Turbo porting, fast and furious

So, I had a problem with my turbo overboosting. Basically this means that even with the wastegate wide open the boost still builds so it is out of control.

This is not a good thing, because too much boost can result in engine damage.

I had temporarily addressed this by installing a exhaust dB killer (a device that reduces the noise a bit by constricting the exhaust at the outlet). This results in slightly higher pressure in the exhaust and it is the pressure difference between the two different sides of the exhaust turbine that provides the drive to the turbo.

Anyway, that was a short-term solution and did work, but it isn't ideal. The whole point of turbos is to get lots of boost and lots of boost when you want it. Decreasing the efficiency of the turbo would (in theory anyway) make boost come in later and generally make things more laggy.

So, I hit the internet and discovered that I needed to make the wastegate more efficient. This is done not by changing the wastegate, but buy making it easier for the gases to whip through the hole. As expected the casting was crude, so my die-grinder, a carbide bit and 20minutes was all that was needed to open up the flow paths so as to allow the gas flow to more easily get through the wastegate (when it is open).

Here are a couple of photos, post port (none before, sorry).