The difference is that the dual exhaust system has two exhaust systems on one vehicle. Meaning, when modifying your exhaust, never start from the front of your turbocharged vehicle with a downpipe or with 82-92 camaro headers on your naturally-aspirated platform, you will create a bottleneck in the flow. By starting with a cat-back first, your exhaust gases will flow more freely if the rest of your system is stock.
Engines fitted with regulated 3-way catalytic converters are equipped with a computerized closed-loop feedback fuel injection system using one or more oxygen sensors (also known as Lambda Sonds or sensors). Other variants combined three-way converters with carburetors equipped with feedback mixture control were used. An unregulated three-way converter features the same chemical processes but without the oxygen sensor, which meant higher NOx emissions, particularly under partial loads. These were low-cost solutions, typically used for retrofitting to older cars or for smaller, cheaper cars. Axle-back exhaust systems replace only your vehicle’s rear exhaust section, usually consisting of items behind the rear axles, like rear exhaust pipes, muffler, and exhaust tips. A