[mwebb]

Originally Posted by moonmonkey

my echo has a cat,,,then a resonator,,,,,then a muffler, if i were to replace the resonator with a pipe ,,, i know the noise would go up , but would there be any mpg increase? i dont want to sound like a ricer, but for enough fe i will do it ,,,anybody done this, or have ideas?

as per the Hotrod exhaust science article
the resonator has a function in the tuning of the exhaust pipe length .

removing it should DECREASE overall efficiency and reduce power output and fuel economy .
as per the article

it makes sense to me.