1200rc, I know you didnt mean to say the wastegate vents air back into the motor, did you?

For anyone who is interested:

An internal wastegate is combined with the exhaust turbine housing. The internal wastegate will limit the boost supplied to the motor but will not control the boost, if you know what I mean. The internal wastegate will open at a set limit and send the wastegate air straight into the turbine outlet air. In other words it takes some of the exhaust gas and bypasses the turbine wheel but vents it to the other side where the exhaust gas goes.

This is not an ideal setup as the excess wastegate air will cause more turbulence at the exhaust turbine wheel reducing the flow. So you can create a pipe to run off the internal wastegate that diverts the wastegate air further down the exhaust pipe to reduce turbulence. Or you can not plumb it back into the exhaust but vent it to atmosphere, this is very loud. It is called a "screamer pipe", for obvious reasons.

An external wastegate works similarly to an internal one. It is mounted on the exhaust/turbo manifold before the turbo, but obviously is not part of the turbo. It needs a boost line from the compressor cover that will open the wastegate.

I will stop dribbling