Previously was using Eneos Mineral 15W40.

I totally agree with you, API SM and SN do limit the phosphorus content 0.06-0.08% (API SL and SJ limit the content below 0.1%)

Phosphorus is a component of what is commonly recognized as an anti-wear agent and oxidation inhibitor, zinc dialkyldithiophosphate (ZDDP). ZDDP is very prevalent in the lubrication industry due to its excellent anti-wear and
antioxidant properties. Alternatively, larger quantities of volatile phosphorus contained in ZDDP have been linked
to premature poisoning of the catalyst surface of three-way catalytic converters....

Number of modern car models have ECU that monitor the functionality of the catalytic converters, early poisoning of catalytic converters will be a bad news.... some car ECU will respond by cutting power output...

However, eventhough with less anti wear agent, latest API SM and SN standards control average cam wear (sequence IVA) and allow maximum 90 micron (1/1000mm) of wear, whereas, in older standard, such as API SL and SJ, they allow maximum waer of 120 micron.....
You must understand the phosphorus level will deplete during operation, but API SN with Resource Conserving and ILSAC GF-5 would require the engine oil to retain minimum 79% of phosphorus during test....

From these info, I can summarize that eventhough latest API standards call for lower phosphorus content (lower anti wear agent), API actually commits to reduce wear on engine components... furthermore, API SN and SM fall under category of mid SAPS engine oil which is suitable to local fuel quality.....

Don't worry, engine produced after 1980's are mostly running on roller rocker arm, including G13B and G15B from the first generation Proton Saga....

I supposed VTW = Valve Train Wear, am I right?

According to American Petroleum Institute's (API) Engine Oil Licensing and Certification System,

- The Valve Train Wear, or known as average cam wear under engine Sequence IVA Test (ASTM D6891);

1) API SJ (for 2001 or older gasoline engine) and API SL (for 2004 and older gasoline engine) specify not more than 120 micron of wear, comparing with;

2) API SM (for 2010 or older gasoline engine) and API SN (current) specify not more than 90 micron of wear....

Even though newer API standards call for lower phosphorus content (anti wear agent) due to catalytic converter preservation, It does not allow more wear to take place, especially valve train wear.... With the help of new additive technology, API SN and SM must resist wear better than API SJ and SL which has higher content of phosphorus as anti wear agent...

For your infomation, current additive technology has enable the cam wear to be reduced down to 30 micron.

I think if the car we drive is not those sport car, highly modify car and high RPM driving habit, SM & SN is not the problem for that engine... Since ZDDP will decrease due to mileage driving, of course high RPM driving will cause it decrease faster.... Stick to the OCI and the suitable OIL Viscosity.... For my recommend, for Highway Drive more than City Drive, better choose Viscosity 40 for better engine protection, Viscosity 30 for City drive more than Highway Drive.

API SM controls Phosphorus (ZDDP) content at 0.06%min - 0.08%max.
No control of Phosphorus depletion

API SN controls Phosphorus (ZDDP) content at 0.06%min - 0.08%max.
API SM and SN has same amount of Phosphorus content (ZDDP).
futhermore,
API SN, with additional certification of Resource Conserving (RC) and ILSAC GF-5 will have control of Phosphorus depletion. The particular engine oil must retain minimum 79% of Phosphorus after test Sequence IIIGB (ASTM D7320).
But if you wish to use engine oil that will help in some fuel saving, you should look for

API SN, Resource Conserving and ILSAC GF-5
or
API SM, ILSAC GF-4

Plain API SM and SN (non Resource Conserving, non ILSAC GF-5) have no concern on Fuel Economy....

Local make cars, locally assembled cars, imported cars, local brands or oversea brands do fitted with catalytic converters and lambda O2 sensors. Proton Iswara LMSS and LMST ( produced after year 2000, now discontinued) are not fitted with catalytic converters.... Proton Wira since 1997 are fitted with catalytic converters...

