im thinking about building a pie cut exhaust system for a 09 softail,
but i have some size questions

1) i don't care about speed, but it must be loud and mean. so what is the best diameter to go with?

2) what size diameter pipe for the flange? like you can see in the photos the pipe is smaller at de beginning of the pipe

 

throw some hooka headers on it and be through with it.

 

Check out our new report on Harley exhaust. You might find it interesting and rather helpful when it comes to exhaust and power as well as sound.

Harley Exhaust- How it Works - Myths and Facts

Taken from the report-

 

 

If they are the same length, then yes, the full 3" exhaust system is going to be louder than a 2" pipe.