re: FW: Re:'78 Spider FAILS the NC Emissions test!

[Jay Negrin <jmnegrin@domain.elided>]

Hi group,

I believe that the extra air supplied by the "smog" pump is to aid the
catalyst in oxidizing, not so much CO (carbon MONoxide) to CO2 (carbon
DIoxide) , but unburned hydrocarbons (HCs) into more CO2 as well as
water (H20).  This works OK in a simple, mid-70's, single-stage
catalyst.  My 76 Alfetta is another good example.  The car runs OK
without the air pump (I had to for a while), but would never pass smog
emissions testing (never mind the visual).

Also, I think there is a possibility that NOx could go up, as you are
adding more air, which is 80% nitrogen.  The heat of combustion makes
some oxides of nitrogen (NOx), and I wouldn't be surprised if the heat
in the cat would be enough to stir up some more.

To get the NOx to go down, other than radical motor surgery, you would
need a 3-way catalyst, and the motor controls to fine tune the fuel
delivery.  As good as SPICA may be, I don't think it can deal with the
rigors of an O2 sensor and other related hardware (and software).

And *that* is my tuppence on the subject.

Jay Negrin
ARO So Cal (where 'smog' is a verb, as in, "I am going to have to get my
car smogged before I register it this June."


> Subject:      Re:'78 Spider FAILS the NC Emissions test!
>
> Jerry,
> You must reinstall the air pump to lower the CO emissions.  The air
> pump is installed to ensure adequate O2 (read air) is available for
> combination with CO inside the catalytic converter.  Once you install
> an air pump you should see a drastic reduction in CO and Nx gasses.
>
> Good Luck
>
> Anthony Savage
> San Diego

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