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Thread: E30 diff ratio

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    Club Guest orangebmw's Avatar
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    E30 diff ratio

    hi guys..just wanna ask what is the diff ratio of std 320i e30? is it 4.10?
    what is the best diff for E30? is it 325i?

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    Club Guest kevster30's Avatar
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    M40B18/M10B18 uses 3.9.1 or 4.1.0

    M20B20 uses 3.7.3 or 3.9.1

    M20B23 uses 3.7.3 or 3.9.1

    M20B25 uses 3.4.5 or 3.7.3

    The ratios differ among the different markets and regions


    Drive any BMW in anger, you will discover it's SOUL!


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    Club Guest sgbuloh_e90's Avatar
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    Quote Originally Posted by orangebmw View Post
    hi guys..just wanna ask what is the diff ratio of std 320i e30? is it 4.10?
    what is the best diff for E30? is it 325i?
    depends on ur style of driving i guess.

    have tried both 3.91 & 3.73 open diff (non LSD both)

    3.73 = better highway cruising speed (less rpm at high speeds)

    3.91 = better acceleration , much higher rpm @ highspeeds if compared to the 3.91 diff.

    of coz driving with a 3.91 diff consumes bit more petrol but u gain better acceleration .

    i heard 4.10 is the best for acceleration , but i may be wrong.

    hope this helps.

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    Club Guest al3dx's Avatar
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    What is diff ratio?

    Loving What I Drive & What I Do Best

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    Club Guest sgbuloh_e90's Avatar
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    gear ratio = The gear ratio is the relationship between the number of teeth on two gears that are meshed or two sprockets connected with a common roller chain, or the circumferences of two pulleys connected with a drive belt.

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    Official Member turbology's Avatar
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    differential ratio is different from gear ratio. But the idea is the same.
    To simplify:

    If differential ratio is 4.0:1
    Your driveshaft needs to turn 4 revolutions , to turn 1 rotation on the wheel.

    Hope this help.
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    Club Guest sgbuloh_e90's Avatar
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    lol ..i got confused. thanks 4 clearing that up

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    Club Guest al3dx's Avatar
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    I understand that... THanks..

    Loving What I Drive & What I Do Best

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    Club Guest orangebmw's Avatar
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    thanx guys for the info...i wish to have e30 diff with lsd...gonna drift it!

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