Since he'* asking for a bushing and you are the only one that knows what he'* talking about.. Can you please fill us in

Thanks

PVC bushing for example. He means stainless, but won't find them.

2.25" pipe slips INSIDE at the top section. 2.5" slips OVER the larger bottom section. Provides a 'step' transistion for exhaust flow.

See the problem?

That'* like hitting a brick wall. Yes.

Thanks for the info..

if he is going from 2.25 to 2.5 it is backward of how you are thinking.. it will not be hitting a brick wall, it will be hitting a huge clearing

Which is still not good for exhaust flow. You want a smooth transition.