Ben/Pam Zwissler wrote:
> The fuel systems on most pre 1974 LBCs have nowhere near the mixture
> control required to support a catalyst. In general, you will require an
> oxygen sensor for feedback to get that good of mixture control.
Well, I think this is kind of half of a statement. The oxygen
sensor is a feedback element indeed, but requires an EFI system
or a system where a computer can interpret the sensors to adjust
the mixture.
Nothing you said was wrong, but I just felt too much onus was
being placed on the oxygen sensor, when it is only a data gathering
device for what really solves the problem, computer correction
of mixture.
One option would be to install a sensor to monitor mixture,
and then essentially "keep the car in very good tune". Catalytic
equipped MGBs were spec'ed to run rich, about 3% CO, and would
behave as long as tuned to these specs. Non-adjustable
carbeurators helped "enforce" this to some extent.
A common oxygen sensor is not a terribly usable exhaust gas
analyser, although it can provide some data. However, if, as
was stated, installing a catalytic converter will save $500
in licensing costs, that's a fair bit of latitude. I have
seen cheapie exhaust gas analysers in the range of $200US
and that run on 12V.
Perhaps you could employ one live on the car to keep
mixture inline, if that is important to you. It would
allow you to view the mixture during various engine
states.
Although, I have to question the severity of the problems
with minor tuning issues on catalytic cars. I am aware that
grossly wrong mixtures will cause cherry-red catalysts, but
I can think of a lot of cars out there on the road that
just aren't running even near tune, even EFI systems because
of failed O2 sensors or clogged injectors. I have not
seen the kind of "disasterous results" from these situations
that these statements would indicate.
--
.---------------------------------------Ottawa-Canada-GOSENSGO-----.
/ Trevor Boicey 1992 Celica GT 1975 MG Midget /
`----- tboicey@brit.ca ------------------------------------------'
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