This cant be right? Or is it? opinions please? Options

[KOU In3]

Chart half way down at the bottom.

the effeciency range of the turbo being pushed to its limits?

My guess is thats right, but even putting in 660's would solve it if the root of the issue is superheated air of a maxed out turbo?

660's will only solve a fuel shortage issue. Meaning if you are getting knock from running lean you would need the increased fuel. If the root of the issue is the superheated air, then you don't actually need more fuel.

The hot air is actually a smaller mass of air and would need less fuel than an equal 'volume' of cold air (not sure if my terminology is correct there but the theory is sound).

Bascily you want the most total mass of air. 22psi of hot air can actually be less actual air than 16 psi of cold air depending on the application.

Two things I can think of is the shaft speed of the turbo, its effeciency range (not just peak efficiency but where its actual power production actually drops off) and the quality of you intercooler set-up.

Hope that helps.

Oh, and that chart's been around a while. Not sure how much I buy into it as gospel. Good reference/rule of thumb but not the be-all-end-all IMHO.