Maybe I'm missing something, but I fail to see the 'benefit' of a DCR figure. For instance, is it not going to vary at different rpm? As volumetric efficiency changes thru the rpm range, different amounts of fuel/air will be drawn into to the chamber for compression. So, at which rpm do you choose as a reference? Also, using the 'advertised duration' will give varying figures. If you use a Comp Cams hyd, they usually quote their hyd cam figures at 0.006"; Crane often use 0.004" . Could get a different DCR for essentially the same lobe profile because of a difference in the quoted 'advertised duration' figures. Two identical cams used in identical engines except one has ported heads, will have different DCR's because you would expect the ported heads to flow more air; but the calculator would show the same DCR for each engine.
The very fact that it is called 'dynamic' means that it is changing. And that is exactly what it is doing, constantly: changing. I feel there are too many variables involved to get DCR from a formula or equation.
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