Dear friends on the list,
a while ago, there was a discussion about fitting catalytic converters
to our triumphs and how that could be done. The reason for the
discussion was, if I remember correct, the question of a list member
from Germany, because of the very high taxes on cars without 'cats'.
However, the tax problem is solved since a few weeks, if the car is
older than 30 years.
Today, I received a mail from my local lbc guy, who produces catalytic
converters for the TR 6 and 250. I found his description very
informative, so here it is.
I have no financial interest....
Greetings,
Heinz
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Computer controlled catalytic converters for english classic cars.
HOW DOES IT WORK ?
The catalytic converter can only work properly provided the petrol-air
mixture is near perfect. This so-called lambda =1 value cannot be
reached nor maintained with sufficient accuracy with our good old
carburetors. That's why the mixture has to be altered as follows :
First the carbs are set on the rich side. Before this rich mixture
reaches the combustion chamber it is made lean again to the point were
it corresponds with the above mentioned value lambda = 1. This is done
with a very accurate and quickly operating air-valve sitting behind the
carburetors.
This electronically controlled valve gets it's main information - the
lambda value - from the lambda-sensor in the exhaust. Furthermore,
account is taken of some other engine characteristics. The most
difficult part, however, is to take account of the complex situation
arising from continuously changing engine- and environmental
conditions, and the time-lack between the measurement and the actual
setting of the mixture. The air-valve should work in such a way that
not only exhaust-data, but also running characteristics are near
perfect. This set-up is very complicated and must be calculated within
such a short lapse of time that we had to install a computer that,
itself, had to be programmed in complicated trials for each individual
model.
THE CONVERSION
CONDITIONS
In order to guarantee the proper set-up of the system, i.e. exhaust
fumes that comply with the regulations, the engine has to be in
pristine condition. Engine, ignition distributor and carbs have to be
checked and repaired where necessary. An oil-burning engine will
eventually ruin the catalytic converter! We do recommend electronic
ignition and multi-point plugs. The cylinder-head does not necessarily
have to be fitted with hardened valve-seats. A suitable lead substitute
will do the job!
GARAGES
It really makes sense to have the conversion done by a TRIUMPH, MG or
AUSTIN-HEALY specialist. Only when the job is done properly will your
catalytic converter work the way it was intended. If you really want to
do the job yourself, don't forget to have it checked by a HJS-approved
dealer who will also be able to activate the electronics!
FITTING
The conversion-kit is fairly easy to install within a reasonable time.
The originality of the car is hardly affected. Cost will be very
reasonable. Please ask your specialist.
German clients will need to have their cars TuV-checked! Furthermore
the car's papers will have to be altered. Only then will it be possible
to get a tax discount for "clean" cars.
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