Cylinder Head Temps, My Experience + lessons learned Options

[rwilner]

The criteria which make a gauge useful in an aircraft are different from an automobile.

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In an airplane you're often staring at your instruments as your primary information source, so dense displays with complex information are ok. In a car, as Chris points out, a quick glance at the instrument needs to give you the info you need.

"Staring at your instruments"??

Well, if you're IFR, anyway.

[McMark]

I like It's got 4 CHT + oil pressure + oil temp + other features.

The MGL instruments are interesting. I'd like to see one in use to compare it to the ones we've been selling. There are a lot of factors I consider when choosing cockpit instruments, especially how quickly I can get the information I'm looking for without being distracted from the road.
The criteria which make a gauge useful in an aircraft are different from an automobile.

I have one in a customer car. He loves it. Because the CHT is a bar graph, you can see and compare all four values in an instant, once you're used to what 'normal' looks like.

[falconfp2001]

I like It's got 4 CHT + oil pressure + oil temp + other features.

The MGL instruments are interesting. I'd like to see one in use to compare it to the ones we've been selling. There are a lot of factors I consider when choosing cockpit instruments, especially how quickly I can get the information I'm looking for without being distracted from the road.
The criteria which make a gauge useful in an aircraft are different from an automobile.

I have one in a customer car. He loves it. Because the CHT is a bar graph, you can see and compare all four values in an instant, once you're used to what 'normal' looks like.

that would be nice having a bare graph to compare all four cylinders. Does it flash the graph at a set high temp? That would be the best option on Chris's Gauge, showing the hottest cylinder at all times.

[ww914]

Rich

The Westach CHT KIT that I saw was a total of $218 for guage, switch and four probes. I called A/S to make sure.

Everyone makes good points about the different needs in an auto as opposed to an airplane. I guess it's just about what convenience you are willing to pay for. In my case, I have gone from thinking about no guage, to one gauge and one probe, to four probes, a switch and one guage, to possibly one guage with all readings nearly simultaneous. All this on a street car. Where do you stop? Back to the drawing board, I guess.

One other point, if someone knows anything about the Westach units, please speak up. I would hate to buy crap and then have to start all over again.

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[jsayre914]

I am learning sooo much from this thread. I have decided one more guage cant hurt (IMG:style_emoticons/default/rolleyes.gif)

While looking at all the 4 channel guages, i found that I really like the idea of seeing all four at the same time and the

MGL AVIONICS TC-2 THERMOCOUPLE TEMPERATURE DISPLAY Guage

seems to be the perfect one, you dont have to view it as a bar graph, if I am understanding the manual, you can read all four as a digital display at the exact same time in real time. look at the last pic of the guage. That is just cool (IMG:style_emoticons/default/beerchug.gif)

[falconfp2001]

I am learning sooo much from this thread. I have decided one more guage cant hurt (IMG:style_emoticons/default/rolleyes.gif)

While looking at all the 4 channel guages, i found that I really like the idea of seeing all four at the same time and the

MGL AVIONICS TC-2 THERMOCOUPLE TEMPERATURE DISPLAY Guage

seems to be the perfect one, you dont have to view it as a bar graph, if I am understanding the manual, you can read all four as a digital display at the exact same time in real time. look at the last pic of the guage. That is just cool (IMG:style_emoticons/default/beerchug.gif)

(IMG:style_emoticons/default/agree.gif) Very Nice. Besides being able to monitor CHT on all for cylinders, does MS have the ability to tune to four CHT inputs?

Maybe MS 3?

[Rand]

Any chance this view will automatically switch the channel reading across the top to show just the hottest cylinder? I would love that, best of both: One number reading for hottest temp, and bar graph for quick visual comparison of differences.

[biosurfer1]

Any chance this view will automatically switch the channel reading across the top to show just the hottest cylinder? I would love that, best of both: One number reading for hottest temp, and bar graph for quick visual comparison of differences.

According to the manual, yes you can. The value across the top can either be the highest current value, or a scanning value. It can also store the highest readings for each cylinder in built in flash drive for retrieval later, not to mention you can set alarm levels for each cylinder.

[Rand]

Very cool! Thanks Brett. I would definitely set the alarm too.

[jsayre914]

I called Dave @ Aircraftspruce, and told him we may need a few of these (IMG:style_emoticons/default/biggrin.gif) I also told him about 914world and that we would like special pricing because it makes us feel special. He is going to get me a price on 10 of them, if its worth it I will report back to you guys tommorow.

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[jsayre914]

I forgot we need sensors too, so I called Harold @ The Sensor Connection and told him we need a quote on at least 40 CHT sensors 14mm and he also said no problem, he will get back with me tommorow, he also said he was just about to pick up the MGL guages himself, and he will beat whatever price aircraftspruce will quote me on 10pcs....

this is getting interesting....

(IMG:style_emoticons/default/chowtime.gif)

i think i smell a group buy starting tommorow (IMG:style_emoticons/default/biggrin.gif)

[ww914]

Funny how these things work. Good job Joseph.

[falconfp2001]

I forgot we need sensors too, so I called Harold @ The Sensor Connection and told him we need a quote on at least 40 CHT sensors 14mm and he also said no problem, he will get back with me tommorow, he also said he was just about to pick up the MGL guages himself, and he will beat whatever price aircraftspruce will quote me on 10pcs....

this is getting interesting....

