This may sound stupid, but ive heard the phrase before but dont know exactly what is meant by an "Internally Gated" turbo.

To my simple mind, the majority of turbo's would be internally gated (ie, the turbo's you would get off the shelf, GT28, GT30 etx...), your more custom turbo's may be externally gated, is this right or am I way off the mark ?

How can you tell by looking at a turbo if it is internally/externally gated? I presume if the actuator arm leads to the wastegate on the inside (by the compressor housing?), then it is "internally gated" ?

I presume this is intenally gated :

 

and also this

 

You're right with what you've said.

 

As per what you have said, with an external gate its a completely seperate item which isnt part of the turbine housing, its sat seperately on the manifold, like my one here:



Where its mounted to the manifold totally seperate to the turbo.

 

Why have 2 types? Does one have any advantages over the other?

 

Internally gated is more comact, external is more flexible, depends what the design goals are as to which is better, most circumstances you could get away with either.

 

More precise boost control with external type. More expense as well.