Has anyone done this? Will I throw a check engine code without it? I have the feeling that the van is struggling against back pressure.
Also how will it change the sound?

Thanks

 

There are some models that use O2 sensors ahead and behind the converter to check its performance. So removing the converter will cause an error code.

If your engine is indeed struggling against back pressure of the cat con, then it's probably plugged up and needs to be replaced. More to the point, something in the way the engine was operating caused the congestion, and it should be fixed.

Back in the 70's ARCO was using a manganese based octane booster (Methylcyclopentadienyl manganese tricarbonyl) to replace lead tetra-ethyl, and its residues clogged a lot of catalytic converters. Today, MMT is still used by a lot of gas producers, but in smaller concentrations. But if you use it enough, it will clog your converter, as well as leave residues in every other part of the combustion stream.