In article ,
Nick Maclaren wrote:
Worse, they work only after
the engine has warmed up (about 5 miles) and the average trip in the
UK is about 3 miles.

This may have been true when they were first introduced, but modern types
work much more quickly. FWIW, a cat doesn't rely on the engine
temperature, but that of the exhaust gasses which are largely independent
of this.

--
*Ham and Eggs: Just a day's work for a chicken, but a lifetime commitment

Dave Plowman London SW 12
RIP Acorn