Amsoil 0W-40: AZF vs. EFO

[Falcon_LS]

I'm trying to get a clearer understanding of the additive packages of Signature Series 0W-40 (AZF) and the European Car Formula 0W-40 Full SAPS (EFO).

From what I can gather:

Signature Series 0W-40 (AZF):

• Seems primarily focused on North American specs: API SP, GM dexos R, Chrysler MS-12633 (and Nissan GT-R).
• Boasts a high TBN of 12.5.
• No explicit ACEA claims are listed.
• Strong emphasis on LSPI protection and turbo protection, often citing tests based on GM dexos1 Gen 2 (though sometimes using their 5w30 for specific claims).

European Car Formula 0W-40 Full SAPS (EFO):

• Clearly targets European OEM specs: ACEA A3/B4, BMW LL-01, MB 229.5, Porsche A40, VW 502.00/505.00.
• Has a TBN around 10.1.

This has me wondering:

• AZF has a very high TBN (12.5) compared to EFO (10.1), very similar to Mobil 1 FS 0W-40 (SN). Does this imply a significantly more robust or different type of detergent package in AZF?
• How might their dispersancy characteristics differ based on their target applications (e.g. sludge protection for extended drains in AZF vs. handling soot in Euro diesels for EFO, though EFO is also for gasoline applications)?

I'm trying to understand if AZF is more of a robust API SP oil with some European like stats (HTHS and TBN) or if its additive package has more fundamental similarities/differences to a dedicated European Full SAPS oil like EFO, beyond just the listed approvals. Thank you!

 

[buster]

Noack is better for the AZF. It also contains a nice ester cobase.

Due to Euro restrictions, they didn't use the ester cobase in the Euro grade.

Higher ZDP levels for the Euro 0w40.


VOA of Amsoil Euro 0w40 EFO

VOA of AMSOIL Signature Series AZF

 

[Subiesquad87]

The euro formula aims to meet European car specs, while both are an excellent oil the euro specs can be quite narrow which limits the amount of additives that can be used in the formulation. This is part of the reason an ester base stock isn’t being used in the euro formulation. That coupled with other additives in the SS formulation would bring it out of tolerance. This isn’t necessarily a bad thing per se but many believe the SS formulation is better overall. It really depends on what your goals are and what your application is.

The best way to look at it in my opinion is with the euro formulation amsoil is looking to meet euro specifications. With signature series amsoil is trying to make the best possible oil, they don’t have to live within a certain spec so they can use whatever they see fit to make the best possible product.

 

[scrllock]

The euro formula aims to meet European car specs, while both are an excellent oil the euro specs can be quite narrow which limits the amount of additives that can be used in the formulation. This is part of the reason an ester base stock isn’t being used in the euro formulation. That coupled with other additives in the SS formulation would bring it out of tolerance. This isn’t necessarily a bad thing per se but many believe the SS formulation is better overall. It really depends on what your goals are and what your application is.

The best way to look at it in my opinion is with the euro formulation amsoil is looking to meet euro specifications. With signature series amsoil is trying to make the best possible oil, they don’t have to live within a certain spec so they can use whatever they see fit to make the best possible product.

What additives are being limited by a Euro formula? Which specification (besides BMW) limits esters?

SS is simply an RC/Dexos based additive package, nothing really better by design except that the Euro oils are using cheaper base oils.

 

[OVERKILL]

The euro formula aims to meet European car specs, while both are an excellent oil the euro specs can be quite narrow which limits the amount of additives that can be used in the formulation. This is part of the reason an ester base stock isn’t being used in the euro formulation. That coupled with other additives in the SS formulation would bring it out of tolerance. This isn’t necessarily a bad thing per se but many believe the SS formulation is better overall. It really depends on what your goals are and what your application is.

The best way to look at it in my opinion is with the euro formulation amsoil is looking to meet euro specifications. With signature series amsoil is trying to make the best possible oil, they don’t have to live within a certain spec so they can use whatever they see fit to make the best possible product.

Given that neither oil is formally approved at this juncture, that's not really relevant. The AMSOIL Euro oils are simply slotted lower in the product hierarchy than the SS oils, and this influences the calibre of components used in the product.

Also, as @scrllock notes, really the only thing that the Euro approvals limit (and that may have changed recently, again) is ester content for LL-01, since BMW imposed a total, rather than relative oxidation limit, and virgin oxidation with esters is naturally elevated. As he notes, the SS oil is based on an API/ISLAC/dexos additive package, which is why it has lower levels of phosphorous than its Euro grade mate. This is also why it's recommended for API/ISLAC applications, not Euro ones.