Tue, 05 May 1998 20:04:34 +0300 - Message No. 2839
From: Phoebus Katsanos

Subject: Re: Catalysator, performance, blah, blah, blah...


Hey guys, don't get too excited here!

Everyone is right when considering just part of the problem, but this is
a more complex matter.
The emmissions of well burned unleaded fuel are exactly the once Jorge
said, but if you could burn the fuel this well our motorcycle would be
faster, it would burn less fuel, and there would be absolutely no reason
to use a cat.
Only problem is that fuel doesn't burn exactly like this in internall
combustion engines.

Also, lead is an "antiexplosive". Gasoline tends to explode violently
under the heavy pressure and high temperature like inside the engine,
and if this happens you get a huge strain to the motor. So we need
something to keep this nasty thing from happening and this is lead.
Leadis also a lubricant for the valves and the piston, but it is a heavy
metal.
As such it is toxic, and it accumulates in the enviroment unchanged for
long time, and this is a problem in citys that have heavy traffic.

On the other hand unleaded fuel doesn't have lead, but it defenately
also needs some other "antiexplosive". This in the case of unleaded fuel
is cyclic hyfrocarbons like benzol, a proven carcinogenic. When an
engine that doesn't have a cat burns unleaded fuel, it still has no PbOx
comming out of its exhaust, but it has benzol and you can even smell the
difference! So without a cat unleaded fuel is less polutant when it
comes to heavy metals (Pb), but is at least as hazardous to your health
as leaded.

Now catalysators have noble metals on them like platinum which makes
them very expencive.
They are very sensitive to unburned fuel or leaded fuel and need a much
better tunned engine to be effective.
In fact if your engine isn't tuned right you will very soon destroy the
cat and it will soon be just like not having one at all! That is mainly
the reason why it took so long for them to become standard in cars,
since they first had to develop a way to tune the engines right, and
keep them working with the correct mixture all the time. This was
achieved with the injection systems and other electronic systems
preventing too rich mixture from getting into the engine and reaching
the cat.

Also the catalyzator in order to function has got to be on the way to of
the exhaust fumes, not only at a side, but the fumes must pass from it.
This means that in high revs when the engine needs to send the fumes
away fast the engine doesn't work this well. There are ways of working
arround this problem, but that's all they are: workarrounds!

So, IMHO the conclusion is, that with the proper technology and
evolution engineers can make cat engines more powerfull than the once
without, but this means a more complex engine (= less reliable) + more
expencive (to design + for the cat), + more weight + maybe fuel
injection + you cant rely on it being cleaner, since this depends on
heaving it serviced regularly and properly, wich studies made have shown
not to be the case.
In fact studyes in cars has shown that at about 40% of them the cat is
almost destroyed and that they produce the same ammount of pollutants as
the cars without cat + benzoil!

So I am against a cat on the Africa, as I am against fuel injection,
1000cc engine, GPS that would race the price (get your own!), or
advanced braking systems that take away my initiative as a driver.

Could it be that some of you might feel better behind the wheel of a
VMAX with catalyzator, fuel injection ABS and long suspention, with
140hp, 280kg made by Honda costing a zillion?

I don't give a shit what Honda will do for a new Africa, I have one and
hope to have it for a lot longer!

>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~<
>                   Phoebus Katsanos                  <
>          "mailto:phoebus@the.forthnet.gr" or        <
>            "mailto:pkatsan@med.auth.gr"             <
>                                                     <
>       Check out the official home page of the       <
>         Africa Twin Club of Northern Hellas         <
>                                                     <
>      http://users.med.auth.gr/~pkatsan/index.html   <
>                    mirror site:                     <
> http://www.netfiles.gr/sakis/public.html/index.html <
>                                                     <
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

dipper@normans.isd.uni-stuttgart.de