when does turbo kick in?

[87gnstock]

What determines on a bone stock gn with the stock chip when the turbo kicks in? Is it the throttle position or the gear that the transmission is in?

 

[tazgn]

Engine Loading I believe. It's all about exhaust gas pressure versus intake pressure. The chip can control how high the boost goes before it will limit it with the wastegate, and can control when the engine loading (by controling timing/fuel) to some extent. And obviously the torque converter will control engine loading as well and what RPM it loads the engine.

Derrick

 

[UNGN]

Spool is directly proportional to massflow through the engine.

When the given massflow for spool is achieved, the turbo will spool.

Load alone won't make a turbo spool: load down the engine at 1000 RPM and the turbo will never spool.

The reason an unloaded engine won't spool the turbo is the massflow through an unloaded engine is not enough to spool the turbo. (It doesn't take much throttle/fuel to redline an unloaded engine)