Transmission ratios

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  • twnygren
    Noobie
    • Jan 2010
    • 9

    #1

    Transmission ratios

    I was wondering if the getrag 260 in the m42 318is, and the getrag 260 in the 325i have the same gear ratios. I have a 318is now, and I was wondering if a 325i with a 4.10 differential would be similar. I mean IIRC when crusing in my 318is at about 70 on the highway, in 5th, my tach reads a little over 3k. Would a 325i with a 4.10 diff be at about the same rpms at 70?
  • Wh33lhop
    R3V OG
    • Feb 2009
    • 11705

    #2
    The 318i has a getrag 240, not a 260. You've got a 4.10 and a .83 5th gear as opposed to the 325i's 3.73 and .81 fifth gear, so you'll be turning over a tad more rpms than a 325i with a 4.10.

    On the bright side, the G240 has slightly closer ratios.
    paint sucks

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    • twnygren
      Noobie
      • Jan 2010
      • 9

      #3
      I though that the m42's had a 260 in them, and the m10's had a 240.

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      • Wh33lhop
        R3V OG
        • Feb 2009
        • 11705

        #4
        Originally posted by twnygren
        I though that the m42's had a 260 in them, and the m10's had a 240.
        I've been wrong before.
        paint sucks

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        • nando
          Moderator
          • Nov 2003
          • 34827

          #5
          Originally posted by twnygren
          I though that the m42's had a 260 in them, and the m10's had a 240.
          nope they both have a 240 although the bellhousings are different.
          Build thread

          Bimmerlabs

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          • twnygren
            Noobie
            • Jan 2010
            • 9

            #6
            Okay, thanks for the help. I have another question, the speedometer sensor is in the differential, not the transmission, correct? So you can change a diff without having to recalibrate the speedometer?

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            • nando
              Moderator
              • Nov 2003
              • 34827

              #7
              it's in the diff, and no you don't have to calibrate the sensor. all BMW diffs use the same speedometer wheel/sensor.
              Build thread

              Bimmerlabs

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