"The BOV/dump valve debate will rumble on throughout the worlds forums for years to come and it seems to me that no-one has the complete answer". The reason for this is that some people read, and believe, too many posts written on too many forums by people (self proclaimed experts) that do not have the slightest idea about what they are talking about. To be honest, I am bored of reading over & over again every 'Boy Racers' take on the whys & wherefores of forced induction. The basics Firstly, a wastegate acts on the hot side of the turbocharger and serves to regulate the amount of energy recovered, from the exhaust gases, by the turbine. When the wastegate is open, exhaust gases effectively by-pass the turbine and there is (relatively) no energy transfer