100% on the money!! (and I found something to talk about!!)
V-twins valve geometry have a minimal % of overlap where both valves are open. Straight pipes and over baffled pipes fail the basic designs by not allowing the exhaust gases room to create a vacuum from that overlap which pulls more air into the chamber thus making a bigger boom in the chamber giving you more HP.
That extended valve opening works with the same principal as an automatic pistol chambering a round works, thru spent gases.
A 2into1 or even a false 2into1 creates that suction.
Me - I have a set of hooker exhaust on stock pipes with adjustable baffles. Left side closed all the way, right side open - false 2into1. Give me that throaty low rumble, except when I nail it and blue flame shoots out, front wheel jumps off the ground and everybody takes pictures while I ride a full dress wheelie through 2nd gear!!!
(gotta rejet and retime, oh did I mention the 110 octane race fuel available at the local Sunoco??)
<|:-)~~
Exactly, which is why I have have the stock crossover pipe on my Sporty with modified slip-on baffles. I have all the WOT I need, but with enough reversion that I haven't sacrificed any mid-range torque to get it.