hey guys there is another factor u gotta think about the frictional area of the pipe Example one : 2.5" pipe 1 foot long frictional area = 94.24" square Example two : dual 2.5" 1 foot long frictional area = 188.48" square Example three: 3.5" pipe 1 foot long frictional area = 131.94" square if u compare a dual 2.5" (9.818 square inches) agains a single 3.5" (9.622 square inches) system the cross section is nearly the same but in a single 3.5" the exhaust gas got less area to " rub " on compared to the dual 2.5" so it will flow better than a dual 2.5" Cheers MIX
