Originally Posted By: wemay
This^
Good information share, SR5.
Thanks Mate,
Looking over the 2010 ACEA Sequences, the Noack volatility limit for A5/B5 is 13% but for A1/B1 it's 15%.
So compared to A1/B1, a A5/B5 oil is required to have a higher min HTHS, a lower max Noack, lower cam wear results and cleaner piston rings.
Note, I'm talking about the standard here, not individual oils. Many oils like M1 5W30 (A1/B1) easily meet the A5/B5 standard for some factors such as Noack and HTHS. Still other oils like PP 5W30 are rated A5/B5, which reflects well upon them.
If you want to step it up another notch, consider a Ford WSS-M2C913-D oil. It starts as a full synthetic 5W30 A5/B5 oil, and then Ford adds Increased TBN requirement (from ACEA level of 8 to a Ford requirement of 10) and an extra cam chair wear test (which often translates to more ZDDP at about the 1000 ppm level), plus extra oxidation tests and seal compatibility tests.
Most of the Ford 913-D oils I have seen are "only" SL rated due to their elevated Zinc & Phos levels, but those A5/B5 requirements that are pushed even higher by Ford, make for a great oil.
The 913-D 5W30 is the required oil for the Ford Mustang in Australia.