>        Once I've got the obvious stuff done on my bus, I'm going
>to look into a catalyst retrofit. Of course, the aircooled engine
>runs richer than watercooled, so the catalyst will have to
>burn-off that fuel, and the CO produced by the rich mixture too.
>Maybe it won't be practical, maybe I'll lose horsepower, but
>I read once of someone trying to commit suicide with a catalyst
>equipped car, and after 2 hours they gave up and decided to live!
>I've got the typical header system now- that might give me short enough
>pipes on cylenders 2 and 4 to get the catalyst hot enough to work.

Good luck, but I'd be dubious about the life span of a catalyst on an air
cooled engine without fuel injection.  Also, if the engine isn't running
very close to stoichiometric the catalyst will do a poor job on either
VOC's/CO or on NOx, or both, so you're going to run into a tradeoff between
catalyst efficiency and reduced engine life by leaning out the carbs.

I recently saw a copy of a 94 Mexican sales brochure.  The beetle has
closed loop (O2 sensor) fuel injection and a catalyst, however, a  contact
at Environment Canada claims that the cold start emissions from the air
cooled motor are all still over the place.