Intercooler efficency is why drag cars all use liquid units. An air unit can never get the intake charge below ambient, or even close usually. But combine the heat absorbtion capability of water along with the fact that it can be cooled with ice, shows just how much HP can be given back to the engine by removing all that heat. When you look a the numbers, its not too hard to see where the 1,000 hp 4 cylinder drag engines get that hp from.