well, it was one specific member's thinking that HTHS was more important than KV in an engine. In some cases (such as bearings and ring pack), this is likely true. But as Shannow suggested, it may not be true in all places. I can't add much more to that either way.

As for Castrol 0W30 and 0W40, they are not identical except for VII when it comes to specifications. The 0W30 has an HTHS of pretty much 3.5 right on, but the 0W40 has an HTHS of 3.7 (3.8???). One HTHS is higher than the other, so as you can see, not the same in the engine bearings, regardless of how they are made and other similarities that they share.

As I said, I'm genuinely interested in this topic / discussion. Let's keep this civil so it can continue on (and perhaps Mr. Hillary himself may add to this thread as Garak suggested!)

 

[userfriendly]

Question period 101;

Why boost KV100 with VII if the HTHS is not proportionately elevated?

If you build it will they come, the price point of an engine oil.

Lubricants likely exist that could be factory filled for the
life of the vehicle including engine oil.

Would the vehicle require filter changes and scheduled additive supplements?

 

[Benito]

Originally Posted By: il_signore97
Which engines / manufacturers are you referring to specifically. I get the sense that you're referring to non-Euro makes

OK. Sorry for not being clearer. I was talking about Euro engines from BMW, Mercedes, VW/Audi. I am limiting this entire discussion to Euro standards in excess of HTHSv=3.5 where the manufacturer nevertheless distinguishes between xw30 & xw40.


Originally Posted By: il_signore97
The bulk of the Euro engines are NOT the greatest risk because they don't represent the ones that are the harshest on the approved oils. Like in the example which I provided previously (and you ignored), the normal "pedestrian" Euro engines such as BMW's non-turbo, non-DI inline 6's and the Benz M272 V6 engine family, they are the LEAST at risk of being damaged by a typical non-Euro, API SN 5W30. My engine (M272E30) takes 8.5 qts of oil, and has a large oil/coolant heat exchanger. In reality, for typical North American use, as long as I grab "any" synthetic 5W30 oil, the engine should outlast the body that surrounds it. I'm not suggesting that anyone does that, nor do I do that, but my point stands.

Further to the above, BMW actually has an LL-01 FE specification that allows xW30 grade oils in some engines that have an HTHS minimum of 2.9, not the typical 3.5. Again, this shows that these more "sedate" engines have very little risk of running a non-Euro oil, as long as it is up to task for the longer drain intervals (read synthetic).

It's the AMG and highly stressed engines that are higher risk here, IMO. You can ignore this point of view all you want, but the facts are clear, and it's not hard to come to this conclusion (rightly or wrongly).

OK, so there are some engines, specified for xw30, that don't need a HTHSv of 3.5. But who are we to know for sure that they will be ok with HTHSv as low as 2.9 especially with longer change intervals, different climates, lower fuel quality? 3.5 to 2.9 is a big drop.

Also consider that over time, non AMG engines end up with the same power output as the AMG engines of a few years earlier. (However, I would concede that AMG engines are built differently).

And what about the increasing number of large and medium size engines with twin turbos that allow xw30. Maybe they meet your definition of "highly stressed" as well?

Also, I'm certain that there have actually been problems using API M1 5w30 in Euro turbo vehicles that specify HTHSv of 3.5.

As to whether AMG engines are more at risk here, in the US, let's think about that for a while. Since they have even more power than non AMG engines they are less stressed in daily driving. They are only really stressed when driven hard. They won't be stressed on the freeway for example. But because they are AMG vehicles, just like M vehicles, just as with those variants of the Mustang, if they are driven hard, which is a more likely occurrence, then they need the xw40 because anything less than a HTHSv of 3.5 won't cut it. But if that is the case wouldn't the same be true of the non AMG vehicles then? All the fun, smaller engine BMWs and Audis. A Golf GTi. Which Euro vehicle, specified for xw30, would get away with being driven hard on API 5w30?


Originally Posted By: il_signore97
As for Castrol 0W30 and 0W40, they are not identical except for VII when it comes to specifications. The 0W30 has an HTHS of pretty much 3.5 right on, but the 0W40 has an HTHS of 3.7 (3.8???). One HTHS is higher than the other, so as you can see, not the same in the engine bearings, regardless of how they are made and other similarities that they share.

What's the source of that information? Is that for the latest two versions? I thought Castrol only said ">3.5".


Originally Posted By: il_signore97
Let's keep this civil

No problem but I'm not sure what prompted that request!

 

[glxpassat]

I think what's missing here is the realization that oils in an engine are rarely going to get to 150c where the HTHS spec is measured, where a 30w and 40w with the same HTHS would have equal viscosity. If the oil stays closer to 100c most of the time, the 40w is going to be thicker than the 30w.

I read many years ago, somewhere, that when Porsche tore down the engines and made measurements, there was more bearing wear with 30w so they moved away from it.

