[christofoo]

Now I understand the advantage of the ducted, low drag cooling design. Are there any DIY build threads / pages on that approach? I want to think in terms of cost-benefit, it's easier to assess difficulty if it's been done already - bonus points if the benefits are A-B-A tested or CFD'd. This seems like a frontier of ecomodding.

But my calcs may still be useful, as a guideline it probably applies somewhat to both ducted and non-ducted designs. A good ducted design would have the advantage that the Cd is less affected by the opening, so variable blocking would be less of a concern.