On Thu, 22 Dec 2005 15:10:24 +0000, Chris Bacon wrote
(in message ):

[ Catalytic converters have little place in motoring in the UK. ]

Yes they do - as anyone who walks close to town traffic will know. You
can instantly tell an older non cat equipped car by the smell. And
it's not pleasant.

This is rubbish. Most cars are used for short journeys, during
which their catalytic converters do not work properly.

It would have to be a *very* short journey indeed. Most these days light
up very quickly.

How short a journey?

Probably improved in recent years, but I think you'll find that a significant
propertion of commute journeys do not heat the cat up to working temp at all
(especially in town/city driving when low average power is used). This is in
fact a significant factor in the fact that many cats are totally dead by the
first MOT test at 3 years old - 'crap' builds up on the matrix during these
short journeys, when the cat does 'light up' on the occasional hard
drive/longer journey then the crap burns off and causes the matrix to
overheat and disintegrate.

I didn't mention lead, just that finely divided platinum is being
emitted all over the place. Incidentally, lead-free fuel is quite
capable of being used in non-cat. cars, so I'm not sure what your
comment pertains to.

Not to mention that to make a cat work properly, excess fuel is burned to
create the right conditions in the exhaust. Yes, cats make cars burn more
fuel. Oh yes, and if cats hadn't been mandated then by now we'd probably have
some incredibly lean-burn engines using much less fuel than current engines -
but such work was abandoned as lean-burn doesn't work with cats.

What does a catalytic converter spit out then it's not yet
functioning well?

See above. But the same as a non cat engine.

With any reduction in fuel economy?

See above, if the cat wasn't fitted then the car might be burning less fuel
to start with !