I know the 4 bolt will not allow for an internal WG, but why are there turbos that have a 5 bolt pattern but don't even have the option for an internal wastegate? It just doesn't seem to follow a pattern from company to company. For example, it seems that all the Garretts that have a 5 bolt use an internal WG, where as the Masterpower 5 bolt doesn't even have the option for an internal gate. I could just be making this way more confusing that it needs to be... it's just been a question I've had for quite some time, but haven't really found a simple answer. Thanks.

 

then master power doesnt have to provide a wastegate with the turbo and makes you buy one of their fake tial ones. You can also find garrett 5 bolt housings that dont have the wastegate hole on them.

 

So then what's the point of the 5 bolt design? Just seems unnecessary and really oddly shaped. I like symmetry! (like the 4 bolt)