Panars - thanks for the answer. The results indicate that the round bar is torsionally much stiffer (~10X for the dimensions I used) for a given cross-section area than a flat bar is. Is that what you would expect?
This is for an autocross race car suspension - I have a 22mm solid round torsion bar (sway control). I have run the dimensions through a "beam section properties" online calculator that outputs the properties listed below.
I would like to fabricate a flat torsion bar to achieve 50% greater...