UBG-16 questions

Archimago

Archimago

Pre-takeoff checklist
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Archimago
I am having a UBG-16 installed in our Grumman AA5 so I can monitor CHTs and EGT's --I toyed with the idea of getting the CGR30P... as in had it in the cart and hovering over the check out button but decided I would rather use the price delta towards an IFR GPS...

First question is regarding the probes. I have heard that the EI probes will read a little cooler then the JPI probes but I don't know by how much and if so what would be reasonable CHT's on an o-320 E2G HC STC. I will have a freshly overhauled engine installed and don't want to cook it right out of the gate.

Second question: I know that I can set limits for CHT's EGT, shock cooling etc. If you have a similar engine and the UBG-16 can you share what values you are running for the alarms.
 
We have a UBG-16. I haven't heard of a significant difference in the temps the probes read vs. JPI. We had the fast response probes for a long time, but they were a little prone to failure after a few years, so we just switched to the slower-response probe.

We have the CHT alarms set for 390F. On really hot days it can be a struggle to keep our climb temps below this, so we sometimes need to tolerate a little time between 390 and 400. We don't use EGT alarms, but the EGT bar graph will tell you if something odd is going on. We also have OAT and Carb Temp added to the UBG-16. We have the carb temp alarm set at 35F, I think.

This is on a Continental O-470-50 (Pponk).
 
I have all positives to say about the UBG and EI. It’s a great budget engine monitor. I think the talk about differences in temp between JPI and EI is just that - talk. The only thing I knock it on is ability to export data. Yes, it’ll do it, but it’s cumbersome to the point of rarely wanting to bother. Up until a week ago I’ve never had a problem with the probes, but one just quasi-failed (it’s intermittent) on me after who knows how long, I bet 10-15 years or more. EI is a fantastic company to work with, even when they’re supporting product that I bought used, that they didn’t make a dime on. It’s not the sexiest monitor, but I definitely think it’s worth installing, especially if that helps you get to an IFR GPS.
 
AA5Bman said:
I have all positives to say about the UBG and EI. It’s a great budget engine monitor. I think the talk about differences in temp between JPI and EI is just that - talk. The only thing I knock it on is ability to export data. Yes, it’ll do it, but it’s cumbersome to the point of rarely wanting to bother. Up until a week ago I’ve never had a problem with the probes, but one just quasi-failed (it’s intermittent) on me after who knows how long, I bet 10-15 years or more. EI is a fantastic company to work with, even when they’re supporting product that I bought used, that they didn’t make a dime on. It’s not the sexiest monitor, but I definitely think it’s worth installing, especially if that helps you get to an IFR GPS.
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I would also agree with this. Besides having the UBG, I have FP5L in my Archer2. I had one problem on the EGT lead that turned out to be a crimping failure in the part of my installer. On another, the screen died out of warranty, but EI replaced the unit I think just for exchange.

Regarding alarms, I set my CHT to 380 which works for me. I think I set the EGT difference to 150 or 200 (what the EI manual suggested). This was fine until recently when #3 manifold was changed and the new location for the EGT probe, which appeared to be equal to the others was reading about 40 degrees hotter than in the past. This in turn made the EGT spread greater so my alarm goes on frequently. I have not yet bothered to reset since when operating at 65% or more, it stays within the preset limit.
 
AA5Bman said:
The only thing I knock it on is ability to export data. Yes, it’ll do it, but it’s cumbersome to the point of rarely wanting to bother.
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The EI rep has been hinting at a new data logger for these old legacy products for some time. Who knows - maybe we'll see something at OSH? Call me the eternal optimist.

C.
 
camorton said:
The EI rep has been hinting at a new data logger for these old legacy products for some time. Who knows - maybe we'll see something at OSH? Call me the eternal optimist.

C.
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That would be really helpful. I did get the serial to usb dongle installed with the UBG16 so I can at least hook up the laptop for now. My plane is several states away awaiting for final installation of engine (hopefully very soon) and after melting a piston in the middle of nowhere, I am looking forward to x-country flights without wondering what all of my cylinders are doing.
Once I download the data, is there software that is used to create the graphs are you just using the charting functions in Excell?
 
Yeah, I have an old, old Dell laptop with a DB9 serial port on the back that I keep around and its ONLY use is for downloading the UBG data. The battery is only good for about 30 minutes, and the screen is so dim I can barely read it, but it works! At this point, even the USB-A dongle is obsolete, right?

