As pointed out earlier, lower ambient temperature does not necessarily mean the temperature in the manifold (which is what matters) is any lower if the MAP is the same. It all comes down to the atmospheric lapse rate.
Fred, I read over the thread again and I understand what you're saying. It makes sense that if you bring it back to the same MAP, then the temperature should be the same. And like you said, there could be a possibility of a difference in lapse rate but I agree, if there is a difference, it would be small. Not sure why I didn't see it before. If we're all on the same page, so far it seems that a reduced back pressure at altitude is the only reason for the increased power or lower MAP required?
It seems then that the JAA book is wrong on that matter?
Fuel used does not equal fuel used in combustion.
Can you expand on that. I think under most conditions the fuel would be completely burnt, however, not always inside the cylinder and not always providing an increase in power.