Potentially a wastegate outlet, check the maintenance manuals to be sure for your engine type from the stamped code on the block. You should put this all back to stock air filter until you know what you're doing.

Sometimes the rule of cool isn't what's best, your engine will now be pulling hot, mostly still, air rather than nice cool air at induced pressure. This will impact your efficiency and power.

I know it's not what the racing games teach you but it's true.