Just browsing Real OEM and the Sewell parts sites and noticed something odd?

The part diagrams show the following:



US Spec

1 = "Replacement catalyst with center muffler" (18308616386)

Euro Spec

1 = "Front Muffler" (18308616385)

then…..



shows the same for both cars with 1 = "Exchange of engine-side catalyst"

Surely the US spec cars don't come with 2 x cats??

 

Gimme a couple days and I can tell you for sure. But I agree, it does seem like overkill to have 2 cats on such a small engine.

 

US and Euro emissions standards are different which likely results in different design decisions. Cars these days use three-way catalysts and it may be more efficient for US cars, to separate one of the functions in a separate cat rather than building all three reductions into one, especially given that each may have optimal temperature environments for best efficiency. It's probably not a matter of one being "better" or "overkill", just a different approach to meeting spec.

- Mark

 

Heck....cats are pretty new for Europe.... About 10 years or so if I recall right......and as stated above...different rules.....different specs...not real surprising...
In the us cats have a very long emissions warrenty....
So to lengthen the life of the main cat, there is usually a smaller "pre-cat" very close to the motor...heats up very fast on startup.....
Even the gen1 cars have this setup....