0W-20 in a BMW M-60

[Shannow]

Originally Posted By: Gokhan
The question here was whether lower MRV/CCS necessarily means lighter oil when the engine is cold.

The answer, as implied by CATERHAM, is no. For a given y of *W-y SAE viscosity grade, how light an oil when it's cold is given by the viscosity index, not MRV/CCS. Higher the viscosity index, lighter the oil will be when it's cold.


The implication that VI trumps cold pumping for cold pumping is false...the implication that VI in any reasonably chosen oil has marked advantages similarly false.

API have chosen pumpability precisely because that is what they are trying to simulate.

I can get a 5W-30 with a 192VI down here, which some on this board would tell you has better extreme cold performance than a 0W-30...by extreme, temperatures that aren't 40C(ish)

 

[CATERHAM]

Originally Posted By: Shannow
..the implication that VI in any reasonably chosen oil has marked advantages similarly false.

Well that's a clearly false statement.
It has everything to do with typical non-extreme start-up temp's which is why the OEM's are the main drivers of high V.I. oils.

 

[Shannow]

Aside form the "huge" (but until now unquantifiable by yourself) increase in fuel economy between the period that oil is flowing and warm-up...what are the marked advantages.

You seem to discount pumpability againt VI, when there's a whole standard's board that think differently...

What are the marked advantages to VI ?

Especially the shear prone ones ?

When the OEM literature points solely to CAFE, fuel economy, and carbon emissions, not wear...

 

[CATERHAM]

So let me get this straight, you don't like M1 0W-40 (VI 185) and you prefer it's lower VI (heavier on start-up) competitors.

 

[Gokhan]

Let's not forget that "pumpability" for 0W- or 5W- is only a concern at very deep freezing temperatures. So, yes, if you live in a very cold state, that's important. I was talking about more common cold temperatures, such as above freezing and during engine warm-up.

Despite what some people might think, viscosity-index improvers are usually not a bad thing at all. Don't forget that viscosity-index improvers also improve the wear protection in the elastohydrodynamic-lubrication regime, as they have certain properties that the base oil doesn't have. So, to say that viscosity-index improvers increase wear is not a true statement.

They also come in various quality levels, some more shear-stable than others. If an oil is not showing large shear in UOAs and you aren't seeing excess engine deposits or sludge, the viscosity-index improvers are contributing positively to the performance of the oil.

 

[Shannow]

Originally Posted By: CATERHAM
So let me get this straight, you don't like M1 0W-40 (VI 185) and you prefer it's lower VI (heavier on start-up) competitors.


Where on Earth did you make that up from ?

Show me a quote, rather than making stuff up. You've accused me of hating M1 0W-40 multiple times, none of which you can back up...it's one of my favourites.

So you would prefer a 192VI 5W-30 over a 0W-30 ?

 

[edyvw]

In my practical application, GC with lower VI proved better during cold weather then M! with higher VI.
Paper is one thing, practice completely another.

 

[bobbydavro]

It's far mor complex than made out. No OEM even cares for VI, they want real proof of performance in engine test. Hence they spend so much effort developing them.

Viscosity improves are rubber. They don't burn cleanly and contribute to piston deposits.

 

[bobbydavro]

Originally Posted By: edyvw
In my practical application, GC with lower VI proved better during cold weather then M! with higher VI.
Paper is one thing, practice completely another.


That's because one is better in the cold. And 40C isn't cold

ACEA 2012 and API SN have introduced aged oil pump ability performance.

Also if we have a fixed kv40 with two oils and one has 200VI and one is 150VI, which will offer best fuel economy ?

 

[CATERHAM]

Originally Posted By: Shannow
Originally Posted By: CATERHAM
So let me get this straight, you don't like M1 0W-40 (VI 185) and you prefer it's lower VI (heavier on start-up) competitors.


Where on Earth did you make that up from ?

Show me a quote, rather than making stuff up. You've accused me of hating M1 0W-40 multiple times, none of which you can back up...it's one of my favourites.

