That Exhaust pressure pulling the springs probably has a lot to do with turning the exhaust pulse. Shoot it straight out for less energy transmission to the pipe. Air at that speed is heavy.
25:30 How would it have enough pressure? You are not exactly wrong when you say the pipe is "full" But it is not exactly what is happening. IF you want to really understand it, go look up water hammer in plumbing pipes and the reasons it happens because it is the same phenomenon. For a brief instant the pipe behaves like it is shut and that shut "door" moves down the pipe but it takes time. Meanwhile the pressure can build without restriction for a short time until the pressure wave moves further down the pipe. You could almost say the gas in the pipe is like a piston that has to be pushed down the pipe, it will go but it takes some time and the pressure can grow in that time. It might seem bad but that pressure slug is also the source of the negative wave that comes back later to empty the chamber and get the intake moving early. It boggles my mind that after all these decades no one caught on to how critical this phenomenon is in high speed engines. I left the game in the late 80's and I knew about it then. I thought for sure someone would see it and run with it. I thought it was the future and here we are 30 years later and NO ONE got it. The only one who is even close to it is Vizard. I might do something with him about it. We'll see.
Well, this was very interesting indeed. I was with you right up until the COVID shit started. Then I tuned out. But anyway, I really enjoyed the topic. I didn't absorb all of it of course, but I wasn't lost either. It made me think "I wonder what kind of system he would draw up for oh, say, a stage 2 modded Victory Vision?" Ahem... HA! In fact I liked how your free-hand presentation approach involved different aspects of what an engine actually is at its most fundamental level. Then you follow it through and tie in the exhaust system's important part in the whole thing. And it brought me back to the 2-stroke GP days and how absolutely critical it was to build a matched exhaust. I think they even called it a resonator. Tuning to resonance. That place of balance and maximum power potential. The math behind that is waaay out of my league but it's pretty cool! Thanks again for sharing your knowledge. I didn't get all of it, but I enjoyed all of it!
