Originally Posted By: vinu_neuro
A5/B5 and A3/B4 call for lower wear than A1/B1, and they all destroy your standard PYB which just meets SN and GF-5. I'm not sure where the extended drain idea came from. Specs show A1/B1, A3/B3, A3/B4, A5/B5 all require >= TBN of 8 and there's nothing about retention.
As far as wear goes, in a naturally aspirated, non-direct injection, non-Euro engine, most people are likely fine on dino. But when a 1990 Honda specs 7.5k intervals on conventional, you might as well do 10k on A1/B1 or A5/B5 and take the lower wear too.
We don't know that any of these specs "destroy" PYB, since PYB was not tested to them and doesn't claim to be.
We do know that PYB performs very well on the drain intervals most of us use.
Your Honda was very optimistically claimed to allow 7.5K changes on any API SJ/SL.
We've had six Hondas, mostly driven under pretty easy conditions, where 7.5K would be accumulated in as little as four months, and I've never run one much beyond 6K on the Grp III oils I normally use.
If I were to contemplate 10K, it would have to be backed up with UOAs at shorter intervals, regardless of what specs the oil might claim to meet.
I do have a 6K OCI UOA of PP 10W-30 coming for our older Accord, so it will be interesting to see what it shows.
Empirical results trump standards based upon test protocols every time.