EGT Sensor and GPIO + MS-II Question

For discussing how to choose sensors and create a wiring harness for all Bowling and Grippo versions of the MegaSquirt® EFI controller.
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Steph
MegaSquirt Newbie
Posts: 8
Joined: Fri Jun 24, 2011 5:12 am

EGT Sensor and GPIO + MS-II Question

Post by Steph »

Hey guys, can someone please tell me what I need to add an EGT sensor to my setup? I've search high and low, and maybe I missed something, but I'm confused as to whether I need to only buy the GPIO EGT package to use with the MS-II, or do I have to buy the full GPIO package with an EGT add-on? I already have the MS-II, and it seems extreme to add $250 to the price just to gain an EGT input to attach a sensor to. Am I missing something, aren't these just a high temp sensor?

Cheers,
Steph
Steph
MegaSquirt Newbie
Posts: 8
Joined: Fri Jun 24, 2011 5:12 am

Re: EGT Sensor and GPIO + MS-II Question

Post by Steph »

I should have stated I am about to buy the MS-II, not that I have it, and so it will have the latest code version and version V3.0 board. I just noticed above that this info is a requirement and must be included with such questions.

Steph
Matt Cramer
Super Squirter
Posts: 2951
Joined: Sat Jul 03, 2004 11:35 am

Re: EGT Sensor and GPIO + MS-II Question

Post by Matt Cramer »

That depends on how many EGT sensors you are wishing to add. If it's just one or two, you could build a circuit in the proto area and modify the INI files to log it. Current MS2 code does not use EGT for anything other than logging.
Steph
MegaSquirt Newbie
Posts: 8
Joined: Fri Jun 24, 2011 5:12 am

Re: EGT Sensor and GPIO + MS-II Question

Post by Steph »

Thanks Matt,

That's one less thing I need to worry about then. I figured it might have been useful, but I expect only in boost applications, which mine isn't.

Cheers,
Steph
Steph
MegaSquirt Newbie
Posts: 8
Joined: Fri Jun 24, 2011 5:12 am

Re: EGT Sensor and GPIO + MS-II Question

Post by Steph »

For anybody else that hits this thread in their searches, an EGT is pretty much an obsolete sensor with the advent of wideband oxygen sensors, with one exception. I found this on Wikipedia...
An exhaust gas temperature gauge (EGT gauge) is an automotive meter used to monitor the exhaust gas temperature of an internal combustion engine or rotary engine in conjunction with a thermocouple-type pyrometer. By monitoring EGT, the driver can get an idea of the car's air-fuel ratio. At a balanced air-fuel ratio, the exhaust gas temperature is lower than that in a lean or rich air-fuel ratio. High temperatures (typically above 1600 degrees F) can be an indicator of dangerous conditions that can lead to catastrophic engine failure.
This meter is most used in tuning turbo-equipped cars. If the sensor is installed at the manifold collector before the turbo, the turbine inlet temperature can be monitored. If the sensor is installed after the turbo, the exhaust temperature can be monitored. Because EGT will typically drop 200-300 degrees F across the turbine, installers in general will try to put the thermocouple as close to the cylinder head as possible to give a true reading that will require less mental math to read properly, and a reading that will react faster to the engine's condition compared to an installation after the turbo.
Using an EGT alone is considered an older technique for getting the most out of an engine, as a gauge-type wideband digital oxygen sensor can be purchased for about the same price, or for a little more. However, some advanced racers will use EGT gauges in combination with a wideband oxygen sensor to 'lean' the fuel ratio a bit to safely raise the temperature for more power.
Matt Cramer
Super Squirter
Posts: 2951
Joined: Sat Jul 03, 2004 11:35 am

Re: EGT Sensor and GPIO + MS-II Question

Post by Matt Cramer »

We generally use EGT for cylinder to cylinder tuning - eight thermocouples is a lot cheaper than eight widebands. We've never tuned a car using just one EGT probe.
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