Comparing N02 to PSI

[PKRWUD]

Mach 1 is right. At sea level, atmospheric pressure is 14.7:1 psi. For every pound of pressure (boost) you create above that, you increase the displacement of your engine. If your engine displaces 302 cubic inches at sea level (14.7:1 psi), then with 15 pounds of boost, which would double the atmospheric pressure, your engines displacement would also double, and become 604 cubic inches. The horsepower won't necessarily double, but the displacement does. Nitrous is just a way of adding extra oxygen in a controlled manner (the nitrogen controls the burn rate of the oxygen, so it doesn't just explode like pure oxygen would). Nitrous is more like having higher compression.

Take care,
-Chris