Wastegates act as a pressure relief component on turbocharged vehicles. Most factory fitted turbos and even aftermarket turbos have a built in internal wastegate in order to relieve boost pressure when it gets to a set amount. But, when running certain larger turbos or specific setups, they do not come with these built in valves. Which necessitates an aftermarket version to release/divert that pressure. Technical aspects aside, external wastegate setups sound extremely cool, especially when venting to the atmosphere via a naughty screamer pipe.....