So you would prefer a 192VI 5W-30 over a 0W-30 ?

The conclusion that you don't like M1 0W-40 is a question which naturally follows from your statements about VI and polymer VMs generally.

The shear stable Sustina 5W-30 has a VI of 194 so yes in my climate I would definitely prefer it to any commercially available light 0W-30. Of course I would still prefer a blend of M1 0W-40 and TGMO 0W-20 which is is cheaper and results in 200+ VI.

 

[Shannow]

It wasn't a question, that you asked, it was a statement that you made, have made previously, and as usual...have made up

 

[bobbydavro]

Originally Posted By: CATERHAM
Originally Posted By: Shannow
Originally Posted By: CATERHAM
So let me get this straight, you don't like M1 0W-40 (VI 185) and you prefer it's lower VI (heavier on start-up) competitors.


Where on Earth did you make that up from ?

Show me a quote, rather than making stuff up. You've accused me of hating M1 0W-40 multiple times, none of which you can back up...it's one of my favourites.

So you would prefer a 192VI 5W-30 over a 0W-30 ?

The conclusion that you don't like M1 0W-40 is a question which naturally follows from your statements about VI and polymer VMs generally.

The shear stable Sustina 5W-30 has a VI of 194 so yes in my climate I would definitely prefer it to any commercially available light 0W-30. Of course I would still prefer a blend of M1 0W-40 and TGMO 0W-20 which is is cheaper and results in 200+ VI.


Why is it more shear stable? And why is VI so important. I notice you haven't answered my question and I'd be interesting to see what sort of mess you have mixing PMAs with XOMs polymer and ppds.

High VIs like that use PMAs which offer poor shear stability and also need high polymer solid treat levels vs other VMs, on wider grades his can cause deposits and it why you never see much above 190 Vi on products with ACEA specifications, let alone much tougher OEM specs

 

[CATERHAM]

Originally Posted By: Shannow
It wasn't a question, that you asked, it was a statement that you made, have made previously, and as usual...have made up

No, it's a supposition based on statements you've made.

 

[Garak]

Originally Posted By: Gokhan
Also note that lower MRV/CCS also results in lower NOACK, which translates into a lower quality oil as far as normal operating temperature is concerned.

How does low NOACK translate into a lower quality oil?

 

[edyvw]

Originally Posted By: Garak
Originally Posted By: Gokhan
Also note that lower MRV/CCS also results in lower NOACK, which translates into a lower quality oil as far as normal operating temperature is concerned.

How does low NOACK translate into a lower quality oil?

I was of same question, but pointless to ask!

 

[Gokhan]

Higher NOACK is correlated with increased high-temperature deposits.

If I said lower, it was a typo. I meant lower MRV/CCS results in higher NOACK.

 

[bigjl]

Originally Posted By: CATERHAM
Originally Posted By: bobbydavro

I'm saying going thinner than a 10W-60 wouldn't be a good idea in something like an M3. As to why, I pointed out some of the fuel and water dilution issues in an earlier post, plus the bearings in this engine need a high film thickness. The 10W-60 is about 5.2 HTHS. The same applies to the M60 regarding ignoring OEM recommendations and trying to correlate film thickness to viscosity

Some 30 grades are thicker ( have higher base oil viscosity than other 40 grades).

My point still stands regarding film thickness being more critical. Some industry wear tests become less severe when you run them cooler as the film thickness increases and negates the fact the ZDDP isn't working

As long as the oil gets to the journal bearings within a second or two and the low pressure light goes there is no real need to read into the viscosity grade too much, certainly not enought to ignore the 3.5cP min HTHS BMW specify in this engine. Just because it's colder doesn't mean you can drop viscosity

And you're 100% wrong.
Because it's cold is EXACTLY why you can run a lighter oil and that includes oil with a HTHSV rating well below 3.5cP.
It's all about operational viscosity and the viscosity in every part of an engine correlates to the sump oil temp's.
The reason the European manufacturers have moved away from specifying 20 grade and light 30 grade oils for low ambient temperature conditions (they all used to) is because synthetic oils made it possible to specify a heavy 30 grade oil (min' 3.5cP HTHSV) and heavier 0W-XX oils for year round use.
This made it impossible for some clueless owner who still had a 20 grade oil in the sump from the winter to run his BMW or Porsche flat out on the autobahn in the summer with resulting increased engine wear or worse.

