One of the basic myths is "it will flow better with XXXXXX (insert larger pipe 70% of the time).
Since we are ecomodding, we are trying to use the engine in the lower rpms. There is NEVER a time when a larger than factory size will be beneficial.
Thanks for providing the exhaust pipe size chart!
On my particular car, (02 infiniti Q45) there was a very large muffler in the rear. commonly refered to as 'the suitcase muffler'. It wieght about 40lbs. There were already 4 cats, 1 resonator and 2 mufflers beofre this last one. I removed it PRIMARIALY for some weight savings.
I could see where someone (with an older car or a top of the line car) could reduce some weight and still have a relatively quite exhaust. as long as they keep the piping at factory size.
here are some pics:
I have removed tj=he rear dual muffler and installed minis
I di remove the resonator...there was a crack developing and installed the x pipe.
that lead into the factory mufflers:
The rear is covered now with a rear belly pan