What's so bad about that?

[Kevin McDole]

Richard,

Maybe I'm misunderstanding your question, but here goes ...

The turbo system is a closed loop consisting of the controller, waste gate, and turbo. The controller senses the upper deck pressure and positions the waste gate using oil pressure.

If you swap those lines, then you will get some "random" waste gate position based on the turbo line oil pressure - and the turbo will not receive the correct oil flow, but rather some "random" supply based on the upper deck pressure.

In summary, your turbo system won't work correctly, and this very well may destroy the turbo - if not the entire engine (with an overboost).