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 5W-30 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 SS AZF