OVERKILL
$100 Site Donor 2021
You realize that we aren't talking about eliminating these compounds with lower SAPS oils right, they are still present, just at reduced concentrations. So, if an engine is drinking considerable oil; enough to cause catalyst damage, it's going to happen with both products, the idea is that it takes longer to happen with the low SAPS product so that it's out of warranty, if one wants to be cynical.
The push for low SAPS oils started in Europe with the introduction of DPF's on diesels. Those oils were dual rated and there was a lot of crossover, which made the same change with the petrol engines easier when GPF's were introduced. It's not like full-SAPS oils were only recommended for engines from 1964 without catalysts, all cars that they were recommended for were catalyst equipped. The reason you don't hear about bimmers and benz's puking cats constantly is because in reality, it really isn't much of an issue with the quality of oil that's ensured through the approvals.
On this side of the pond, Phosphorous was reduced with the introduction of API SM, but the API limits on volatility and other parameters are a bit, well, lax. With the push to thinner oils and increase in consumption, protecting the catalysts under a high consumption scenario while under warranty was important. On the other hand, with the xW-40 oils, that limit was never applied, which is why they could be SM, SN, SP and still be full-SAPS.
