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Phimosis

Something doesn't add up.

Air goes in at one atmosphere (14.7 psia), gets mixed with gas at roughly 11:1 ratio, makes 277whp.

Add turbo & intercooler, add 6.2 psi of 'boost' (20.9 psia), add 42.2% more fuel to match the 42.2% more air (20.9psia / 14.7psia = 1.422) and at same 11.0:1 air/fuel ratio and you should, in theory, get 42.2% more power.

I say in theory, because you end up getting less than that. There are frictional losses from turbulence as flow velocities in intake runners go up, there's losses from backpressure that the turbos create, there's some loss in air density from increase air intake charge temperatures, etc. Regardless, at 6.2 psi boost an otherwise stock 370z should only make 394 whp. Likewise, 8 psig would get you to 428 whp and it should take 9.3 psig to get to 452 whp.

The other ways you can squeeze more power is by more using ignition advance, leaner a/f ratio or modify the engine/intake/exhaust. Using a lean burn or ignition advance will cause detonation and aren't viable in a turboed engine.

So something doesn't add up. Any ideas?

-Phim