(IMG:style_emoticons/default/chowtime.gif)

i think i smell a group buy starting tommorow (IMG:style_emoticons/default/biggrin.gif)

(IMG:style_emoticons/default/w00t.gif) OK, if you can get this down to about 370 or lower then I think it is a go for a group buy. All vendors welcome to make other offers as I think this has a lot of interest and potential.

[falconfp2001]

I forgot we need sensors too, so I called Harold @ The Sensor Connection and told him we need a quote on at least 40 CHT sensors 14mm and he also said no problem, he will get back with me tommorow, he also said he was just about to pick up the MGL guages himself, and he will beat whatever price aircraftspruce will quote me on 10pcs....

this is getting interesting....

(IMG:style_emoticons/default/chowtime.gif)

i think i smell a group buy starting tommorow (IMG:style_emoticons/default/biggrin.gif)

(IMG:style_emoticons/default/w00t.gif) OK, if you can get this down to about 370 or lower then I think it is a go for a group buy. All vendors welcome to make other offers as I think this has a lot of interest and potential.

BTW, awesome work on the phone.

[ChrisFoley]

Apart from finding a good location for the large format of the TC-2 instrument it appears to be an excellent choice.
The user selectable multiple configuration display is a huge step forward from previously available cockpit gauges.
Heck, I'll buy one if the price is under $400 delivered.
I don't have enough margin on the units I've been selling to offer any discount.

[rwilner]

(IMG:style_emoticons/default/agree.gif) Very Nice. Besides being able to monitor CHT on all for cylinders, does MS have the ability to tune to four CHT inputs?

Maybe MS 3?

Out of the box, Micro/Megasquirt, like most EFI systems, performs the fuel injection calculation based on a single engine temperature input. For water cooled engines, it's coolant temp; for air cooled engines, it's cyl head temp. There may be other temp sensors, like an air temp sensor, that go into the injection calculation as well...but there is only one *engine* temp input.

It doesn't matter where (within reason) you're measuring engine temp for this calculation as long as you tune the fuel map to the location at which you're measuring. However, for *monitoring the health* of the engine, you need to measure at the hottest spots...under the spark plug.

I suppose if you were running sequential (not wasted) spark, sequential (not batch) injection, and had individual CHT and/or AFR and/or EGT sensors for each cylinder, you could somehow adjust the mixture for each cylinder. No EMS system that I know of supports this out of the box; however, I guarantee you that you could make a system that would do it. Some combination of MS3 and MSExtra components may get you there.

Unless you are planning to run the engine at 99% of its performance envelope for an extended period of time (a purpose-built motor to set a land speed record or something), this level of cost, control, and complication seems excessive. But, it would be wicked fun to try and build it!!

As far as the group buy...I'm in given my recent experience...although the thought of ripping my interior apart AGAIN to run MORE wires makes me sad. (IMG:style_emoticons/default/wink.gif)

[rwilner]

Rich

The Westach CHT KIT that I saw was a total of $218 for guage, switch and four probes. I called A/S to make sure.

Warren
You're right. Because they list the prices for each component separately, I thought you had to purchase everything separately. My mistake!

[rwilner]

I forgot we need sensors too, so I called Harold @ The Sensor Connection and told him we need a quote on at least 40 CHT sensors 14mm and he also said no problem, he will get back with me tommorow, he also said he was just about to pick up the MGL guages himself, and he will beat whatever price aircraftspruce will quote me on 10pcs....

this is getting interesting....

(IMG:style_emoticons/default/chowtime.gif)

i think i smell a group buy starting tommorow (IMG:style_emoticons/default/biggrin.gif)

(IMG:style_emoticons/default/w00t.gif) OK, if you can get this down to about 370 or lower then I think it is a go for a group buy. All vendors welcome to make other offers as I think this has a lot of interest and potential.

Don't forget we're going to need about 40' of K-type TC wire as well (purple jacket). A complete kit would include the wire, gauge, sensors, and enough terminals / splices to get the job done.

And oh yeah, probably 3 beers.

[ChrisFoley]

Don't forget we're going to need about 40' of K-type TC wire as well (purple jacket). A complete kit would include the wire, gauge, sensors, and enough terminals / splices to get the job done.

And oh yeah, probably 3 beers.

Any connections added to the thermocouple wires may mean the cold junction compensation feature of the instrument won't work. FYI

My 4 channel instrument comes with extended wires on the gauge, so no need for extra wire, but it has no built-in cold junction compensation. If you understand what that compensation does its a minor feature anyway. I put the connectors inside the cockpit where the temp is most stable and closest to the ideal 75F to minimize any inaccuracies.

[rwilner]

Don't forget we're going to need about 40' of K-type TC wire as well (purple jacket). A complete kit would include the wire, gauge, sensors, and enough terminals / splices to get the job done.

And oh yeah, probably 3 beers.

Any connections added to the thermocouple wires may mean the cold junction compensation feature of the instrument won't work. FYI

Chris
My understanding is that the compensation feature will work correctly if the splices for all 4 TC channels are at the same temperature (i.e. in the same location).