60
STAG OWNERS CLUB TECHNICAL REPRINTS
There are two types of converter. The basic type is just
The cost penalty on new cars therefore also becomes
like a silencer box, and could in theory be added to
significant. Add to this the regular compulsory
any engine. The more complex type has electronic
testing which will need to be applied, routine
probes which are connected to engine management
replacement, etc, and the cost to the motorist is very
systems so they not only more closely control what
significant indeed. Another very important cost is
comes out of the tailpipe, but they also control very
that the converter significantly reduces engine
closely what goes into the catalytic converter.
efficiency, meaning great loss of power and heavier
fuel consumption for given acceleration Speed .
DO THEY REALLY WORK?
Firstly, they will not cause the exhaust to be entirely
WHAT ARE THE ALTERNATIVES?
clean. They only work on a range of pollutants, and
Vehicle manufacturers have been working on lean-burn
turn them into other pollutants which in some cases
engines for sometime. Their features are that they
are thought to be less dangerous.
use the energy in petrol much more efficiently and
For the chemical buffs, carbon monoxide is reduced by
have very clean exhausts. Therefore they use much
50-60 per cent, unburned hydrocarbons and nitrogen
less of our valuable fuel important also in conserving
oxides 40-70 per cent. We can do without these
our finite resources, preserving performance, and
substances, for there does seem to be fairly strong
costing us less in money per mile travelled.
circumstantial evidence these lead to `acid rain'
I turn to the politicians again. Who else would make
note this is not proof. In any event, car exhaust
such big issues out of unproven theories. Why would
pollution of these substances is minuscule in
they not wait for the much more sensible lean-burn
comparison to industrial and domestic burning
generation of engines? Maybe the parties in power are
processes. The end product of this chemical reaction
paranoid about the power of the `greens' in Europe?
is carbon dioxide, which any `green' will tell you leads
WHAT CAN I DO?
to the much-publicised and emotive greenhouse
Any engine can be made to run fairly cleanly by accurate
effect. Not quite sure I believe that one, but who
tuning. Are you doing your bit to reduce atmospheric
knows, show me the proof! Whatever, one pollutant
pollution Stag or other car? Are you using unleaded
becomes another!
fuel in engines capable of standing it with modifica-
Finally, remember that California introduced the very
tion if necessary? Have you spoken to your MP?
strictest exhaust emission regulations in the world in
Issue 111 (August 1989), pages 23,24
1973. Today they still suffer from severe acid smog.
Catalytic Converters. Klaus Schluter (15810),
Does this answer your question?
Diplom-Ingenieur, wrote from Munich in
HOW LONG DO CONVERTERS LAST?
response to an appeal for information on
Not all that long, really. A perfect catalyst would never
catalytic converters on Stags:
wear out, but these are not perfect. The life of the
CATALYST AND CARBURETTOR does that fit
converter is related to the amount of products it has
together? Yes, it does! The actual list of the German
to deal with. Therefore an incorrectly tuned engine
Automobile Club ADAC shows a dozen suppliers
running at full bore will burn out the catalysts very
offering controlled catalysts for approximately 300
quickly. Conversely, a finely tuned engine which
different German car models built from 1970 to 1991,
measures and adjusts its own exhaust products
showing the VW Beetle (1970) as well as a BMW
continually will last a long time.
3.0 CS, a Mercedes 350 SI (1971) or a Porsche 911
An oily engine will cause a converter to `die' very quickly
(1973). Some thousands of classic cars are
indeed.
meanwhile running with a controlled catalyst and
WILL THEY FIT STAGS?
many of them are fitted with carburettors. Prices are
No. The engine just cannot deliver a clean enough
from around DM3,000 (£1,200) to DM7,000 (£2,800).
exhaust to allow a converter to last any period of
The basis for the approval of a catalyst-system are the
time. As stated last month, a sophisticated electroni-
EC Regulations for new vehicles which are valid in all
cally controlled fuel injection and ignition system
EC member countries. Over the years, these regula-
could deliver the goods, but the development and
tions reduced step by step the limit values for the
production costs would run into millions of pounds.
exhaust gas of new vehicles. Due to the very
complicated test procedure, and the low limit values,
AND HOW MUCH MIGHT THEY COST?
the costs of development for an add-on controlled
At the minimum about £200.00 to cars which are other-
catalyst system add up to DM35,000 (approx
wise suitable. The sophisticated ones can cost
£15,000). I assume this will be the same in England.
£800.00 and need changing around every 25-50,000
Based on the EC Regulation 91/441 /EWG, we have two
miles. Usually they also need a change to stainless
Swiss Stags fitted with a controlled catalyst system,
steel exhausts to combat the severe exhaust
the only ones in Europe I've ever heard of.
corrosion these engines are capable of producing.
Recently, the German Government has lowered the
It has been suggested that catalytic exhaust systems will
limit values, as well as the test procedure, dramati-
cost about 64 times that of the more ordinary
equivalent systems.
cally for add-on catalysts they claim to get rid of the