m46 or 3.54 rearaxis

Discussion in 'General Motoring' started by kwijlebabulus, Aug 21, 2004.

  1. Hello

    'Cause I'm driving a lot of highway, I would like to decrease my rounds
    par minutes.

    I'm driving a B230 engine with a m47 (5speed) and a 3.73 rear axis.

    Now I was wondering what I should change to decrease my RPM.

    Take an m46 with OD and my old 3.73 rear axis
    or
    keep my m47 and take the 3.54 rear axis.

    (or take the m46 and the 3.54)

    Do you folks have an idea or opinion about this?

    All advices and stories are welkom

    greets kwijlebabulus
     
    kwijlebabulus, Aug 21, 2004
    #1
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  2. kwijlebabulus

    Mike F Guest

    The difference between M47 5th gear and M46 overdrive is so small as to
    be not worth thinking about. The 3.54 ratio would make a noticeable
    difference. (The last manual transmission 240s over here had 3.31
    axles.)

    --
    Mike F.
    Thornhill (near Toronto), Ont.

    NOTE: new address!!
    Replace tt with t (twice!) and remove parentheses to email me directly.
    (But I check the newsgroup more often than this email address.)
     
    Mike F, Aug 23, 2004
    #2
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  3. hello mike


    Thanks for the advice. I will probably take the 3.54.

    Has it any influence on the acceleration in the lower gears?

    greets kwijlebabulus
     
    kwijlebabulus, Aug 25, 2004
    #3
  4. kwijlebabulus

    Mike F Guest

    I've never changed a rear axle, but a 5% higher ratio (lower number) has
    to reduce torque available to the wheels by 5% at a given road speed.
    That said, you gain something back because you hold each lower gear 5%
    longer.

    --
    Mike F.
    Thornhill (near Toronto), Ont.

    NOTE: new address!!
    Replace tt with t (twice!) and remove parentheses to email me directly.
    (But I check the newsgroup more often than this email address.)
     
    Mike F, Aug 25, 2004
    #4
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