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Part of the reason uncorked rotaries are so loud is that some fuel leaves the engine unburned and that fuel is still burning in the exhaust. That burning fuel is lost when the engine is naturally aspirated, but when you bolt on a turbo it's using those burning gases to turn the turbo. You can put pretty massive turbos on pretty small rotary engines, and they have no problem spooling them.
Pinger hit on the breathing aspects of reciprocating valves. The other theory is the power loss of driving the valve train. Less power loss within the engine means more power to the rear wheels. The idea is to strive for the best engine efficiency you can get and eliminating the cam,lifters,valves,maybe push rods and especially the springs helps do that. 2 cycle means power on every downstroke without valvetrain drag. The Detroit almost gets there but still has to deal with those aggravating reciprocating valves and all the pieces to work them. If I could get my hands on a V671 Detroit I'd drop that in ol Smoky in half a heartbeat.
I hear what you're saying, but I'm still more inclined toward the straight shot from the trochoid (or cylinder in the case of 2T) to turbo being what the turbo likes. It is a significant contrast to having to wait for an exhaust valve to open, worm a route around it, then negotiate a close to 90 degree bend.
The opposed piston configuration gives the benefits of uni-flow scavenging without the valves that Detroit Diesel used. In 1925 Fiat had a six cylinder gasoline OP engine that made 150hp from its 1.5 litres. A variation on the theme that avoids the practical difficulties of OP is the split single (aka Twingle) which in essence is an OP engine bent double in the middle such that a single crankshaft can be used. There were a few smallish ones in production in Europe in the previous century deployed in small motorcycles and with the more advanced materials we now have, could be viable again as a homogenously charged (avoiding the complication of direct fuel injection) engine IMO.
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Damn! I've got to get the sound fixed on this POS laptop. It's a purdy thing but I couldn't hear it and that's the best part of a Detroit. And they pull like a team of mules. Only thing sounds better than a V6 Jimmy is a V12 but I think the V6 sounds even more pissed off.
You have it spot on but for the valves. Invariably split-single engines (ignore the Scuderi split-single - it's a different animal) are piston ported and as such have the benefits of opposed piston engines namely a large spacing between inlet and exhaust ports (to minimise charge loss) and, the full circumference of each cylinder for said ports - unlike loopers and cross-flows which have to share the circumference. They (split-singles) can also, like OPs, be configured with asymmetric port timings and - I think - with less torsional vibration issues than OPs. Both (OP and SS) permit long strokes (good for 2T) but without the colossal piston speed of a single piston - and the difficulty of con-rod clearance at the cylinder's base.
Seems it has... or rather, it has used a rotary as a range extender in an EV. Pretty much what Audi proposed but abandoned.
