See post #80.
0W20 for good protection?
- Thread starter CarfriendXX
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So the automatically determined location affects the owner's manual or underhood sticker for grade? Or does it flash a warning to the operator that they have used an improper one? If it did that, how would it know? And are only the cars sold outside the US equipped with this warning?
Or does it affect the engine operation in some way? If it does that then what's the problem?
This is silly on so many levels besides technical ones that it's actually difficult to discuss in a rational manner. The logistics of this and the implementation would be enormous. Not to mention the massive global conspiracy that is required.
OVERKILL
$100 Site Donor 2021
What engine oil pump is viscosity dependent? Are these prohibited from being sold in Winnipeg because it gets below -40C and oil will be far thicker than the engine will ever see in Florida?
An oil pump that is viscosity dependent? What's the really mean. PD oil pumps have less slip and pump more efficiently with thicker oil.
If you mean 6 mm^2/sec (which is 6 cSt), thats' in the 12 to 16 KV100 range. Only engines specified for xW-16 or less should be running that thin of oil. And actually, viscosity (HTHS and MOFT) means a lot. Go too thin and engine wear will increase significantly. Lots of tribology studies show the relationship between HTHS and wear.
Temperature in and of itself is irrelevant here. It is the film thickness which is important at any given temperature. Synthetic or not isn't relevant.
You're making up more and more to try and support a physics house of cards. Where are you pulling this from exactly?
When PD pumps become "viscosity dependent" they decide to open up the relief valve.
Exactly. It is beyond idiotic to think an oil has one viscosity regardless of temperature. The variation is enormous in your example above.
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Oil pumps with viscosity-dependent delivery capacity are used at VW, among others. But sorry, I'm keeping a low profile, I have no idea. Theories are simply created here, a lubricant today lives more on additives than viscosity itself. Where does the biggest wear occur again? Right at the cold start. But I have taken note of your opinion, I see it a little differently. For me, the topic is through.
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OVERKILL
$100 Site Donor 2021
It sounds more like you are describing variable displacement oil pumps, some of which modify their delivery profile based on engine load and temperature.
No it doesn’t. And even if it did you would want the oil film as thick as possible, not thin. MOFT is what prevents wear not the other way around. People are always getting that reversed.
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Your big mistake is, in tribology there is no better through thicker oil. That's mainstream thinking and wrong. A cold start is 259 kilometres of highway wear and tear. Every expensive sports car would be travelling with the thickest oil. They don't, not even in racing, and yes they still hold what a miracle. But before you throw in again that these engines are revised, you are welcome to recommend taking the thickest oil, I don't do that
Sorry but this is exactly reversed. There are actually no benefits to thinner oils except fuel economy, only drawbacks. Your comment about racing illustrates your ignorance here because that has a far different objective than passenger car usage. You simply do not have a clue about any of this and are pulling things out of the air without not knowing the meaning or reasoning.
Next stop you’ll have those variable viscosity oil pumps on race cars to reduce startup wear. You’re just posting things you’ve found on the Internet somewhere but you don’t have any technical knowledge to know whether any of it is true or if it only applies to some specific or narrow aspect of a larger whole. Combine that with misunderstandings about physics and design and this is what you get.
OVERKILL
$100 Site Donor 2021
You seem to be intentionally torpedoing the nuance here.
Per your assertion: "Every expensive sports car would be travelling with the thickest oil. They don't, not even in racing,"
Well, for the longest time BMW's M-cars called for 10W-60. Ford's GT and all of their performance engines call for 5W-50. GM called for 15W-50 in the Corvette and Camaro if you were racing them. The SRT HEMI's all call for 0W-40 (as does the current Corvette) while their more pedestrian siblings call for 0W-20. Many of the Euro marques like Porsche were already using 0W-40. Have you checked the oil requirements for a Ferrari?
So yes, a lot of expensive sports cars do in fact call for heavier oils.
On the "cold start" you stated: "Where does the biggest wear occur again? Right at the cold start"
Do you know why exception was taken to that statement? It's because it again doesn't adequately address the nuance of what transpires, which should really be called "warm-up wear", which may give you a hint as to there being additional mechanisms in play that result in increased wear while the engine and oil are not up to temperature.
Yes, that warm-up wear occurs for a reason distinct from and not due to the MOFT.
You obviously don't understand the tribology going on in an engine. Most sports cars like Corvette, Mustang, etc DO specify thicker oils ... for a reason, to give more engine protection in more demanding use conditions. That only happens from using higher viscosity/HTSH oil and obtaining more MOFT.
Personally think it is simple. What is complicated is second guessing why there is different oil viscosity grades around the world on the same engine. So… why? Although that viscosity affects a lot in an engine. Mazda ships all non-turbo with high moly 0w-20 from the factory in Japan to the whole world. The OM says what oil to use where it is shipped.
Canada, USA and Puerto Rico 0w-20, Mexico 5w-30
https://www.mazdausa.com/static/manuals/2019/mx5/contents/07030400.html
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When engineers are not cowering because of CAFE, then they specify oil viscosity that best protects the engine. That's why the same engines used in different countries call out a whole spectrum of oil viscosity based on the ambient temperatures the vehicle is used in.
All that viscosity affects a lot in the engine? Do you have any idea what you’re talking about here?
Because the OM states what viscosity to use… Come on. You are a very far second place on ideas why.
Any modern engine will show ambient temperature and the oil viscosity recommended. Notice that all viscosities are recommended at the same high ambient temperature.
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OVERKILL
$100 Site Donor 2021
It's a combination of local market availability and a lack of CAFE, not some grand conspiracy with GPS tracking that affects ECM programming based on oil grade.
One of the stipulations of US CAFE regulations is that only the oil used for CAFE testing can be recommended for use. Some OEM's skirt this a bit with verbiage like what has been used by GM, who would state that on the race track, to use 15W-50, but to go back to 5W-30 for the street. Toyota has made vague references to a heavier oil being "more suitable" under demanding conditions, but never called out a specific grade.
Prior to CAFE regulation, manuals used to have viscosity charts with a range of acceptable viscosities listed. These are often still present in other parts of the world.
Canada always follows the US, so we have the same setup as you do. Mexico is Mexico, it's hot, 5W-30 is likely far more readily available and there's no CAFE mandate so Mazda can spec something different, based on those factors. It's that simple.
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