Gt30 Turbine Housing Alternatives

[scotty nm35]

Internal gate is the issue, the gate hole can't flow enough and most of the exhaust goes down the nozzle through the turbo as it's easier.

Winding too much preload into the actuator can cause this issue too. It isn't a good way to raise boost as it limits the actuator's travel. Split dumps can also limit wastegate flow.

You may be able to die grind the path into the wastegate, and remove any restrictions to flow to improve the situation but that just makes more airflow which causes it to max out again. External is the only answer.