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  • #16
    I remove the throttle body on WRX's and fit the IAT in the underside of the throttle body.
    I place it past the throttle blade towards the inlet manifold side.
    Makes for neat installation and the sensor cant be seen.

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    • #17
      Originally posted by waxdass View Post
      One thing that worries me is that engine heatsoak into the sensor itself, due to metal-metal contact. Thus causing higher than inlet air temperatures due to the hot engine. Does the sensor suffer in this way?
      No it doesn't suffer much from conducted heat. It is infact rather good isolated from the heat in the pipe.
      Contrary to most other type of IAT sensors on the market.
      Johan Jansson, +46-708-280832

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      • #18
        Originally posted by supercharged88 View Post
        I remove the throttle body on WRX's and fit the IAT in the underside of the throttle body.
        I place it past the throttle blade towards the inlet manifold side.
        Makes for neat installation and the sensor cant be seen.
        hey mate, do you have a picture or something to show this?
        Are you still drilling into the manifold or just the throttle body itself?

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        • #19
          Sorry i never bothered taking photos of this when i have done it.
          I drill into the throttle body itself, on the underside.
          I drill the hole past the lip where the TMIC hose stops on the throttle body.
          Make sure that you place the hole correctly.
          You do not want to have the IAT sensor fouling the throttle blade.

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          • #20
            OK, i have been made aware that 01+ JDM WRX STi's come with a IAT sensor under the throttle body (measuring manifold temp).
            Supercharged88 - I think we might be talking about the same thing.
            I am going to see my tuner tomorrow, and check If the Aus ones are lucky enough to have this included aswell. fingers crossed! will save me drilling.

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            • #21
              Originally posted by waxdass View Post
              OK, i have been made aware that 01+ JDM WRX STi's come with a IAT sensor under the throttle body (measuring manifold temp).
              Not on the DOHC turbo engine. I haven't seen one on any JDM or other market STI turbo engine at least.
              But on the non turbo SOHC there seems to be one according to the workshop manual.
              Johan Jansson, +46-708-280832

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              • #22
                Originally posted by Wroom View Post
                Not on the DOHC turbo engine. I haven't seen one on any JDM or other market STI turbo engine at least.
                But on the non turbo SOHC there seems to be one according to the workshop manual.

                Actually, I can confirm that there is a IAT sensor for the manifold on JDM Spec C WRX STi and some S series cars, for homologation purposes.
                However - ADM STi's seems a bit of hit and miss...

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                • #23
                  Originally posted by waxdass View Post
                  Actually, I can confirm that there is a IAT sensor for the manifold on JDM Spec C WRX STi and some S series cars, for homologation purposes.
                  However - ADM STi's seems a bit of hit and miss...
                  So there is one model turbo that got one? Wow.
                  I shouldn't be amazed by that, since i know there is a lot of variety on models sold on different markets, as well as big differences in wiring from year to year. Sometimes with no obvious reason.
                  Homologation of parts is though as good a reason as any.
                  Johan Jansson, +46-708-280832

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                  • #24
                    Originally posted by waxdass View Post
                    OK, i have been made aware that 01+ JDM WRX STi's come with a IAT sensor under the throttle body (measuring manifold temp).
                    Supercharged88 - I think we might be talking about the same thing.
                    I am going to see my tuner tomorrow, and check If the Aus ones are lucky enough to have this included aswell. fingers crossed! will save me drilling.
                    I have never seen a WRX with an IAT sensor fitted in this location other than when i fit them there.
                    So i have always had to drill and tap the thread myself.
                    Does this sensor you are talking about use a 1/8 npt thread.

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                    • #25
                      Originally posted by supercharged88 View Post
                      I have never seen a WRX with an IAT sensor fitted in this location other than when i fit them there.
                      So i have always had to drill and tap the thread myself.
                      Does this sensor you are talking about use a 1/8 npt thread.
                      Its hard to come by unless you have spec c manifold.
                      I dont know what thread type the stock ones are - I'v had it confirmed by 2 tuners in Oz, that build subaru rally cars.

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                      • #26
                        Some STi's most certainly came with an air temp sensor. I worked on one that was used for Group N rally, I believe it was originally a JDM car (RHD). If it does have one it will be under the throttle body. I have attached pics at the bottom of this post. Also, if you are lucky enough to have one, chances are that pin D14 in the 31 pin ECU connector will be the siganl output. If memory serves me correct B27 in the 28 pin connector is the signal from the MAF's air temp sensor, so simply remove B27, and replace it with D14, and set the air temp sensor type to NTC.



                        You can see it under the throttle body in this pic.

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                        • #27
                          JDM STI's from 2003 have the manifold air temp sensor fitted for Group N homologtion. Spec C's might have had them bit earlier as Waxdass noted. Also from 2005 the JDM STI's had a higher pressure MAP sensor with the recessed top which you can see in hioctane's picture.

                          The high pressure MAP sensor reads to 1.8 bar of boost (compared to 1.53 bar for the standard sensor). However, 2.5L engines with the recess in the sensor are not high pressure so you have to check the part number to make sure you have the sensor you want.

                          On a WRX PnP ECU the extra air temp sensor can be selected with jumper links JP14 1&2 so it is not necessary to swap any wires in the original loom.

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                          • #28
                            Look at the attached picture from a log of a 555 grpn rally car on a long stretch on gravel.
                            A much tougher fight to keep grip and keeping the temperatures down than for a street car.

                            The turbo is fighting the restrictor with the wastegate fully shut, and the boost is responding to grip.

                            Please note the intake temperature rise from 53.2 to 99.9 Celsius on this long stretch in a stint.
                            This is with the biggest homologated TMIC for the Impreza.

                            Since this is how it actually can look, i certainly recommend using the Autronics MAP and IAT sensors simply because of their accuracy and quick response.
                            Attached Files
                            Johan Jansson, +46-708-280832

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                            • #29
                              OK so I have taken the throttle body off, and looked around.

                              My car unfortunatly does not have a factory IAT sensor, however I think I have spotted the area (bung) where it is placed.

                              You can see right down the bottom of the manifold there is a clear spot - with a hole that diagonally angles into the manifold.
                              The bad thing about this is - I think I'm going to have to completely remove the manifold in order to be able to drill the hole further.

                              Any opinions?

                              Without throttle body :



                              with throttle body:




                              For reference below is a Spec C manifold. You can see that there is an extra hole at the bottem (and the space is not on a angle like mine) - where the factory IAT sensor is placed.
                              Last edited by waxdass; February 16th, 2009, 01:30 PM.

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                              • #30
                                RE the LOG trace;

                                If that is Group N then don't take the car to Technical Control, the restrictor has fallen out of the turbo. Also, the last time I looked at Group N regulations, the original sensors have to be used for the engine operation.

                                But technically that log shows a very badly located MAP signal (up to 25kpa scatter most likely from an intake runner fitting instead of the plenum). And the only time I have seen air temperatures like that recently on a rally Subaru were with a light pod fitted. The light pod interrupted the air flow to the bonnet scoop so much that the waterspray water was sucked out. The engine didn't last long with the light pod fitted, and the light pod didn't last long after the log was reviewed (112 deg air temp, somewhat higher than it had been dynoed to).

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