Mobil has the ESP line for that.
Yes, which features reduced phosphorous, to protect the DPF/GPF's. That wasn't an area of concern with the full-SAPS products, because none of the approvals they targeted were spec'd by vehicles with GPF's or DPF's.
Yes, and now they have specs like ACEA C5/C6 C2/C3, MB 229.71, MB 229.51, MB 229.52, BMW LL04, BMW LL17, and so on, all of these are covered by the ESP line of products.
Yes, the OEM's all came out with their own mid/low SAPS approvals for the products with reduced phosphorous, like the M1 ESP product line. The C-series ACEA stuff was originally targeted at diesels (because of course DPF's came out before GPF's) but that was later extended to gasoline applications with the move toward the fitment of GPF's.
Therefore, there is absolutely no reason for a high performance Full SAPS oil to even try to offer DPF/GPF protection, and it might actually not, even in API SP guise.
Well no, why would they? None of the approvals targeted by a full-SAPS oil has a GPF/DPF. Those all specifically call for either an ACEA C-series approval or OE approval. The only exception is GM with dexos, which calls for an ESP oil in a car (Corvette) that doesn't have a GPF, but that's more consistent with the typical API-geared approach on this side of the pond where everybody tanked phosphorous in the RC grades starting with SM.
Also, Magnesium Sulfonate is not really desirable in high performance motor oils. I mean, if it's there, it's fine, but it will deplete rather quickly under high heat and stress.
I think that this is about additive package convergence (Infineum) and competition. Shell had their Helix API SN Plus / SP clones on the market since late 2019 / early 2020 with a Calcium/Magnesium additive package that looks nearly identical to Mobil's FS add pack, except for detergents. I think Mobil is fixing that now and getting in line with Shell's product line. So, I don't think this is about exhaust system protection, when they already have a product line that addresses that specifically. And it's a very good product line.
You've lost me. You don't think what is/was about exhaust system protection? My point was simply that the full-SAPS oils were not targeted toward applications that featured DPF's/GPF's. Most of these oils long pre-date the fitment of those devices to vehicles and when DPF's first started to appear on European diesels, the low and mid-SAPS oils (ESP...etc) and the C-series ACEA approvals appeared as part of that transition. Later on, when GPF's began to be fitted, that scope was expanded (as were the OE approvals, many of which you listed) to cover those applications as well. There was then a clear delineation between the full-SAPS oils, not deemed suitable, nor spec'd, for DPF/GPF applications, and the low/mid-SAPS oils which were specifically geared toward them.
Where things are muddied a bit is where OEM's back-spec'd some applications to low/mid-SAPS approvals, like BMW, so you had an application that originally called for LL-01 for example, now spec'ing LL-14. This wasn't about DPF/GPF protection, since the vehicle wasn't fitted with one, it was more about a broader transition away from full-SAPS oils in their engine fleet, likely to make things less complicated for dealers.
Visc Index of 165 regardless... Seems a very complicated, mix/mash recipe for results.
