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It makes sense that a delayed intake cam can result in reversion -- late valve closure into the upstroke pumping a small amount of charge back into the intake manifold and reducing compression. The late exhaust cam also gives a longer effective power stroke, giving a kind of Atkinson cycle used on the Prius.
Are non-hybrid cars factory-tuned that way? I guess with VVT the answer is yes, at each load and RPM the valve timing is adjusted to optimize performance or economy at that condition. But with fixed valve timing, the Atkinson reduced intake charge, increased expansion arrangement is supposed to kill torque and is the reason this is offered on Prius-style hybrids because you have the electric motor to make up the difference?
Maybe setting the cam one notch delayed from where I have it may compensate for engine deposits, restoring more normal compression from the carbon deposits, increasing economy by not having the knock sensor cut back on spark advance?
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