It's possible the term refers to:
* A Cadillac-branded catalytic converter: Cadillac, like other car manufacturers, uses catalytic converters in their vehicles to reduce harmful emissions. Someone might refer to one from a Cadillac as a "Cadillac converter." However, this is not a standard technical term.
* A high-quality or expensive catalytic converter: Perhaps someone is using "Cadillac converter" to imply a superior or more expensive aftermarket catalytic converter, similar to how "Cadillac" is used to denote luxury and high quality in general conversation.
* A mishearing or misspelling: It's possible the term is a mishearing or misspelling of another automotive part or technology.
Without more context, it's difficult to say definitively what "Cadillac converter" means. If you encountered this term in a specific context, providing that context would help clarify its meaning.
