At 04:06 PM 3/18/2012, Alistair Bell wrote:
>I was just curious about how an engine that came with a cat would
>run sans cat. No moral or ethical opinions on the subject was included.

My California-standard '84 ran the same burning leaded gas in
Scotland with a straight pipe and no O2 sensor (as delivered in
Germany) as it did burning unleaded with VW-supplied sensor and CAT
and restricted filler opening when it came over to the US.  Within my
ability to tell, anyway.  I can't really speak to economy.  It was a
long time ago and I wasn't paying attention to mileage when I was in
Scotland anyway.  But my impression is that it did better in Scotland
than here.

Yours,
David