Unless I'm missing something, both Dynomax mufflers listed in the article are offset inlet and outlet. Those are designed differently inside. The center outlet design is the one that looks restrictive.
Not really - they simply cross-flow internally. The sCFM #'s for offset/center, & offset/offset are about the same - around 410 sCFM's for both 2.25" & 2.5" Super Turbo versions. Still, Super Turbos do not do much "tuning" of the sound, but they do more than Ultra Flows. Ultra Flows are like oval glasspacks & other straight-through mufflers. Flowmasters TUNE the sound, but they do not flow impressive sCFM's because the plates internally cause quite significant restrictions.
