<VV> Catalytic Converter for Corvair

[NicolCS at aol.com]

Bill wrote:

Something occurred to me...couldn't I  install leaner
jets in the carbs?

For most city driving (90% of my driving is city under
30 mph) there is no bad smell whatsoever; when I get
the car up to 50 mph and over, I can smell the rotten
eggs (very slight).

btw the car still runs much better with the cat
installed.  Gas mileage is the same as before.

Thanks guys for your advice...Bill Hershkowitz
 
Craig replies:
The basic answer is "yes" a leaner main jet will lean-out the cruise, 
especially when we remember that lots of folks throw in larger jets (usually 53s) as 
a matter of course.  I'm a big fan of data and knowledge though so if it were 
me, I would install an oxygen sensor based air/fuel ratio meter and find out 
what's really happening.  I'd also suggest reading Bob Helt's book on Corvair 
Rochester carburetors so you can learn the effects of emulsion tubes and 
correction orifices to really do the job right.  Here's what happens if you go too 
lean: (which is NOT "leaner", I mean TOO lean): combustion chamber temperatures 
go through the roof resulting in detonation, burned valves (or pistons), and 
prodigious Nox production.  There are two types of oxygen sensors: Wide band, 
which are relatively costly ($300 ish) and narrow band (which are more like 
$120 ish). Narrow band sensors will do the job (that's what I use) but aren't 
nearly as accurate and require more thoughtful interpretation (guessing)
Craig Nicol




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