s6q@mhuxh.UUCP (STANIK) (01/27/86)
[...]
A couple of weeks ago I posted a query about replacing a partially
clogged catalytic converter with a piece of pipe. In case someone
else has thought about it; here are the ideas
that were relayed to me. Without a doubt I couldn't have been told
everything and something here maybe in error, but I am no expert.
[Here goes]
Basically a catalytic converter is an incinerator for anything that
tries to go through it, as long as its not overloaded with something
(lead ash, lots of motor oil, PCB's .etc). Thats when it starts to
clog. If one simply replaces the converter with a piece of
of pipe then the change in backpresure changes the vacuum advance
on the distributor so retuning the engine is necessary. However,
there is something called a "test pipe" which is designed to provide
backpresure, this eliminates some of the difficulties. Getting one
maybe a problem though.
Another route is replacing the catalyst. Some
cars use Platinum based pellets which can be removed. The new ones
can be added with common household items without removing the old
converter from the car, which is desirable. Like the converter though,
the pellets are expensive and there is a potential safety hazard.
Unless one knows why it got clogged in the first place, replacing
catalyst could become an expensive habit.
Without a converter a car may run on leaded gas but the lead will
foul the spark plugs and corrupt the oxygen sensor so more frequent
tune ups maybe necessary.
There were two items that I found interesting in spite of all
that was told:
o Someone said they replaced the converter on a 1981
Chevrolet Impala with a "regular" piece of pipe and
it runs on regular gas. No other adjustments were done
and the car still runs fine.
o It was mentioned that Subaru's are sold in California
without a catalytic converter; apparently it is the
only one that was could pass the test for exemption.
Appears to be true; The mileage estimates listed for
a 1985 Subaru were higher in California than in
the 49 states, there could be another explanation for
this though.
I would like to thank those who replied, most of them
were informative and friendly. The only comment I would like to make
is in reguards to the letters stressing only the legalities of
removing the converter. It was interesting that most of these type
of letters the author backed up his/her statements with inconsistent
or irrelevant information. For example:
"Since what you want to do is illegal; your car will
probably shake apart."
This makes me wonder if there was a lot of thought between the
above two statements or none at all.:-)
Thanks again,
-Tom