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Interest in a “plug and play” EGT probe kit?

Old 11-12-2006, 09:46 AM
  #46  
Mike1982
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Yea, that would be interesting for data logging... Does the SMT-6 support it or at least an input to it?
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Old 11-12-2006, 02:40 PM
  #47  
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Graham and “Mike 1982”

Similar to 99% of automotive EGT probes it internally is a K-type thermocouple and as such only produces only 36 mV (.036 V) at 1600 F and 0 mV at ambient.
So if your datalogger is digital its ability to pick up the signal depends on its input bit count (A/D converter bit count). Assuming your input range is 0-5V then a 6, 8, 10 or 12 bit converter will give you 76 mV, 20 mV, 5 mV or 1 mV reading quantization. In other words 12 bits or better appear to be necessary for direct reading.

In any case my probe supplier is looking into finding an EGT probe amplifier and I’ll update you here when/if he finds some.
If anybody else know of such an amplifier please let me know. I want one or two for my TEC-3 managed Jalpa too.

Here are some temperature to millivolt (mV) conversion tables for K-type thermocouples: Fº to mV and Cº to mV

Laust
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Old 11-12-2006, 03:35 PM
  #48  
Tom M'Guinn
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Originally Posted by Laust Pedersen
In any case my probe supplier is looking into finding an EGT probe amplifier and I’ll update you here when/if he finds some.
If anybody else know of such an amplifier please let me know. I want one or two for my TEC-3 managed Jalpa too.



Laust
They're out there. All google, but see, e.g.,

http://www.mpsracing.com/products/RPM/datalogger.asp
http://www.racingconverters.com/sensors.html
http://www.performancetrends.com/The...e_Recorder.htm
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Old 11-23-2006, 03:05 AM
  #49  
Laust Pedersen
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I had a chance to install an EGT sensor in the X-over pipe and collect some comparative data from that and cylinder #2 sensor mounted near the exhaust ports. The results are as follows:

1. The graph in the picture shows the cold engine at idle.
2. Idle hot: TX: 950 ºF and T#2: 1140 ºF
3. No load (standing still) @ 3000 rpm: TX: 1200 ºF and T#2: 1420 ºF
4. 4th gear cruising at 45 mph (~14in hg vacuum): TX: 1220 ºF and T#2: 1320 ºF
5. 5th gear cruising at 70 mph (~12in hg vacuum): TX: 1400 ºF and T#2: 1400 ºF
6. 5th gear at 70 mph under load, hill (~0 psi boost): TX: 1520 ºF and T#2: 1420 ºF
7. 5th gear at 80 mph under load, hill (~0 psi boost): TX: 1650 ºF and T#2: 1550 ºF

Where TX and T#2 are the temperatures in the test fitting of the X-over pipe and header close to exhaust port #2.
The measurement reading accuracy is ±10 ºF and the 3 cylinders I still had probes in were never more than 30 ºF different from each other.

On my car there are a few OEM deviations relevant for these measurements, namely thermally coated headers (Jet Hot) inside and out and a missing aluminum belly pan.

In other words the location of the EGT probe for finding the exhaust gas temperature is not critical for a hot engine once the exhaust flow exceeds 5th gear cruising at 70 mph. However the gas temperature after the header can actually be slightly higher that at the cylinder head port under load and the response time is slower maybe by a factor of 2.


Laust
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Last edited by Laust Pedersen; 11-25-2006 at 02:38 PM.
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Old 11-23-2006, 07:27 AM
  #50  
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Great data Laust. The confirms my belief that during full throttle logging the numbers are the same.

Something that is important, and good, to remember is that the probe in the cross-over isn't just installed further down the stream from the first probe - it's measures the temp of the exhaust from all the cylinders. The exhaust comes in pulses from each combustion stroke from each cylinder and when these pulses are merged the heat goes up.

Last edited by Duke; 11-23-2006 at 08:53 AM.
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Old 11-23-2006, 08:06 AM
  #51  
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hey laust, how did you get a graph like that? did you have the info and make it yourself or is it parrt of your logger?
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Old 11-23-2006, 08:47 AM
  #52  
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it looks like ms excel to me .
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Old 11-23-2006, 02:09 PM
  #53  
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Originally Posted by facboy
it looks like ms excel to me .
Yes it is. Sort of “old school science project”: Read the instrument(s), write on paper, transfer to graphing software (Excel) and take a picture of computer screen (I don’t know how to directly upload Excel data or graphs).

.

Last edited by Laust Pedersen; 11-25-2006 at 02:44 PM.
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Old 11-23-2006, 06:55 PM
  #54  
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so it looks like if you added ~350 deg to the xover temp it should be pretty close to the #2 runner
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Old 11-25-2006, 02:44 PM
  #55  
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Originally Posted by TRP951
so it looks like if you added ~350 deg to the xover temp it should be pretty close to the #2 runner.
That may be true for the graph, but that is only valid for a cold engine in the process of warming up. Please read my post #49 a little closer.



Originally Posted by Duke
Great data Laust. The confirms my belief that during full throttle logging the numbers are the same.

Something that is important, and good, to remember is that the probe in the cross-over isn't just installed further down the stream from the first probe - it's measures the temp of the exhaust from all the cylinders. The exhaust comes in pulses from each combustion stroke from each cylinder and when these pulses are merged the heat goes up.
Your statement must be more than a “wild guess”.
Driving to San Diego (and back) I noticed that the X-over temperature crept above 1600 ºF on long hills, something I have not see with port measurement, so I took a note of the temperatures and sure enough the gas in the X-over pipe in some cases were 100 ºF above the port temperature.
In order to keep the data concentrated in one place, I edited post #49 to include the new measurements.

Laust
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Old 11-26-2006, 08:25 AM
  #56  
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Originally Posted by Laust Pedersen
Yes it is. Sort of “old school science project”: Read the instrument(s), write on paper, transfer to graphing software (Excel) and take a picture of computer screen (I don’t know how to directly upload Excel data or graphs).

.
if you want to just show charts or whatever, you can just hit alt-printscreen (on windows). this will screen capture the current window to the clipboard, and then you can paste it into any image program and save it (ms photo editor that comes with office will work). the raw screen cap will be pretty big, but you can convert it to jpeg or gif to make it smaller (charts/data should save pretty small as a gif image).
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Old 11-26-2006, 05:26 PM
  #57  
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Originally Posted by Laust Pedersen
Your statement must be more than a “wild guess”.
Yes indeed
But I have to be careful here, everyone seems so convinced that 1" from the port is the hottest and therefore best location


BTW, does someone know of a gauge/controller than can output a 0-5v signal from the EGT?
My PLX R-500 can, but that one is going in the green car for a fixed installation, I need something for my portable box (already has datalogging for rpm, a/r and boost).
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Old 12-02-2006, 10:44 PM
  #58  
Laust Pedersen
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Default One batch of P&P EGT kits done

I finally finished the first batch of the EGT P&P kits and have contacted (almost) everybody who showed interest.

Please let me know if somebody feels overlooked or if you now are interested. I did make a few more than the immediate interest could justify.



Originally Posted by rcatherton
Please count me in.
rcatherton, I have no way of contacting you without your PM enabled.

Laust
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Old 12-04-2006, 09:59 PM
  #59  
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Laust,

PM Enabled.

Thank You,

Richard
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Old 12-04-2006, 10:05 PM
  #60  
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PM'ed


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