I've been meaning to fit an EGT gauge for a while just to see what the temperatures are in standard trim. Also as my car doesn't have a fuel computer I thought it would be good to use as an indication of how much load the engine was under so would indicate how much fuel is being used, much like a vacuum gauge does on a petrol engine. First the probe needs to be installed poking into the exhaust manifold so... Manifold and turbo need to come off. Note the nice swept shape of the manifold, this gives good gas flow. Part the turbo and manifold. Note the turbo intake aperture is larger than the manifold exit aperture. This restricts and disturbs the airflow into the turbo. Having decided on a suitable place drill and tap the manifold and fit the thermocouple ferrule. This will project through slightly so grind the excess back. Whilst at it I decided to create a bell mouth for the gasses leaving the manifold for better gas flow into the turbo. Install the thermocouple about 1/3rd-1/2 way into the gas stream. Thread the cable through to the passenger cabin and connect to the gauge. I've only been able to do this temporarily for now as the cable is too short, so I've ordered some. Having taken it for a drive I can say it works brilliantly and is sensitive enough to detect such engine loads as switching the lights or vent fan on...and especially putting the gearbox in gear or turning on the air-con.. Idling sees temps of about 108c tonight, but 140c earlier when fully warm, and maxxed out up a steep hill gives ~715c and a 777c momentary peak... No room for adding extra fuel there..