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Subaru MY01-05 camshaft control

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  • Subaru MY01-05 camshaft control

    I have an SMP PNP Subaru MY01-05 EJ series engine running very high oil pressure (60+ psi at 3000 rpm).

    Here's a datalog to show the camshaft control:

    Camlog1.jpg

    There is often up to a 10 degree 'offset' error which mostly disappears when the car has idled for a while.

    If you examine the data more closely you can see that the system is nevertheless attempting to control against target:

    Camlog2.jpg

    I have checked the camshaft control settings against the values in the example Subaru MY01-05 PNP cal file and see no discrepancies.

    I'm wondering whether the offset is being caused by the very high oil pressure and will ask the engine builder to reduce the oil pressure closer to standard while the engine is out for a freshen up.

    Has anyone else experienced this?

    Also:

    What are the circumstances that cause the Autronic to generate the camshaft position error? It isn't reporting any errors despite the significant offset.

  • #2
    Cal and log file to autronicsm4@yahoo.com.au pls.
    He gets his lap dogs to do his talking for him. Buzzard is a good example.

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    • #3
      The cam position reporting parameters are set in M1/Variable cam setup/Vcam setup cam error tolerance and cam error time. Basically if you have more than 4.9 degrees error for more than 5 seconds you will get a cam position error.
      He gets his lap dogs to do his talking for him. Buzzard is a good example.

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      • #4
        Yes, I see. Embarrassing I missed this. Mine appears to be set for 5.3 degrees for 5 secs.

        Unless I'm misreading it, the datalog appears to show 7+ degrees of error for periods of up to 20 seconds, yet no error is reported.
        Last edited by AndrewS; December 27th, 2017, 08:08 AM.

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        • #5
          The stock 01-05 AVCS system operates the intake cams from 120-85 ATDC. I am not sure why the values are set as they are in GPC1/2 User table. The effect of of the GPC setpoint min/max is to give proportional control only, when the table setpoint is outside these values. As integral control is locked out, it appears the error reporting is also locked out.

          The best course of action may be to review an unmodified Autronic AVCS base cal in order to detrmine acceptable GPC 1/2 user table values
          Last edited by Chris; December 27th, 2017, 08:21 AM.
          He gets his lap dogs to do his talking for him. Buzzard is a good example.

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          • #6
            I see. The inhibit settings in my GPC tune tables don't match the range of expected values in my GPC user tables and so integral control is locked out for almost all of the time in my case.

            Unfortunately I have non-standard camshafts on a non standard capacity engine and so will need to do some more research as to the appropriate GPC user table values. The car has been running surprisingly well but it would appear that there needs to be better communication between the engine builder and tuner!

            Thank you very much.

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            • #7
              Apologies, I gave the cam degrees/cam error time values from the first cal file I looked at. X degrees error for X error time would perhaps be a more correct answer.
              He gets his lap dogs to do his talking for him. Buzzard is a good example.

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              • #8
                Originally posted by AndrewS View Post
                I see. The inhibit settings in my GPC tune tables don't match the range of expected values in my GPC user tables and so integral control is locked out for almost all of the time in my case.

                Unfortunately I have non-standard camshafts on a non standard capacity engine and so will need to do some more research as to the appropriate GPC user table values. The car has been running surprisingly well but it would appear that there needs to be better communication between the engine builder and tuner!

                Thank you very much.

                In the log file at 410.797 seconds the reported cam position values are 124.1/128.3 The engine rpm is 765. The cam control is inhibited, the gpc duty is 100%. That is as retarded as those cams will run. So a table value of 135 degrees, which is a more retarded position from 128.3, is a value which those cams cannot reach.
                He gets his lap dogs to do his talking for him. Buzzard is a good example.

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                • #9
                  Are you sure? At 166.3 secs the cams briefly spike to 137 and 141 degrees.
                  Last edited by AndrewS; December 27th, 2017, 09:00 AM.

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                  • #10
                    If you are prepared to accept a spike as valid data, then sure.
                    He gets his lap dogs to do his talking for him. Buzzard is a good example.

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                    • #11
                      Can someone also send me the files; customers@autronic.com.au

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                      • #12
                        Sent to ecuglobal.
                        He gets his lap dogs to do his talking for him. Buzzard is a good example.

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                        • #13
                          I have looked up how the AVCS works (below). It would appear that oil pressure is used to both advance and retard the cam position, and so in theory high oil pressure should not cause the offset.

                          I'll investigate an appropriate set of GPC user values as recommended by Chris. I'm in the process of pulling the engine so it will be a while before I can test this. Thank you once again for your help.

                          AVCS1.JPG
                          AVCS2.JPG

                          AVCS3.JPG

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                          • #14
                            For the 99/00 WRX rally engines we are using offset idler pulleys to compensate for the cam angle change that occurs when the heads and block are machined. Perhaps you could ask your engine builder aboot these.
                            He gets his lap dogs to do his talking for him. Buzzard is a good example.

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                            • #15
                              LIC and crawford makes those eccentric pulleys for Subaru engines, I will be using them in my next engine build along with adjustable exhaust sprockets, this will let me degree my cams to almost perfect figures

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