Most cars on the road now are fitted with catalytic converters, you can remove it or modify the exhaust system to improve the power delivery. Without catalytic converter would allow you to use engine oil with higher Phosphorus (ZDDP) content such as API SL or SJ (less than 0.1% Phosphorus).

However,

Using API SL, SJ, with higher anti wear agent (Phosphorus, ZDDP) content does not protect engine better in term of wear because they allow maximum 120 micron of avg cam wear...

Comparing with;

API SM and SN which only allow 90 micron on the same aspect....

Now, looking at API SM and SN,
-They have same amount of anti wear agent (Phosphorus, ZDDP)
-They have same amount of allowance on cam wear

But those with additional certification of RC and ILSAC GF-5 on top of API SN will need to retain anti wear agent, this will make the engine oil to protect better....

Furthermore,

API SN is not always more expensive than API SM oil, you can also find some API SL oil are sold at higher price than API SN....

So ZDDP is not an issue
Fuel economy is not an issue
Catalytic Converter is not an issue
Price is not an issue

So why not upgrade yourself from API SM to SN?

You have nothing to lose but more to gain.... unless you have a valid contract to bind you to use API SM only

      API, as the name stands for; American Petroleum Institute, might sounds like it is only for the American... well, it is not....   , check this out-----

http://eolcs.api.org/companySearchResults....country&q=JAPAN

As you can see, many Japanese engine oil makers are certified API licensees....

If you are still not convinced and have doubts, then I would suggest you go for engine oil that has ILSAC standard

ILSAC is jointly developed and approved by Japan Automobile Manufacturers Association (JAMA), GM, Ford and Chrysler....meaning it is approved by all Japanese and American car makers....

Most car engine produced after 1980, whether it is made in USA, EU or JAPAN, are running on roller rocker arms...

All this info can be acquired in

http://www.api.org/

http://www.api.org/certification-programs/...aust-fluid.aspx

http://www.facebook.com/photo.php?fbid=480...&type=3&theater

http://www.facebook.com/photo.php?fbid=480...&type=3&theater

You have got it right!!     ,

API SN, Resource Conserving, ILSAC GF-5 oil will perform better in many aspects comparing with API SM GF-4.

     http://www.facebook.com/photo.php?fbid=480...&type=3&theater
So why still want to stick to API SM?

If you have some form of evidence, test result or experience that API SN has make more damage to engine comparing with API SM oil, by all means, for the sake of knowledge sharing, please let us know....

With this, we can write to API and ILSAC and question their integrity / reliability of their tests, make sure they take us, car owners, seriously and develop better standard to control engine oil makers' quality....

Dear joshuaa85, can share with us which brand of 0W/20 that you currently using and on what car?

You might have problem switching to Amsoil, let's take a look:



All Amsoil 0W20 grade gasoline engine oil are certified API SN.... I understand you do not want to use API SN oil, maybe you need to check out other brands which offer API SM for this grade...

I'm afraid I could not give a firm answer.
But I think in M'sia all ENEOS products are brought in by Mayshowa.
Anyone pls correct me if I'm wrong.

It is plastic bottle, so it is made in Thailand... no API "donut" nor "starburst" logos....  

"Starburst" is rare because basically ILSAC requirement is generally more stringent than common API service standard....

http://www.facebook.com/photo.php?fbid=480...&type=3&theater

http://www.facebook.com/photo.php?fbid=480...&type=3&theater

http://www.facebook.com/media/set/?set=a.4...18632696&type=3

 

Synthetic base oil makers and synthetic lubricants makers will be very sad reading your opinion....  

Actually, there are differences....

1) Temperature resistance (low VI): Regardless of how new/fresh the mineral oil in your engine, due to its nature of lower temperature resistance, it will provide less protection to engine moving parts...

2) Low saturation: Mineral base oil has higher content of volatile substances which are detrimental to the performance of the engine oil in terms of wear protection, oxidation resistance, corrosion control, shear stability and etc.....

In my opinion, shortening OCI for mineral oil might improve engine protection, but it would not be able to totally replicate engine protection at par with synthetic oil...