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EGT and CHT gauge

Posted: Wed Jun 24, 2015 8:18 pm
by tonyorlo
I building a turbo charged type 4, and I would like to watch all the temperatures as close as I can. I would like to monitor each cylinder for CHT, as well as EGT. Might be overkill, but this is my first air cooled engine and I don't want something to happen to it. As of now, I am going to use this,

http://thesensorconnection.com/gauges-p ... ge-display

but does any one have a better gauge to use? I like that one because I can see all the cylinders at once.

Re: EGT and CHT gauge

Posted: Thu Jun 25, 2015 7:49 am
by Steve Arndt

Re: EGT and CHT gauge

Posted: Thu Jun 25, 2015 5:21 pm
by tonyorlo
I couldn't find one on air craft spruce that was 8 channels. They all were very expensive too.

Re: EGT and CHT gauge

Posted: Thu Jun 25, 2015 5:53 pm
by Chip Birks

Re: EGT and CHT gauge

Posted: Thu Jun 25, 2015 6:14 pm
by Steve Arndt
Depends if you want PC display only, android display, logging, a dedicated dash display without a computer, etc. Lots of ways to go.

Re: EGT and CHT gauge

Posted: Thu Jun 25, 2015 7:43 pm
by tonyorlo
Sorry, I should of stated that. I want a dash display, something I can easily watch in real time. I'm not positive, but Id bet that I will need 1 CHT sensor for the megasquirt. The Can Egt could also be very helpful for data logging.

Re: EGT and CHT gauge

Posted: Thu Jun 25, 2015 8:59 pm
by Piledriver
There is an ongoing project for CAN-enabled gauge mechanisms at msextra.
(also a digital option)
Might be a good DIY thing, you could "CANify" some cheap gauges and stick whatever face/scale you like on them.
The clock in my T3 has never worked right for example, so it's a candidate.

http://www.msextra.com/forums/viewtopic ... 67&t=57948

All this assumes you have a Megasquirt or similar CAN speaking ECU.
(might work with ODB2 even with some code work)

Re: EGT and CHT gauge

Posted: Tue Nov 24, 2015 9:58 am
by tonyorlo
I just came across this,

http://www.aircraftextras.com/AG6T.htm

And this,

http://www.ultralightnews.ca/westach/318quad_gauges.htm

They both Would be good options if you wanted to monitor all 4 egts or chts.

Re: EGT and CHT gauge

Posted: Tue Nov 24, 2015 10:47 pm
by Piledriver
Slick.
I guess if you only want one idiot light, that top one rocks ;-)

The Westach cht/egt gauges are TC powered and not cold point compensated, so best used for EGT service where the reading being incorrect by 50-75 degrees is far less important than uniformity.

Re: EGT and CHT gauge

Posted: Wed Nov 25, 2015 12:46 am
by tonyorlo
Cold point compensated? I sound dumb, but I don't know what that means.

Re: EGT and CHT gauge

Posted: Wed Nov 25, 2015 1:20 am
by Piledriver
A typical digital TC setup will actually contain (effectively) two "thermometers": The one you hook up, and a reference in the TC amp chip.
That way it knows what temp the "cold" connections are (at the chip end)

This is due to the "secondary TCs" where the TC wires connect to the readout.

A TC powered gauge (non compensated/no TC amp) will be accurate if the gauge head is at (IIRC) 72F.
If where the gauge head is not 72F (or 68F or whatever the gauge was calibrated to) there will be a 1:1 offset in temp readout vs actual.

This means that if say the interior of your car is ~freezing, the CHT will read 40F off "correct", same issue in the opposite direction if your dashboard is for example at 112F. (I cannot recall which direction it goes out, but it depends on the gauge head temp)

For EGT the error is ~insigificant.

For CHT it can be the difference between keep driving or park it.

http://circuitcellar.com/cc-blog/the-ba ... mocouples/

Yes, you could figure out which way it is lying to you based on cabin temps and experience, but personally, any thermometer whose accuracy literally depends on the weather sucks and is not worth spending money on.

Re: EGT and CHT gauge

Posted: Sun Jan 31, 2016 9:27 pm
by fusername
EBAY has some cool aircraft stuff from time to time, I picked up one that just looked really cool but sadly only one of the channels worked so it's sitting in a box and occasionaly gets used to check out the boiler and stuff.

Re: EGT and CHT gauge

Posted: Sun Jan 31, 2016 10:55 pm
by Piledriver
Some of us might be able to fix stuff like that... :twisted:

Re: EGT and CHT gauge

Posted: Sat Feb 06, 2016 2:37 pm
by tonyorlo
Ive never really looked on ebay for one, Ill have to check it out.