ShopinJA Classifieds

An exhaust gas temperature gauge (EGT gauge) is an automotive meter used to monitor the exhaust gas temperature of an internal combustion engine or rotary engine in conjunction with a thermocouple-type pyrometer. By monitoring EGT, the driver/tuner can get an idea of the car's air-fuel ratio. At a balanced air-fuel ratio, the exhaust gas temperature is lower than that in a lean or rich air-fuel ratio. High temperatures (typically above 1600 degrees F) can be an indicator of dangerous conditions that can lead to catastrophic engine failure.

This meter is most used in tuning turbo-equipped cars. If the sensor is installed at the manifold collector before the turbo, the turbine inlet temperature can be monitored. If the sensor is installed after the turbo, the exhaust temperature can be monitored. Because EGT will typically drop 200-300 degrees F across the turbine, installers in general will try to put the thermocouple as close to the cylinder head as possible to give a true reading that will require less mental math to read properly, and a reading that will react faster to the engine's condition compared to an installation after the turbo.

Advanced racers will use EGT gauges in combination with a wideband oxygen sensor to 'lean' the fuel ratio a bit to safely raise the temperature for more power.