Hey guys, id figure that i would give my question a shot down here. Im currently transplanting a TL-S muffler on my I-4 accord that already has a greddy evo catback, which has 2.25" piping. I was planning to chop the piping near the rear axle back and have a shop weld and pipe a y-pipe for a dual TL-S set up. My question is....what size piping should i have leading to the mufflers? Some people have done 2.0", but ive heard people telling me that i should use 1.25" to accomadate both mufflers. I understand the ideal piping diameter for the accord is a 2.25" with a single muffler. Anyone know what size pipe i need to use for a dual to the mufflers? (for best performance/ minimal power loss)

EDIT: This may help...(from past thread)
The astute exhaust designer knows that you must balance flow capacity with velocity. You want the exhaust gases to exit the chamber and speed along at the highest velocity possible - you want a FAST exhaust stream. If you have two exhaust pulses of equal volume, one in a 2" pipe and one in a 3" pipe, the pulse in the 2" pipe will be traveling considerably FASTER than the pulse in the 3" pipe. While it is true that the narrower the pipe, the higher the velocity of the exiting gases, you want make sure the pipe is wide enough so that there is as little backpressure as possible while maintaining suitable exhaust gas velocity. Backpressure in it's most extreme form can lead to reversion of the exhaust stream - that is to say the exhaust flows backwards, which is not good. The trick is to have a pipe that that is as narrow as possible while having as close to zero backpressure as possible at the RPM range you want your power band to be located at. Exhaust pipe diameters are best suited to a particular RPM range. A smaller pipe diameter will produce higher exhaust velocities at a lower RPM but create unacceptably high amounts of backpressure at high rpm. Thus if your powerband is located 2-3000 RPM you'd want a narrower pipe than if your powerband is located at 8-9000RPM.