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Installing IAT sensor post-IC ?


LGTspecB1657615261

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Are there sensors that are suitable for post IC measurement? Anyone have experience with this? Here is one on Ebay, but I would need to do some testing to correlate resistance to temperature unless they provide you with the output scale.

 

I want to find a cheap IAT sensor with a good response time... essentially a 2-wire thermocouple that is resistance based. I want to then hook it into a USB datalogger so I can get some data.

 

I am starting a new project and would like to log air temp just prior to the TB so I can measure efficiencies of the intercooler. Thanks.

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That's a rebadged GM open-element sensor. You can tell by the weatherpak style connector. They are commonly used in all sorts of aftermarket standalones like AEM EMS, Haltech, etc. http://forums.turbobricks.com/showthread.php?t=79740 has more info

 

http://www.fighters-garage.com/rx7.html another option is the Triumph open-element sensor: http://www.fighters-garage.com/pics/RIAT.jpg

 

this one uses a standard Bosch EV1 style fuel injector connector. The resistance levels are

 

@68 *F (20c) = 2.27 Ohms

@176*F (80c) = 0.34 Ohms

 

from what I've found. It is M10x1.25 thread. The Triumph sensor has a reputation for being very fast acting. I'm sure the GM one is at least close, because they are both open-element designs.

On the search for a new DD...
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Man you are awesome! Thanks, that is exactly what I was looking for.

 

I found one for $10 shipped! It does not have the connector, but I will just run some wires to it and protect the terminal. Hopefully I can find a second one and I can measure pre and post IC. Then I will create a small module with microcontroller and display that will scroll through the temps including a delta temp. This might also trigger some things ;).

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Trigger meth spray, for example? :)

 

I was going to suggest just getting a second stock MAF/IAT sensor and putting it post-IC. You could even feed the IAT signal right to the ECU if you want. I'm actually going to be relocating my MAF and IAT as soon as I can... still waiting on some parts.

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I might try to feed it right in, but I am not sure what the scale of the stock sensor is. I can always shift the signal of the GM sensor to match the Subaru sensor. I searched the manual and I see nothing about the OHM output scale of the factory IAT sensor. Sometimes they have the values in there for diagnosing issues, but I did not see it. I could always measure it and just log the values in RR - then figure out the correlation. I would have to drive in both hot and cold weather though, in order to determine the full scale.

 

My concern, though - doesn't the ECU use the air temp along side of the airflow sensor to calculate actual flow? i.e. doesn't it take the output of both signals and come up with airflow? If that is the case, it could be calculating airflow inaccurately because it is measuring temp in a different location than it is measuring flow.

 

Anyway, I just purchased a second sensor... so I will have two and I will be able to measure differential. The output temp really only means something if you know what the input temp is.

 

Oh, and its something much more fun than meth ;) Ok... well that is debatable.... but its not for a meth system.

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Going to reverse-engineer the compressor map by looking at flow, pressure, and temperature? That was on my mind for a while, still is...

 

You strike me as the kind of person who would enjoy RomRaider and a Tactrix OpenPort. For example, here's the intake air temperature sensor scaling from my car's ECU. Top row is volts, bottom row is IAT in Fahrenheit:

 

0.21    0.36    0.52    0.67    0.83    0.99    1.14    1.30    1.46    1.61    1.77    1.92    2.08    2.24    2.39    2.55    2.71    2.86    3.02    3.17    3.33    3.49    3.64    3.80    3.96    4.11    4.27    4.42    4.58    4.74
248.0    248.0    242.7    226.4    208.2    193.5    180.9    169.7    159.9    150.8    142.4    134.5    127.0    119.8    112.9    106.1    99.4    92.8    86.1    79.2    72.4    65.2    57.5    49.4    40.5    30.5    18.5    3.5    -19.9    -40.0

 

Those numbers don't line up real well, but if you copy-paste them into notepad and work on the spacing they'll make more sense.

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I never looked for that table... but I see that it is tucked under the Miscellaneous - Scalings folder. duh. Well that should be easy enough.... but I still think it is wrong to mess with the stock signal because it will screw up the calculations for airflow. perhaps.

 

I am just going to make something with some spare parts: microcontroller with inputs and a 4 digit display. A momentary button will scroll me through (1) IC inlet air temp, (2) IC outlet air temp, and (3) differential temp.

 

Once I get it working I will have to package it in something that looks decent and hide it somewhere in the cockpit :)

 

Yes, I enjoy RR and OpenECU stuff. Still learning. Right now I am trying to log on a MicroSD card. It will trigger whenever the coolant temp is over 170. Then I can just plug in the tactrix and it will log all of my driving onto a 2GB micro SD. That will really help get some data-points for CL tuning. Right now MikeyD is helping tune-in the Load Compensation table.

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It does not have the connector, but I will just run some wires to it and protect the terminal.

 

Don't do that just to save 8 dollars. Bring the sensor to carquest and ask them to find you a connector pigtail, they have a big book with all sorts of random crap (especially GM). With an actual connector it will be more secure and insulated from moisture.

 

http://www.legacygt.com/forums/attachment.php?attachmentid=75382&stc=1&d=1256941136

 

the blue insulator compresses against the plastic housing of the sensor to provide a weatherproof seal.

SP32-20091030-181832.jpg.ef195a1292774bbb50f6dde14340ed4a.jpg

On the search for a new DD...
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I got the sensors in and they came with connectors and the pigtail wires! What a deal! I got 2 of them for $19 shipped. Brand new.

 

I am not going to put the pre-IC in right away.... for now I am just going to log IAT from the MAF and post-IC air temp. It will at least tell me how close back to ambient I am getting.

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The new Taurus SHO, which is a twin turbo speed density (MAP-based) system, uses 3 IAT sensors and two MAP sensors to help measure efficiency of the intercooler. The IAT sensors are located in the airbox, post intercooler piping (combined with an integrated MAP sensor), and in the intake manifold (also combined with a MAP sensor).

 

http://www.legacygt.com/forums/attachment.php?attachmentid=75555&stc=1&d=1257223435

http://www.legacygt.com/forums/attachment.php?attachmentid=75556&stc=1&d=1257223435

http://www.legacygt.com/forums/attachment.php?attachmentid=75557&stc=1&d=1257223435

IAT_airbox.jpg.c15f412eb9438ed90e2f04dbb42c19a4.jpg

MAP_1.jpg.7366d66ed0ca68b1f69b9bc593ca7ccc.jpg

MAP_2.jpg.5f6b63d7290fbc4038dfc32e6dc5bb95.jpg

On the search for a new DD...
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  • 2 years later...

Anyone know of a 3-wire air temperature sensor? One that would work like a voltage divider: +5v, ground, and output.

 

I dream of wiring two of those up to my TGV sensor connectors.

But I don't even know if something suitable exists.

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  • 5 months later...

Bump, talked with Dom at Maxwell Power Services, will add this to the list of projects to tackle.

The PLX IAT module should output a 0-5v signal.

[CENTER][B][I] Front Limited Slip Racing Differentials for the 5EAT now available for $1895 shipped, please inquire for details! [/I][/B][/CENTER]
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Anyone know of a 3-wire air temperature sensor? One that would work like a voltage divider: +5v, ground, and output.

 

I dream of wiring two of those up to my TGV sensor connectors.

But I don't even know if something suitable exists.

 

National/TI LM20 + less than a buck in other parts to do some power conditioning.

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