[ttoyoda]

Well, I don't have time to waste watching the whole series,

So you have no idea what the series is about or what data is presented. Excellent.

and the later timing theory wasn't discussed in that one video above.

Durrr.

Flow obstructions are not the same thing as pumping losses -- oxygen sensors don't cause pumping losses.

I never said they did. Oxy sensors would be un-needed in a system that ran lean. They would have to be disabled in order to let the car injection system run lean.

In an unmodified engine, later timing would cause worse performance overall, causing less useful energy to be extracted -- the temperature of the engine might go down, but the temperature of the exhaust would be higher, so the efficiency would be worse. Timing is always BTDC because flame front travel is not instantaneous; you get the maximum energy extraction if the combustion pressure is not "chasing" the piston down, as would happen with late timing.

No kidding. But we are talking about doing modifications, and the whole point is reducing parasitic losses. All of this is dealt with in the videos you cannot be bothered to watch. So I cannot be bothered with explaining it to you.