The fact remains that you can still very much benefit from running a 0W-20 (HTHSV 2.6cP) oil in sub-freezing conditions in any high performance car during the winter months.
As I've pointed out before in this thread, your engine can't tell the difference between a 0W/5W-30 (HTHSVv 3.5cP) at 100C oil temp's and a 0W-20 (HTHSV 2.6cP) at 85C. They both nominally have the same operational viscosities. The big difference is on start-up and during warm-up where your engine will very much appreciate having the much lighter 0W-20 oil in the sump.


Since when did anybody in Europe put -w20 oil in their engine for winter?

The only widely available 5w20 oil of late is the one by Castrol for the 1.0 Ecoboost engine which is a Professional branded oil and only really available from Ford dealers.

You can also get the -w20 oil required by the V8 petrol Land Rovers and Jaguars with the 5.0 engine, can't remember if it is a 0w20 or 5w20 too be honest.

 

[edyvw]

I never heard anyone putting W20 oil in Europe. I am not sure whether I saw it ever on the shelfs.

 

[fpracha]

Originally Posted By: CATERHAM
Originally Posted By: fpracha
Between a 5w40 grade with a higher MRV value but lower HTHS(=3.59) and a 0w-40 grade with a lower MRV value and higher HTHS(=3.80), which one exactly is the "lighter / thinner" oil... the one with a lower HTHS OR one with the lower MRV and CCS values ?
That depends entirely on what temperature your making the comparison.
It also depends on the VIs of both oils.
But assuming the 5W-40 has a lower VI it will likely be heavier at all start-up temp's up to at least 80F.

thanks this is helpful... but does it imply that this given 0w-40 will have more oil consumption (even though a cleaner engine & less deposits) compared to this 5w-40 oil ?
Could this 0w-40 oil lead to a higher engine wear at some special operating conditions ?
OR
does this 0w-40 vs. this 5w-40 oil guarantee lowest higher engine wear at all temperatures and all operating conditions of high load slow speed driving a.k.a lugging type engine operation ?

Originally Posted By: Gokhan
The question here was whether lower MRV/CCS necessarily means lighter oil when the engine is cold.

The answer, as implied by CATERHAM, is no. For a given y of *W-y SAE viscosity grade, how light an oil when it's cold is given by the viscosity index, not MRV/CCS. Higher the viscosity index, lighter the oil will be when it's cold.

MRV/CCS only tells you about the lowest possible engine-cranking temperature.

Also note that lower MRV/CCS also results in lower NOACK, which translates into a lower quality oil as far as normal operating temperature is concerned. So, there is a trade-off between MRV/CCS and performance at normal or high operating temperature. One can always use a higher-quality base stock to keep the MRV/CCS and NOACK both low, but there is still a trade-off within a given base-stock type.

Are you saying this because of higher oil consumption from the low MRV/CCS and higher NOACK oil ?
What exactly do you mean by "lower quality oil" ?

 

[fpracha]

Originally Posted By: bobbydavro
Originally Posted By: CATERHAM
The shear stable Sustina 5W-30 has a VI of 194 so yes in my climate I would definitely prefer it to any commercially available light 0W-30. Of course I would still prefer a blend of M1 0W-40 and TGMO 0W-20 which is is cheaper and results in 200+ VI.
Why is it more shear stable?
High VIs like that use PMAs which offer poor shear stability and also need high polymer solid treat levels vs other VMs, on wider grades his can cause deposits and it why you never see much above 190 Vi on products with ACEA specifications, let alone much tougher OEM specs

you are making this interesting now... can you show some proof or UOAs where PMA containing xW-20/30 oils have sheared more than the older VM technology oils ?

Otherwise why on are PMAs the more costly VM today ?