Slightly tangential, for the ZDPP issue:
There have been incentives/mandates to improve fuel economy over the past decade.
Fuel economy can be increased by reducing the ring friction against cylinder walls
Since this approach towards fuel economy results in more oil blow-by past the rings, more oil vapor will be hitting the cat
And it turns out that certain components commonly found in oils up to that time will ruin/"poison" a cat
So a new spec of oil was made without these components for new cars so the expensive cat is not destroyed in short order.
The old spec oil has been made less widely available. ZDPP additives/similar are available to adjust the difference between the old oil spec and what can be found easily today.
There have been incentives/mandates to improve fuel economy over the past decade.
Fuel economy can be increased by reducing the ring friction against cylinder walls
Since this approach towards fuel economy results in more oil blow-by past the rings, more oil vapor will be hitting the cat
And it turns out that certain components commonly found in oils up to that time will ruin/"poison" a cat
So a new spec of oil was made without these components for new cars so the expensive cat is not destroyed in short order.
The old spec oil has been made less widely available. ZDPP additives/similar are available to adjust the difference between the old oil spec and what can be found easily today.
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