The most notable difference between a thermocouple and an RTD (Resistance Temperature Detector) is the principle of operation. A thermocouple operates on the principle that two dissimilar metals joined together will produce a voltage related to a temperature difference. An RTD, operates on the principle that electrical resistance of certain metals changes in a predictable way depending on the rise or fall in temperature.
Q: I want to buy the SuperLite Digital Pyrometer. You sell one with Analog Output. What does "Analog Output" mean?
A: The meter with the “Analog Output” option has a linear 0 to 5 VDC retransmitting output. This 0 to 5 VDC output voltage changes in proportion to the temperature reading on the digital display.
Customers who choose the meter with the Analog Output option typically are connecting this output to another device, such as a data logger or data recorder.
A general consensus would be 1 inch to 4 inches from the exhaust valve or if you don't know the location of the exhaust valve place the EGT probe 2 to 4 inches from the flange attaching the header or exhaust manifold to the head. Please keep in mind that not only is consistency in distance very important but centering the probe in the exhaust flow is as well. Plan this out before you start drilling holes! See other information at www.thesensorconnection.com
A quick way to check the EGT probe is to disconnect it from whatever device you are using to read it & put an ohm meter across both output wires (the wire colors are usually red & yellow). If you get an open reading then the probe is probably bad. If you get somewhere between 3 to 12 ohms then it may still be okay.
Start with the compression fitting body placed on a table vertically with the large NPT thread down. Insert the compression ferrule in to the compression fitting body with the conical side down into the small thread there is a matching mating surface. This creates a perpendicular surface (flat) at the top of the compression fitting. Then the smaller shouldered washer is laid on top with the conical side pointed up.
Customer Question of The Day:
I am hoping you can help I have a audi rs4 b5 2001 model it keeps coming up with a fault code with the egt sensor 2 short to ground will you be able to supply an egt sensor for my vehicle and if you can what would the cost be?
The easiest way to check an EGT probe out at 2 temperature points is:
A customer recently purchased a new 3/16" Diesel & Bio-Fuel EGT probe from us, and after installing, found it was reading about 200F lower than their old probe. After some emails back and forth we learned that the probe they replaced was also an enclosed tip probe but was smaller in diameter and about 50% shorter than the new probe.
I have a Mercedes turbo diesel and want to monitor the exhaust temperature and the temperature of the intake air
I have a Mercedes turbo diesel and my idea is to monitor both the exhaust temperature and the temperature of the incoming air in the intake manifold. Is there enough range on your EGT probe to measure also lower temperatures (min. about -10 Celsius)?
Q: I am looking for several EGT sensors for tuning a normally aspirated 2.3 L gasoline engine with 1 5/8” exhaust tubing. Are there any available guidelines about what size EGT probe is recommended, 1/8”, 3/16” or 1/4”?
A: We find that, for most applications, the 3/16” EGT probe is suitable. It’s our most popular probe, with nearly 75% of the probes we sell being this diameter.
Typically it is the center of the exhaust stream. This is not necessarily the center of the runner through the exhaust manifold or the header tube. The exhaust stream is dictated by flow rate, bend radius, the angle of the valve in relationship to the exhaust port, port configurations and other factors.
Q: I was wondering if you could guide me to where I may find some charts referencing EGT's.
Marine Engines are critical components to maritime vessel operations either for propulsion, power generation or auxiliary machinery operation. Typically these systems employ diesel engine management systems that rely on sensor inputs to manage operating performance for efficiency and shutdown to prevent catastrophic engine failures.
The easist way to identify your CHT sensor thermocouple type (or most any thermocouple for that matter) is to look at the colors of the wire jacket insulation.
But in some cases, the wire jacket insulation has been stripped away or is frayed & the colors are not obvious.
There are many factors to the "accuracy" any sensor. The most important aspect is what accuracy is needed to satisfy the actual requirement and the evaluation process to get there. Typically if your EGT sensor is within 1% to 5% of the actual temperature will satisfy most requirements. The major factors are probe accuracy and the indicator accuracy, taking these both in account will give you a close estimate of the actual temperature you are reading from the indicator(s).
Please explain the difference between Type K & Type J thermocouple CHT (Cylinder Head Temperature) sending units?
The primary differences between the two thermocouples are:
If you already own a gauge it is important that you use the correct thermocouple sensor type, otherwise the result will be incorrect CHT temperature readings due to mismatched sensitivities.
If I place only one EGT probe in the collector will I get an average temperature across all of the cylinders?
One EGT probe placed in the collector will measure the leanest (hottest) running cylinder. For a quick test of which one that is you can do the following:
What we suspect is happening is that the EGT probe has developed a “false junction”.
The primary measuring junction of an EGT thermocouple probe is the tip. This is where the 2 wires meet & are welded together. If these two wires touch at any point other than this junction before it plugs in to your gauge or controller then this second junction would be the “false junction”. The result is that the temperature reading becomes an average of the two junctions.
I want to drill & tap a hole in the manifold & thread in the Compression Fitting. What tools will I need?
We recently created an NPT Compression Fitting Technical Guide.
The guide includes detailed information about the compression fitting dimensions, threads, ratings, assembly, and installation.
You can download it from here: