Topic: This is exhausting!

[Angry Chicken]

For simplicity, one “run” from the engine includes all the stuff behind the exhaust manifold on its way to the muffler: catalytic converter(s), resonator(s), and such.

[tpl]

for two runs you would need 4 oxygen sensors and 2 catalytic converters.  expensive.   As well as software changes  to handle the two exhausts separately.

[jamie1]

for two runs you would need 4 oxygen sensors and 2 catalytic converters.  expensive.   As well as software changes  to handle the two exhausts separately.

"V" and boxer engines already have that stuff.

[random006]

for two runs you would need 4 oxygen sensors and 2 catalytic converters.  expensive.   As well as software changes  to handle the two exhausts separately.

The cost for each of the four methods is not at issue here.  Only the definition.

[Gurgie]

Option 3 is in the lead