 

[Jetronic]

Oils do get to 150°C, inside the main or big end bearings, and inside the turbo (if any) or around the exhaust valve stems.

Also on the piston rings 150°C is easy to obtain, especially above the oil control ring.

 

[glxpassat]

The oil may get to that temp while inside a bearing or turbo, but it's not that high when it enters. A 40w is going to be thicker when it enters, so for however long it's in a bearing, it's average viscosity will be higher.

 

[Jetronic]

no it gets that high in the part of the bearing that's carrying a load., incidentally that's also where the highest shear force is.

you'd get less leakage with a 40w compared to a 30w of the same HTHS, and probably slightly higher oil pressure as a result.

 

[Shannow]

Originally Posted By: glxpassat
I think what's missing here is the realization that oils in an engine are rarely going to get to 150c where the HTHS spec is measured, where a 30w and 40w with the same HTHS would have equal viscosity. If the oil stays closer to 100c most of the time, the 40w is going to be thicker than the 30w.


Jetronic is correct.

When they found that multigrades weren't working as advertised through KV alone, and found that the high shear viscosity was considerably lower than the KV, they didn't choose 10^6 shear rate and 150C because the numbers sounded nice, or pluck them from their freckle.

The figures are representative of the shear rates in bearings, and the temperatures attained there...that's why they were chosen, and that's why the arguments that people "must remember" that HTHS is tested above bulk oil temps are wrong.

Bearing sees HTHS.

On the pressure face of the bearing always, and at speed all around.

 

[glxpassat]

But wouldn't it be safe to assume that the HTHS test criteria is based on the harshest expected conditions? IE, high speed/high load? Maybe it doesn't get that hot or sheer that bad when cruising at 40 mph under light throttle... If that's the case, the 40w should offer a little more protection than the 30w in every day driving, especially in a car with a clutch where there can be more shock to the bearings than with an auto tranny.

 

[il_signore97]

Originally Posted By: Benito


Originally Posted By: il_signore97
As for Castrol 0W30 and 0W40, they are not identical except for VII when it comes to specifications. The 0W30 has an HTHS of pretty much 3.5 right on, but the 0W40 has an HTHS of 3.7 (3.8???). One HTHS is higher than the other, so as you can see, not the same in the engine bearings, regardless of how they are made and other similarities that they share.

What's the source of that information? Is that for the latest two versions? I thought Castrol only said ">3.5".




This was stated on the forums here when the Castrol 0W40 started to appear in North America. I think it was bobbydavro that spoke about it -- he appears to either work for Castrol or has close ties with them somehow, but I can't say for sure.


In terms of the rest of the topics discussed here, I don't think I can add much more to this as I've stated all of my opinions/theories and other facts that I know, but I will sit back and see what else comes out of this. I still believe the reason why an xW40 is specified for AMG vehicles and Porsche vehicles is to ensure that a correct oil is applied to them, and maybe also to give more headroom for shear over an OCI (since it has been established that "most" xW40 oils will have HTHS values greater than xW30 oils, even though both must have a min HTHS of 3.5).

Maybe Shannow can think of any other strictly technical reasons of why an xW40 is better than an xW30 given that both would have to have a minimum HTHS of 3.5?

 

[Olas]

Originally Posted By: il_signore97

Maybe Shannow can think of any other strictly technical reasons of why an xW40 is better than an xW30 given that both would have to have a minimum HTHS of 3.5?


I agree with most of your post except for the part above. Regardless of 30 or 40, A1/B1 and A5/B5 both specify minimum 2.9 and maximum 3.5, only A3/B3 and A3/B4 are minimum 3.5

 

[DS9]

Excellent point.

***

First post here (below) is wrong.
Originally Posted By: Benito
HTHS viscosity is more important than grade.
The Euro oils must all have a minimum HTHSv of 3.5 regardless of if they are xw30 or xw40.


Some europian oils (oils for european cars) have minimum HTHS of 2.9 mPa.s.

Page 5 http://www.acea.be/uploads/publications/2010_ACEA_Oil_Sequences.pdf

C1 Stable, stay-in-grade oil intended for use as catalyst compatible oil in vehicles with DPF and TWC in high performance car and light van diesel and gasoline engines requiring low friction, low viscosity, low SAPS oils with a minimum HTHS viscosity of 2.9 mPa.s. These oils will increase the DPF and TWC life and maintain the vehicles fuel economy.
Warning: these oils have the lowest SAPS limits and are unsuitable for use in some engines. Consult owner manual or handbook if in doubt.

C2 Stable, stay-in-grade oil intended for use as catalyst compatible oil in vehicles with DPF and TWC in high performance car and light van diesel and gasoline engines designed to be capable of using low friction, low viscosity oils with a minimum HTHS viscosity of 2.9mPa.s. These oils will increase the DPF and TWC life and maintain the vehicles