While I'm waiting for my gauges to arrive from I've been chewing over the pre/post turbo thermocouple debate and I'm leaning towards post turbo and here is my reasoning:
The thermocouple is only measuring the exhaust gas temperature which as we know increases with load and
boost so it will cool when the engine is left to idle as the exhaust gasses are then much cooler.
However in pre-turbo position it will cool much quicker than the turbo giving the false impression that the
turbo is cool enough to safely shut off the engine.
Siting it post turbo means the relatively cool gasses coming from the engine at idle will be heated by the still extremely hot turbo housing so it will register a higher temperature for longer giving a more realistic indication of the true turbo temperature?
I'm certainly no diesel expert but just applying the laws of physics here.....the small amount of metal in the thermocouple itself will cool down much quicker than the large turbo housing.....or am I missing something here?
The thermocouple is only measuring the exhaust gas temperature which as we know increases with load and
boost so it will cool when the engine is left to idle as the exhaust gasses are then much cooler.
However in pre-turbo position it will cool much quicker than the turbo giving the false impression that the
turbo is cool enough to safely shut off the engine.
Siting it post turbo means the relatively cool gasses coming from the engine at idle will be heated by the still extremely hot turbo housing so it will register a higher temperature for longer giving a more realistic indication of the true turbo temperature?
I'm certainly no diesel expert but just applying the laws of physics here.....the small amount of metal in the thermocouple itself will cool down much quicker than the large turbo housing.....or am I missing something here?