Emission test WITH and WITHOUT a catalytic converter - for your reading pleasure...

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

 

SMALL TYPO: it is ~100 mile and NOT ~100K miles... duh...

 

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.

 

Thanks for taking the trouble to do the comparison.
It's interesting to see the actual numbers.

Andy I.


: 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

 

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.

 

I put a cat on it six or eight years ago. I'll bet those bastids put a
single speed one on it instead of the 3 way...

 

Very interesting ,here we can drive forever with no tests unless we hoon
around .Many knock the inards out of the converter for more power as theres
no risk of being caught .I did this for one day while I purchased a new
converter and it seemed to run better ,more power but I replaced it the next
day with a converter .