EGT Probe
02-12-2006, 12:18 AM
#1
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Join Date: Jul 2005
Posts: 254
EGT Probe
Alright, do you guys just use any kind of EGT probe for your #3 exhaust? How long does these suckers last with expreme heat range like that. Just researching before getting one of these suckers and if anyone had any recommendations. Thanks!
02-13-2006, 07:17 PM
#5
1.0 BAR
Join Date: Feb 2004
Posts: 311
Re: EGT Probe
"In the temperature measurement industry their are two basic types of measurement devices. The first is called resistance temperature detection or RTD. This type of device is basically a very fine wire encased in a container, or bulb. As the temperature of the bulb changes, the electrical resistance of the wire changes. By passing a small current through this wire and measuring the resistance, the temperature can be determined. This is the method used by your Digatron cylinder head temperature gauge. And as any of you knows who've used a CHT GAUGE for any length of time, these CHT sensors, while accurate, are relatively delicate. Rough service (like on a kart) is not generally recommended. They also have a temperature limit that makes them unsuitable for use measuring EGT.
The other major means of temperature measurement is the thermocouple. The thermocouple is a unique device. There are several different types of thermocouples, using different materials for different temperature ranges, but they all operate by the same basic means. A thermocouple consists of two wires, of different materials, welded or fused together. For the temperature range we are most interested in, the type K thermocouple is most suitable with a maximum temperature of 1900 degrees Fahrenheit. In a type K device one wire is an alloy called CHROMEL®*, and the other an alloy called ALUMEL®*. A small portion of each wire is exposed and the two are welded or fused together. That assembly is encased in an electrically insulated sheath and the other ends of the wires are connected to a very sensitive voltmeter. Now here's where the thermocouple differs from the RTD. When the fused end of the thermocouple wire is heated, it generates it's own current. It's only a matter of millivolts (that's one one-thousandth of a volt), but the voltage generated is an accurate indicator of the temperature of the end of the thermocouple. A real bonus for motorsports is that these thermocouples are remarkably sturdy and reliable. With no delicate parts to break, unless you exceed their maximum temperature, they're pretty hard to damage. In fact, every gas- fired furnace and water heater uses one to tell the gas valve that the pilot flame is lit."
Autometer is a K type.
The other major means of temperature measurement is the thermocouple. The thermocouple is a unique device. There are several different types of thermocouples, using different materials for different temperature ranges, but they all operate by the same basic means. A thermocouple consists of two wires, of different materials, welded or fused together. For the temperature range we are most interested in, the type K thermocouple is most suitable with a maximum temperature of 1900 degrees Fahrenheit. In a type K device one wire is an alloy called CHROMEL®*, and the other an alloy called ALUMEL®*. A small portion of each wire is exposed and the two are welded or fused together. That assembly is encased in an electrically insulated sheath and the other ends of the wires are connected to a very sensitive voltmeter. Now here's where the thermocouple differs from the RTD. When the fused end of the thermocouple wire is heated, it generates it's own current. It's only a matter of millivolts (that's one one-thousandth of a volt), but the voltage generated is an accurate indicator of the temperature of the end of the thermocouple. A real bonus for motorsports is that these thermocouples are remarkably sturdy and reliable. With no delicate parts to break, unless you exceed their maximum temperature, they're pretty hard to damage. In fact, every gas- fired furnace and water heater uses one to tell the gas valve that the pilot flame is lit."
Autometer is a K type.
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