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Ignition timing difference between AAN and ADU camshaft pulley

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  • Ignition timing difference between AAN and ADU camshaft pulley

    Hello,

    the camshaft pulleys between AAN and ADU engines are different. If we look at a engine which is turned to the top dead center of Cylinder 1, the positions of the AAN and ADU camshafts are different. That is why AAN camshafts shall be used with AAN pulleys and ADU camshafts with ADU pulleys.
    in addition the timing plate for the hall sender inside of the pulley is different. From looking at it (and asuming the camshaft pulley is rotating clockwise) the timing plate of the ADU pulley seams to reach the sensing element earlier then when using the AAN pulley.
    And here we come to my question: if I use ADU calibrated ignition timing maps with AAN camshafts and pulley, is the timing then overall shifted? (Because of the different hall sender plate inside of the pulley).
    And if the AAN pulley triggers the hall sender for ignition later, can I compensate that with a constant offset on the whole ignition map, let‘s say with +1,5° Ignition advance?

    My goal is to reuse a RS2 ignition map, but with using AAN camshaft and pulley.

    Best Regards,

    Daniel

  • #2
    I don’t know the workings of Motronic but I would guess timing is based on crank position reference and the cam sensor is just for sync / cycle reference.
    Panthero Coupé quattro 20vt
    Indigo ABY coupé
    Imola B6 S4 Avant

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    • #3
      Ahhh yes...I think you solved it. The hall sender is only there for the ECU to know when cylinder 1 is at the top dead center. For the ignittion timing there is G4 which triggers on the steel pin at the flywheel.
      Overall this would mean, there is no timing difference. X ° degrees of retard or advance in the ignitition map mean the same for aan or adu engine.

      edit: ssp says that hall sender and g4 are used for starting, but in fact g28 is used to count flyweel theeth between two ignitions. Now i‘m not so sure anymore...if they ECU takes the hall sender or G4 signal or both to say „here is 0°“
      Last edited by -ice-; 25 April 2019, 19:12.

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      • #4
        It would be poor practice to take timing reference from two places connected by a belt, since the belt will stretch meaning timing would drift with belt stretch.
        Therefore I expect all timing reference is done using sensors at the crank, cam sensor is there for cycle/phase sync reference. This explains why the G40 is only used at start.
        Panthero Coupé quattro 20vt
        Indigo ABY coupé
        Imola B6 S4 Avant

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        • #5
          Originally posted by Error404 View Post
          It would be poor practice to take timing reference from two places connected by a belt, since the belt will stretch meaning timing would drift with belt stretch.
          Therefore I expect all timing reference is done using sensors at the crank, cam sensor is there for cycle/phase sync reference. This explains why the G40 is only used at start.
          Nailed it. This thread is all about trying to run before one can walk. Basics first!
          http://tuner.ee - http://www.facebook.com/tuner.ee

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          • #6
            Thanks. Make sense to me to use the steel pin at the flywheel for ignition timing than the hall sender which is connected via a belt.

            Ignition timing is not linear over the rev range and of course also dependant on the cylinder filling. But I discovered that if offset the ADU ignition map with 1,5° advance my engine with AAN camshaft runs better (mainly in lower load areas) This is why I thought there might be a constant offset by system if using AAN camshaft and pulleyn compared to ADU parts.

            If it is there, it's then not coming from the hall sender plate...

            Best Regards

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            • #7
              For those with hall sensor on the cam pulley. The physical difference between ADU and others cam pulley is because ADU has special pulley on the water pump. With non-adjustable pulleys you must run ADU waterpump and cam pulley - or regular waterpump and regular cam pulley. You can use any cam shaft and any software with any engine. (or swap complete ADU head into AAN with AAN pulley, etc)

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              • #8
                The cam pulleys have these marks at the backside to find out the right position when installing the belt. I mean these small lines on two teeth which have to match the edge of the cylinder head and the arrow of the cylinderhead cover. And if you align them this way, the hall sender plate is positioned different between AAN and ADU. I don‘t understand why the waterpump makes a difference here...

                But I agree to you not to mix aan with adu parts concerning belt, pulley and waterpump. But even if you don‘t mix the hall sender plate position between aan and adu (if in default service position, that means cyl. 1 at top dead point) is slightly different. It seems not to desturb the ECU with identfying the actual cylinder.

                BR

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                • #9
                  The phase shift of the BM / TDC mark (caused by the VR sensor - higher voltage at higher engine speed) moves the ingnition a little bit. Everything else should be as demaded by the ignition maps.
                  The cam sensor could impact the injector beginning - didn't investigated this soo far.
                  ZW_OUT I already mentioned in another topic - there you could see the impact on the calculation and then you "only" need to check if the reference (TDC marking) is still valid

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