Ok well I went and ordered a new cat. the walker universal 2 1/2 in and out and 13 1/4 and it is a 3 way part # 15033. All I ask of it is that it works for 1 day every 2 years. LOL
Dave
A two way cat is a oxidation cat only. It combines O2 with HC and CO to make CO2 (carbon dioxide) and H2O (water), the byproducts of perfect combustion. A three-way-cat (TWC) has an additional bed that removes oxygen direvitives (sp) from NOx to created N2.
Salvage6:
the TWC used to need air to cool the mixture, but with the introduction of computer controls and O2 sensors, that became obsolete. Now most air injection systems are used to get the cat to light off when the engine is cold. The O2 sensor tries to maintain 14.7:1 a/f ratio. The best it can do is 14.5:1(rich) to 14.9:1 (lean). When it's rich in the cat, the cat uses this oportunity to reduce NOx (by putting combustion out), extra O2 is stored and when the mixture in the cat is lean, the store O2 and extra O2 from lean mixture is released to convert Hc and CO to CO2 and H2O. That's the short explanation, imagine a long version coming from a motor mouth like me .