clay wrote:
> James Sweet wrote:
>> Radioguy wrote:
>>> On Mar 8, 3:14 pm, Someone <some...@somewhere.com> wrote:
>>>> The 90 240 I bought had a defective CAT and failed the emission test.
>>>> So I told the garage to empty the CAT. I wanted to see what kind of
>>>> number you get without a CAT. I then had a brand new CAT installed,
>>>> drove ~ 100K miles and then took the test again. Below are the
>>>> numbers I got:
>>>>
>>>> With an empty CAT:
>>>>
>>>> At 40km/h (24mph) Curb idle test
>>>>
>>>> HC ppm 134 107
>>>> CO % 0.86 0.85
>>>> NO ppm 2753 N/A
>>>>
>>>> With a brand new CAT:
>>>>
>>>> HC ppm 46 24
>>>> CO% 0.09 0.00
>>>> NO ppm 94 N/A
>>>
>>> And your point is that the car pollutes less with a catalytic
>>> converter installed than without one? Hope you didn't pay extra for
>>> this information.
>>
>>
>> I thought the data was interesting. Of course it pollutes less, but
>> it's interesting to see some quantities. The difference on that car is
>> much smaller than I've seen on some cars, the 240 would still pass the
>> emissions inspection here without a cat, many cars wouldn't. With one
>> it's very clean.
>
> I get where a cat helps unburnt hydrocarbons.
> Interesting it has such affect on carbon monoxide and nitrogen oxides.
> My old 240 is always right on the edge for NO (better though, with the
> knock generator vacuum line plugged.)
> May be time for a new cat.
CO is just partially burned hydrocarbons, so it's no surprise there. 3
way converters are specifically designed to reduce nitrogen oxides as well.
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