Which cat do I kill?

[Harlen]

Like many others, my '98 preface SR has a cat after the manifold and a conventional one underneath the car. Is there a cat which you can kill, but still pass emissions test on? Only reason I'm asking is that I've seen a few people remove a single cat, which there must be a good reason for

 

[pollyp]

the primary cat under the manifold does most of the work. the secondary one doesn't get hot enough to work properly

 

[frank]

and the coilpack ones have a single precat that is 2 x longer and has very fine pores, which leaves options for getting a better flow, or else improving emissions

 

[Harlen]

Thanks for the answers chaps, exactly what I needed to know!