I would concur about the backpressure in real life. Right now my header is broken at the first y pipes and it's shooting flame right out the 2 holes. It felt fine with good exhaust but it really opened up high rpm with the busted header. Floor boards get pretty hot though
. My 22r on the other hand seems to thrive on backpressure. I actually picked up mileage and it pulls passes a little better with a stock muffler and 1 3/4" tube than it did with a flowmaster 44 and 2 1/4". Weird.
Also, my 20r loves to run on junky 85.5 octane, whereas the 22r needs at least 87. The carb is small on the 20r, but the jets are HUGE compared to the 22r carb and it clearly runs richer in stock form.
The way it was explained to me regarding the smaller ports and valves, is that while it's moving less volume at once, what it is moving is moving faster, kind of like when you spray water out of a plain garden hose or when you put a restrictive end on it. This effect according to my machinist will create more usable torque. This is a second generation race car guy who has done a bunch of fancy port work and got to see the results in real time.
Obviously more flow is more flow and the practical application of this depends on a great many other things like the shape of the ports and all that but I can verify his theory in real life comparing my 22r against the 20r. The 22r maybe has more, but the 20r does it with more pizazz.
The popular 20r/22r hybrid must be basically taking what the 22r has and making it act like the 20r.
