Egt Question

[john]

I am probly going to install a etg gauge in my car soon. I am thinking about running a probe off the #1 and #2 cylinders to get a better idea of how hot it is. The question is about wiring the two probes to the gauge. Could I just splice the wires or thermocouples together? Do the thermocouples send voltage to the gauge or does the gauge convert the tem to voltage?

How would I moniter the two cylinders off one gauge?

[1ViciousGSX]

Just get a DPDT (double pole, double throw) switch and wire it so that you can switch between the 2 sensors.

[AJ]

Why not just monitor the 1 runner like everyone else. You just monitor the one you need to keep an eye on.

[FORSFED]

I've seen gauges that use two probes and have a dual digital readout for egt's. They are primarily used on snowmobiles and four-wheelers, but would probably be what you're looking for if you're trying to monitor both at the same time. Due to how the thermocouples work and are constructed, I don't know if it would be a good idea or not to just use a switch, could affect the readout maybe... I've never done it before, so I couldn't say for sure.

[LightningGSX]

Its more complicated than that.The voltage produced by a thermocouple is a difference in temperature between the hot and cold junctions, the hot junction is the part that mounts in the exhaust, and the cold junction is where the wires hook up to whatever the are hooked up to(thats not made of the same materials as the thermocouple).So unless the relay is at the exact same temperature as the gauge, there will be an error in temperature, not a huge error, but there is error.There is a temperature sensor inside the gauge(or whatever the thermocouple plugs into) that reads temperature for the cold junction compensation, you'd have to move this sensor to the relay(so it measures the temperature of the relay) for it to be totally accurate.

[LightningGSX]

Or you could attach the relay directly to the gauge so it is in thermal equalibrium with the gauge.