I upload the data to SavvyAnalysis (SavvyMX). They keep it all organized and have cool charting tools. They will also do diagnostics with the data if you have or suspect a problem - for a fee, of course. But just to upload and chart is free.

Seriously, if EI doesn't get on the stick and start selling something soon, I may finish up the one I was building and publish DIY plans. A serial data logger with an SD card slot can be had for $20? Just need to wrap up the software.

C.
 
camorton said:
Seriously, if EI doesn't get on the stick and start selling something soon, I may finish up the one I was building and publish DIY plans. A serial data logger with an SD card slot can be had for $20? Just need to wrap up the software.

C.
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I would be interested in that. Have you had success with your DYI unit yet?
 
Archimago said:
I have heard that the EI probes will read a little cooler then the JPI probes
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There are a series of easy tests one can perform to verify the accuracy of their temperature probes. First, does the instrument report ambient temps, or very close to before the engine is started? Second, the probe can be removed and submerged in an ice bath (70% ice/ 30% water). The instrument should indicate 32-33°F. Lastly and similar to the second test, submerge the probe in boiling water. The instrument should indicate roughly 212°F. These tests provide three known data points. If all provide the expected results, they are reporting accurately.

It is worth noting that EGT temperatures can differ among manufacturers, depending on the diameter of the probe, or the distance from the head that the probe is installed in the exhaust stack. What is important to remember regarding EGT is not the absolute temperature, but relative to peak. This is why no manufacture specifies and EGT redline. You may find one for a turbocharged aircraft, but that is typically TIT, not EGT.

Additionally, CHT probes will differ from a probe installed in the cylinder's threaded well, compared to a probe installed under a spark plug. The upper spark plug probe will typically show cooler temps due to engine baffling and a the lower spark plug probe will typically show hotter temps due to its proximity to the exhaust.
 
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Regarding an updated data logger for the UBG-16, probably not by OSH. But...probably not long after. No promises, though. ;)
 
The claim of different CHT readings with EI vs. JPI probes traces back (AFAIK) to a study done by Cubcrafters and published in July 2014. It is no longer at the link from which I got it, and being a copyrighted document I don't feel comfortable posting it here (sorry). I can, however describe what it says.

The study compared EI P-100 screw in probes, EI P-101 bayonet probes, JPI M-5050T probes, Dynon D180 probes and Alcor 86253 probes. They first compared the probes static readings in a heated oil bath (similar to the concept that Dave was suggesting). They found no differences between the probes. But when they installed them in an engine and flew, they saw differences.

They flew the same profile with each set of probes installed in the engine. For all but the Dynon probe they used and EI CGR30P as the recording instrument. The Dynon probe was no compatible with the CGR30P, so they read them with a Dynon D180 instrument. What they found was that the Dynon, Alcor, and JPI probes read about the same (within 10 degrees F). The EI P-100 probe read about 40-50 degrees F lower than that group, and the EI P-101 probes read intermediate between the higher temperature group and the P-100 probes (say about 20 degrees F lower than the higher temp group).

In summary, the P-100's read about 40-50F lower than the 3 non-EI probes, and the EI P-101 probes read about half way between the hotter group and the P-100 probes.

The next question is which readings are most comparable to the systems used to certify your engine. If they were grounded probes that contacted the cylinder head, then the hotter group should be the most comparable. If they were ungrounded and did not contact the cylinder head, then the P-100 probes would be most comparable. Unfortunately I was never able to find that out for my airplane.

Consequently with my Tiger's Lycoming O-360 with a CGR-30P and EI P-100 probes I look to keep my CHTs at or below about 385 F. That is about 45F lower than the 430F limit that Lycoming recommends for maximum engine life. Enough safety margin to compensate for a possible difference between my probes and the grounded/metal contacting probes that Lycoming might have used to set that temperature target. I've had no trouble keeping within that temperature limit, and the EI-100 probes have been rock solid in about 1000 hrs of operation. I've had some issues with the CGR-30P, but EI's tech service has been excellent.
 
bkspero said:
The claim of different CHT readings with EI vs. JPI probes traces back (AFAIK) to a study done by Cubcrafters and published in July 2014.....
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Thank you! I heard something similar on a list serv for Grummans but your explanation really helped me understand it. So if I keep it below 385 on break in. That would be the safest bet.
 
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