Thanks for the explanation, krazy and amx1397.
Now i understand it's for drag strip purporses. And i think it makes sense there. Over here in germany we don't have that drag strip history, because we don't have public drag strips. We have the german autobahn which is is some regions still without speed limit. And there we don't have the overheating problems because of the airflow.
The colder air, the more dense the air = more hp
That's right. But if you cool down down the air, you need engine energy to do that. If you need more energy to cool down the air, then you gain from cooling, you don't have any effort. So for drag racing this may work, because you only drag for a short time and can use the previousely cooled down compressor and water.
Regards
Markus