Exhaust diameter question, SMOG related.

95DC2GSR

New Member
This may come off as unintelligent but I'd still like to ask. I know SMOG is based off of AFRs, and that changing to a larger diameter piping isn't going to affect the AFRs much. Knowing that, I'd still like to know if going larger will affect the amount of HC, CO, and NOX being recorded?

Say you have the same header, just a 2" collector and the same size cat with 2" inlet and outlet and 2" piping all the way back vs. same header with 2.5" collector, 2.5" inlet and outlet, and 2.5" piping all the way back. Will the 2.5" exhaust register more HC, CO, and NOX because it's flowing more?

Thanks in advance.
 
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