Catalytic converters: 2-way or 3-way ??

[AlaskaToy]

What is the difference? What should I replace mine with on my 93 toyota 3vz-e V-6? I don't know if the stocker is a 2 or 3-way unit. Should I go with the stock 2" inlet or go to 2.25 or 2.5"? I am re-doing everything from the exhaust manifolds back. Thanks...

[fzj40]

3 way converters have an inlet from the air pump.   Yours does not, it is a two way.  Use 2.25 or 2.5 all the way back, depending on your other mods.  If you are relatively stock I would stay with 2.25. 

[yota-tota]

well i'd just run 2.25 staight back from the manifold with no cat that's what i did and it worked out fine on my 22-re, not sure if it makes a difference on 3vz-e.