The effective ratio is the same as static once the engine reaches 100% volumetric efficiency. If, for example, 8.5:1 dynamic was the cat's meow for pump gas, then why not build every engine for 8.5:1, and close the intake valve at BDC. I can hear the keyboards pounding already. But Mike, but Mike, you have to close it later so the flow inertia continues to fill the cylinder after BDC, and there is still adequate curtain area at BDC to flow air to fill the cylinder effectively.

Well, EXACTLY! Inertia comes into play as soon as the engine fires off, and there are too many factors involved to "shoot" for a given DCR. The VVT engines, as Brad stated, are computer controlled to run higher static numbers, make more power, and be more efficient.

In short, the engine doesn't give a rat's patootie when the intake valve closes. It only knows how much of a charge is in the cylinder. Make peak torque at a higher rpm, have less chance of detonation. Even the exhaust system will have an effect on peak torque.