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Thread: Any way to tell if LSD without ....?

  1. #1
    Join Date
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    Any way to tell if LSD without ....?

    ... Jacking up the car etc. The vin will not give that information? I can't for the life of me find any info on how to find out if it has LSD without getting under the car. I won't be able to get a jack for another week. While we are at it... I can't find any decent info on where to place the jack safely on this thing.

    thanks,
    me.

  2. #2
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    You have to lift it and turn one wheel if the other turns you have a lsd. The likely Hood is high that you don't .

  3. #3
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    Quote Originally Posted by jclausen View Post
    You have to lift it and turn one wheel if the other turns you have a lsd. The likely Hood is high that you don't .
    if you have a lsd both wheels will turn the same direction, but if they turn different then its not lsd.

  4. #4
    Join Date
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    Quote Originally Posted by pofo View Post
    if you have a lsd both wheels will turn the same direction, but if they turn different then its not lsd.
    To avoid the unpleasant surprise that it could be a welded diff, it is best to remove the rear cover as well and take a look.

  5. #5
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    I recall the last time of checking the condition of an lsd, I just raised one wheel off the ground and measured the amount of torque it took to turn the wheel. I think it was about ~35 lbs/foot. I forget if this was with the trans in neutral and I'm too lazy today to verify!
    Tbd

  6. #6
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    Quote Originally Posted by mrvls View Post
    ... Jacking up the car etc. The vin will not give that information? I can't for the life of me find any info on how to find out if it has LSD without getting under the car. I won't be able to get a jack for another week. While we are at it... I can't find any decent info on where to place the jack safely on this thing.

    thanks,
    me.
    Basically no.

    If your car came with an LSD (looking at vin number) it could have been removed and sold for the money and replaced with an open diff - as I am doing with my 80 sport model.

    Or you could just drop the clutch at 2500 rpm and see if both tires spin (burn rubber) for the same distance.

    Always FUN TO DRIVE - Build Thread & Tech info - 79 320/6 track car build thread -- Videos of track car -Adam in car Auto-x video - Start-up video - 4/2011 Adam's TOP BMW time San Diego BMWCCA - 4-5-15 Dyno break-in run new M20B25 - Exhaust Thread - Link

  7. #7
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    Did a quick video for testing per-load lockup breakaway of a 3:91 E21 rebuilt and modified LSD. By modified I rebuilt it with thicker dogeared drive plates (.083") and also added an addition .020" shim to each side. This netted a per-load breakaway of 55 to 58 ft-lbs of torque after 250 miles of break in driving on it.

    Note: mrvis if you do not have an LSD, doing this test will show about 2 to 5 ft-lb of torque needed to turn the wheel off the ground as long as you do not have a dragging set of brake shoes.

    Side note in video played with added some free usable background music, looking for more places to get usable youtube legal music.

    https://www.youtube.com/watch?v=4AmMbAS8Gsc



    Last edited by OLD MAN; 10-01-2018 at 08:14 AM.

    Always FUN TO DRIVE - Build Thread & Tech info - 79 320/6 track car build thread -- Videos of track car -Adam in car Auto-x video - Start-up video - 4/2011 Adam's TOP BMW time San Diego BMWCCA - 4-5-15 Dyno break-in run new M20B25 - Exhaust Thread - Link

  8. #8
    Join Date
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    1980 BMW 320i E21 M10B18

    Cool

    They had the Letter "S" on them, originally.
    s-l1600.jpg

    Randy

  9. #9
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    Quote Originally Posted by OLD MAN View Post
    Basically no.

    If your car came with an LSD (looking at vin number) it could have been removed and sold for the money and replaced with an open diff - as I am doing with my 80 sport model.

    Or you could just drop the clutch at 2500 rpm and see if both tires spin (burn rubber) for the same distance.
    DROP IT AT 5500 rpm with steering turned to the left

  10. #10
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    Quote Originally Posted by mihajlo View Post
    drop it at 5500 rpm with steering turned to the left
    even better!!!

    Always FUN TO DRIVE - Build Thread & Tech info - 79 320/6 track car build thread -- Videos of track car -Adam in car Auto-x video - Start-up video - 4/2011 Adam's TOP BMW time San Diego BMWCCA - 4-5-15 Dyno break-in run new M20B25 - Exhaust Thread - Link

  11. #11
    Join Date
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    Quote Originally Posted by OLD MAN View Post
    Did a quick video for testing per-load lockup breakaway of a 3:91 E21 rebuilt and modified LSD. By modified I rebuilt it with thicker dogeared drive plates (.083") and also added an addition .020" shim to each side. This netted a per-load breakaway of 55 to 58 ft-lbs of torque after 250 miles of break in driving on it.

    Note: mrvis if you do not have an LSD, doing this test will show about 2 to 5 ft-lb of torque needed to turn the wheel off the ground as long as you do not have a dragging set of brake shoes.

    Side note in video played with added some free usable background music, looking for more places to get usable youtube legal music.

    https://www.youtube.com/watch?v=4AmMbAS8Gsc

    Great video Daryl!
    Tbd

  12. #12
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    Quote Originally Posted by epmedia View Post
    Great video Daryl!
    Thanks - playing with new video editing software and looking for free music to add. Made it without music and wanted to turn it off... LOL

    Always FUN TO DRIVE - Build Thread & Tech info - 79 320/6 track car build thread -- Videos of track car -Adam in car Auto-x video - Start-up video - 4/2011 Adam's TOP BMW time San Diego BMWCCA - 4-5-15 Dyno break-in run new M20B25 - Exhaust Thread - Link

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