Compression - How much is too much?

[XJS]

NoHachi Wrote:

XJS Wrote:If you pump up your compression ratio, the engine will consume more air, so the ECU will inject more petrol, simple is that.

Ehm.. it doesn't consume more air at higher compression ratio's..its the exact same amount of air, compressed to a higher pressure.

Fueling stays exactly the same. Any problems will be on the ignition side of things and they will be difficult to detect without a decent knock-sensor.

Higher pressure itself doesn't give any more power, more air (and fuel) will. Hence the question: why the higher compression engines has more power, if they burn exactly the same amount of energy? Why all stronger engines has high compression ratio, some enabling the use of high-lift big overlap cams, if they will suck the same amount of air?