That would require me to own a data logger, rather than just apply the common sense that tells me that if you're not burning fuel, you're not making power, but when you're spinning twice as fast (at constant pressure) you're moving twice the air.

There are 2 parts to actual power generation:-

1) Air flowed

2) Fuel actually burnt in that air within the engine. This is not always the same as fuel flowed, hence (uncatalysed) exhaust HC content, and soot from (mostly older) TDs in high throttle, low revs situations.

That's very interesting. My engine consumes more air at 4_000 rpm on a closed throttle than at 2_000 on full throttle, but burns no fuel on a fully closed throttle at anything over 1_200, so makes no power.

Agreed that with a closed throttle you are not generating any power but what you say above is completely wrong for my car, if you have no data logger, how do you know this? Are diesels so different to petrol?

On my car at 4000 rpm with a closed throttle, the air consumtion is about 8g/s

and on 2000rpm with a wot, its consumption is 50g/s.

So the liquidOCTAVIA shows the correct power value when the throttle is open rather than closed, however given the scales, closed throttle reading are barely visible.

Are you interested in seeing some plots?

For diesels I need to see a lot more plots to get the calculations right.