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  • #16
    So here is a comparison for anyone interested before and after the Vanos replacement. The recent run was with a tank of 95 petrol as I forgot I was getting the car dyno'd and was being cheap. I'll be back with a tank of 98 to see if it makes much difference to the results, however you can see the torque is improved massively across the entire rev range.

    The car is an E36 M3 Evo totally stock.

    Wheel HP and Torque
    Now: Running on 95Ron


    Before vanos fix: Running on 98+ Ron



    Flywheel HP and Torque
    Wheel HP and Torque
    Now: Running on 95Ron


    Before vanos fix Running on 98+ Ron



    Flywheel HP and AFR
    Now: Running on 95Ron


    Before vanos fix Running on 98+ Ron
    Ex 2001 S54
    New cars:
    Lotus Carlton
    350Z

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    • #17
      Makes a big difference then!

      Are there any tell tale signs that the vanos is on the way out before the noise comes? My engine can be ticky but on the rhs of the engine bay, not near the vanos. What are the key maintenance jobs on it? Sure this has been covered elsewhere but I'm being lazy, and since mine is the only car I've been in I have no comparator

      Build thread: https://www.z3mcoupe.com/forum/showthread.php?t=19347

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      • #18
        Originally posted by Dave P View Post
        My car pulls through the rev range without big steps at certain revs - I thought this was how the S50 engine runs?
        Same here now with a new factory serviced Rolls Royce vanos unit. No noticeable steps, smooth power from idle to redline.

        The original was not any more capable to adjust the cams smoothly and continuously due to leaking piston seals. There was not enough oil pressure to move the cams smoothly at low revs and thus the old one adjusted the cams more abruptly.
        The older I get, the faster I was ...
        BMW HP2 Sport
        ex- BMW Z3 M Coupe - Cosmosschwartz Metallic

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        • #19
          Originally posted by mnbrennan View Post
          Are there any tell tale signs that the vanos is on the way out before the noise comes?
          The vanos may be somewhat noisy and the seals might still be ok or vice versa.
          After replacing the vanos myself and taking a detailed look into it, I will no more be worrying about some noise if vanos otherwise works ok.

          For me, the most prominent tell tale sign was somewhat uneven idle especially during the first 5 seconds after starting. The engine also idled for some time over 1100-1300 rpm before dropping to normal 700-800 rpm.

          Another thing was that when turning the front wheels when the car was not moving, the power extracted by the power steering caused the idle to raise up to 900 rpm. The effect was worse if AC was on. Then idle might jump up to 1100-1200 when turning wheels without rolling.

          After vanos change, idle is steady and drops to 700 rpm very quickly after a cold start. No "blop" sounds from exhaust, just a steady and healthy humming.

          AC I have not yet been able to fully test due to obvious reasons :
          https://v2tre.wordpress.com/2015/01/24/lumikissa/
          The older I get, the faster I was ...
          BMW HP2 Sport
          ex- BMW Z3 M Coupe - Cosmosschwartz Metallic

          Comment


          • #20
            Originally posted by MGR View Post
            So here is a comparison for anyone interested before and after the Vanos replacement. The recent run was with a tank of 95 petrol as I forgot I was getting the car dyno'd and was being cheap. I'll be back with a tank of 98 to see if it makes much difference to the results, however you can see the torque is improved massively across the entire rev range.
            Easy to believe that effect of healthy vanos into the torque. I have been smiling every time riding the Z3M after the vanos fix.

            The difference between RON 95 and RON 98 is really surprisingly large !
            I have always used 98 so have not been able to notice that in practise but that large difference would be easy to feel. Will keep using 98 !
            The older I get, the faster I was ...
            BMW HP2 Sport
            ex- BMW Z3 M Coupe - Cosmosschwartz Metallic

            Comment


            • #21
              Originally posted by MGR View Post
              Just to add to the confusion, I've just had the Vanos replaced on my E36. Oddly the step between 'stages' was more obvious when it was not working properly, its now a lot smoother and making ~25 bhp more than it was pre Vanos fix.

              To drive it feels like it has more torque down low (which it does) and is smoother in the transition around the 2500 rpm mark.
              Who did you use to replace your vanos?

              Comment


              • #22
                Originally posted by Dave P View Post
                Who did you use to replace your vanos?
                I used Mr Vanos.
                Ex 2001 S54
                New cars:
                Lotus Carlton
                350Z

                Comment


                • #23
                  Originally posted by MGR View Post
                  I used Mr Vanos.
                  nice one

                  Comment


                  • #24
                    I had the same symptoms in my car (S54). Felt like it had a flat spot low down and suddenly started pulling like a train from 3000-3500rpm. And when I say flat spot, from a standing start a VW Polo would pull away from me.

                    Then a day on it started idling rough, like a V8 that had its cams done. The car had a new VANOS fitted by BMW just over a year ago (not even 2000 miles done since), so I was fairly certain that it's not a mechanical issue. Ended up tracing it back to the engine wiring loom.

                    Two of the wires connected to the Vanos solenoid connector / plug were damaged. Also, the rubber seal inside the connecter was split and I suspect contact was a bit iffy because I really struggled to get the old plug back onto the solenoid. I replaced the plug and fixed the wiring and all is well.

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