[E4ODnut]

That's what I thought, but getting into that 2nd harmonic might be difficult on a slow turning engine.

Another thing. Lets take the 24" length as an example. At ~6000 RPM you get a 10% boost, at ~4500 RPM you get a 7% boost, at ~3400 RPM you get a 4% boost. What happens in between these peaks? It would seem that if pressure peaks, it should also valley in sort of a sine wave. Perhaps there would be negative pressure at ~5250, ~3950, and ~3000 in decreasing amounts. It might make for an interesting torque curve.