Quick question while were waiting to see what's up with Hydra747's truck.
Can I delete the second catalytic converter or place a high flow glasspack in there without screwing anything up.
If I punch out the internals on the first catalytic converter will this screw anything up?
In short, no, and yes.
Both cats are needed for the ECU to operate correctly. Doing either of what you have suggested will result in the ECU reverting to "limp home" mode and WILL NOT improve anything (poor fuel consumption, poor performance). Cats these days have almost no effect on the exhaust gas flow, so there is absolutely nothing to be gained from trying to eliminate them.
Worst case scenario is that you will be up for new O2 sensors as well due to contamination.
Gary, not quite correct, at least for 1998 and newer Sportages in North America.
The cat that is bolted to the exhaust manifold is indeed monitored by the ECU from the rear O2 sensor. You cannot remove or gut this converter. It is required for emissions as well as keeping the ECU happy and CEL free.
The second cat under the driver on left hand drive is not monitored. It can be removed or gutted with no driveability effects other than slightly higher emissions. If your state/province conducts tailpipe emissions tests on an annual inspection you might fail. But other than that the ECU will never know it's been removed or gutted.
This does NOT apply to 1997 and older Sportages in North America. They have one cat under the driver and it is monitored by the ECU.
