AIR pumps, valves, and new cats

[David & Cheryl Haggard]

   My apologies for the duplicate posting. But there are multiple threads
talking about AIR control, so I thought I'd post this as a new thread.
   Two somebodies on two separate threads said...

> With the 7747, emissions may be good enough that
> additional air isn't required to light the
> convertor.  The xfire runs extremely rich at idle and
> when cold with the OE ecm, the 7747 won't be this way.
   .........and...........
> The A.I.R. valves are what concern me the most. I'd
> like to get those setup properly.

   About catalytic converters, and the need for AIR pumps and valves, here's
something I was reading just yesterday. It's on the Random Technology
website (RT makes high-flow cats) at
http://www.randomtechnology.com/technical.html. Reprinted from "Turbo & High
Tech" magazine.

<quote>
Although "three-way plus oxidation" type converters were prevalent during
the 80s, that's no longer the case. With improvements in washcoat
technology, and improved control of air/fuel ratios, the need for additional
oxygen has been eliminated. Some vehicle manufacturers have continued to use
oxidation converters on some models, but typically that has been done to use
up inventory. As an example, the Corvette and Camaro Z/28 were equipped with
oxidation converters through 1991 and 1992 respectively. But when the LT1
engine replaced the L98 (1992 in Corvette, 1993 in Camaro) three-way
converters with no air tubes were incorporated.
<end quote>

   With good fuel mixture control, the AIR pump and its valves are not
needed with a new-style three-way converter.
   The only problem that could arise is if your area requires a visual
inspection for emissions, and you can't convince the authorities that, with
the new converter, you don't need the AIR pump anymore.
   Seems to me since we're all reprogramming, and most of us are using
7747's to do it, the required mixture control should be there. If we do it
right.
   You can legally replace your cat with a new three-way, high-flow type
(like from Random Technology) if the car has over 50,000 miles on the clock,
and it's over 5 years old. This can allow you to eliminate the AIR system
altogether. That is, if you can get it past the authorities.

Dave Haggard

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