[svxistentialist]

Hi Tony

You are reading the sheet wrong, but no need to apologise, I see where the dilemma is.

The 456 you are quoting, that does not refer to temperature. That is a measure of Cubic Feet per Minute, how much air the blower has to shove in there. The amount of hp the engine produces is directly related to how much oxygen we can get it to ingest.

If you look at the "with cooling" 340 hp chart, 340 is the hp you want to extract.

With 80% cooling 456 CFM of this denser, cooled air is all that's required to produce this horsepower.

Directly beneath this figure you will see 530 CFM. This is the amount of heated [non-cooled air, the compressor heats it] air the compressor would have to force in there to get the same horsepower.

Because of gas density, it only requires slightly more pressure at 9.4 lbs to get this correct amount of cooler air into the engine and give us 340 hp as opposed to 290 hp uncooled.

Or looked at another way, cooling is a cheap way of getting more oxygen in there. Without the cooling, the blower has to work much harder to produce the same horsepower, pumping 530CFM where it would get away with only 456CFM of the cooled charge.
[Plus of course the extra temperature will give excessive heat in the cylinder, adding another problem]

I hope that's put clearly and you see what I am getting at.

Joe