Temperature Measurement

Temperature measurement is performed with a K-type thermocouple. Thermocouples operate by sensing a voltage that is generated at the weld joint between two different metals that varies by temperature. You can actually build your own thermocouple with a welder and special wire (but Trashhammer says welding is pretty hard).

You have to index the voltage generated by the thermocouple against a known temperature. To do this we have a thermistor that is on the SBT Scaler board and connected to one channel of the A to D converter. Thermistors have a much narrower range that they measure - but they do a great job of measuring ambient temperatures.

Other types of thermocouples (other metal types) give you different temperature ranges. K-type are normally used because they do a nice job of 0-1000 centigrade.

Thermocouples are VERY non-linear. So they have to be corrected in software to rescale the incoming voltage and correlate it to temperature.

Our SBT/BT gauge has two terminals that are configured for thermocouple reading. If you do hook them up to a thermocouple and don't read a temperature - the first thing to do is to swap the leads. It won't hurt anything if you have them backwards.

We recommend using the thermcouple to read exhaust temp, but you could also use it to read intercooler temp or intake temp (or your own temperature - we recommend orally).

Note that the SBT/BT picture of the Exhaust manifold can be changed in the gauge menu to a picture of an Intercooler. These two pictures are animated so that they change color when heated.

page maintained by bcarpenter@roadragegages.com last updated January 31, 2014