Quote:
by far the best location for installing an EGT sensor is in the exhaust manifold, upstream of the turbo-charger exhaust turbine inlet. As the exhaust gas expands through the exhaust turbine, the pressure and temperature of the gasses reduces markedly. However, it is the hotter upstream temperatures to which the vital turbo components are subjected. That is, the turbine housing, turbine blade tips and wastegate valve 'see' the hotter upstream gas, which can heat them to damaging temperatures.