Postby smj999smj » Thu May 03, 2018 11:35 am
Federal emission vehicles came with two converters that bolt directly to the end of the cast-iron exhaust manifold. California emission vehicles came with four converters: two similar to the Federal emission vehicles and then another two that are built into the front pipe assemblies.
If you have the CA emissions style and wanted to replace the rear converters, you could just swap them with a front pipe for a Federal emissions-type Pathfinder. Walker #'s 53482 and 53483 would work for that. It wouldn't create any CEL issues because the rear converters are not monitored by the ECM. While it would likely pass SC emissions, technically, it is Federally illegal to remove or tamper with any factory-installed emissions device on a motor vehicle. Whether they would catch you and prosecute you are highly unlikely, though, as they probably have bigger fish to fry!
To replace the upstream converters on a CA emissions vehicle...or replace the two converters on a Federal emission vehicle, is a bit more difficult due to the design of the mounting between the exhaust manifold and the converter. The only way I could see doing it would be to replace the manifold and converter with headers, which would require using CEL eliminators to keep the ECM from triggers catalyst efficiency codes and turning on the CEL light.