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    Wavetrac + M3 Bushings Installed, 1st Gear Thump

    So I know that most of you guys have an LSD. I just installed my Wavetrack and have this odd issue. If I sit at a light in neutral, and then clutch in and shift to 1st with clutch still depressed, the car will "thump" and it feels like a small amount of power is going through the drivetrain. I expected the "click" at takeoff when the LSD internals lash together, but this is with no power applied at all. I thought that either 1) the old subframe bushings and OEM open diff used to absorb this thump and I wouldn't notice it or 2)the zero-load LSD is "locked" from a stoplight, tranfering this load moreso to the wheels. Do you guys get this "thump" going into 1st?

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    Yes, its there on all the 6MT's with a Wavetrac. If you search e90post or possibly even on here (not sure how far back that was) you'll see me struggling trying to realize what it is Click here to enlarge In the end attribute it "racecar" noises. Quaife on a 6MT does it too apparently according to some although others say it can be setup not to thump when going from neutral into 1st as you described.

    I'm getting a Quaife 2.56 now, swapping out my 3.08 Wavetrac, and we'll see if the same thump is still there. This time the 2.56 quaife unit has been set up entirely by HP Autowerks.
    Click here to enlarge

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    yes i get the same thump going from neutral to 1st. Its normal and wont damage anything.



    Click here to enlarge Originally Posted by Tzu Click here to enlarge
    So I know that most of you guys have an LSD. I just installed my Wavetrack and have this odd issue. If I sit at a light in neutral, and then clutch in and shift to 1st with clutch still depressed, the car will "thump" and it feels like a small amount of power is going through the drivetrain. I expected the "click" at takeoff when the LSD internals lash together, but this is with no power applied at all. I thought that either 1) the old subframe bushings and OEM open diff used to absorb this thump and I wouldn't notice it or 2)the zero-load LSD is "locked" from a stoplight, tranfering this load moreso to the wheels. Do you guys get this "thump" going into 1st?
    ground control coilovers/wavetrac lsd/ full m3 suspension/delrin bushings/ megan racing toe and camber arms/bmw oem performance carbon fiber front lip and rear deck spoiler/m3 strut brace/ecs SS brakelines/CPE dci's, charge pipe, catless dp, fmic/bms OCC/tuningtechfs custom tune/defiv diff lockdownkit,rbpcv valve.

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    Click here to enlarge Originally Posted by TRES Click here to enlarge
    wont damage anything.
    ..and I'm sure @Tzu knows just how shy I've been with it on my car Click here to enlarge Other than that thump, which you'll get used to and learn to ignore, its a really solid great performing unit.
    Click here to enlarge

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    Wasn't your issue a worn CV joint and it went away when you went to DSS axles? I've searched all weekend and it seems like SOME 6MT cars have it and some don't. I'm just thinking about the amount of force being fed through the driveshaft to make it thump like that. It's way more than I could impart by shocking a rotational force onto the driveshaft my hand. It's got to be bad for the synchs.

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    No, that was a "vibration" I was having due to my rear axle CV.
    Click here to enlarge

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    I had vac motorsports explained it to me has something to do with how the diff was machined. (the surface that bolts to the final gear is not 100% flat) you can give them a call and get the full explanation. Cant remember the details, i'm done with drivetrain/suspension just need a little more performance 40 - 50 whp and my car will be complete.
    ground control coilovers/wavetrac lsd/ full m3 suspension/delrin bushings/ megan racing toe and camber arms/bmw oem performance carbon fiber front lip and rear deck spoiler/m3 strut brace/ecs SS brakelines/CPE dci's, charge pipe, catless dp, fmic/bms OCC/tuningtechfs custom tune/defiv diff lockdownkit,rbpcv valve.

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    Well VAC is on this forum. Maybe they can chime in?

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    My Wavetrac is going in next week (6MT, 3.08). I'll let you know if mine does the same thing Click here to enlarge
    [02/07 E92 335i 6MT] - Under Construction

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    I have it too with Quaife. I think it’s the tolerances between LSD and open designs. When static you’re moving the drivetrain (input, output, or combo) putting the box into gear. And first is the larger gear difference. I bet you try into higher gear less noise cause the input shaft is moving easier.

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    i have a quaife and I dont recall any 'thump' noise or vibration/feeling. with the radio off, all i hear is the 'click' when the shifter moves through the gate. this is an interesting discussion though.... i'm curious as to technically, mechanically, what is making the wavetrac diff 'thump'... but with Josh's recent post, i guess it is not only with wavetrac.
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    Mods: Check the Garage

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    Yup, same here. I love that mechanical engagement I get with my wavetrac LSD. It gives you that lock and load feeling. Click here to enlarge

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    I have a slight thump with my Quaife LSD. It's not always there though, seems like it happens only when I've been sitting at a light for a while. It won't happen if ur sitting there and go from out of gear, to first, and back out of gear real fast.
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    ESS 6XX kit

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    Concur with bobs. It only happens to me once after sitting in neutral at a light. The drivetrain is already positively loaded if you're moving forward and come to a stop. Then from neutal, going into any gear (I've tried gears 2 through 4), the thump is there and equally as bad. However, if I unload the lash by rolling backward say 10cm, the thump will not be there as I assume its being absorbed through the unloaded drivetrain. It's driving me nuts!
    Last edited by Tzu; 08-13-2012 at 01:48 PM.

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    Same on my car with the wavetrac .. you'll just learn to live with it..try driving a 6mt m3, same will happen...because racecar
    Click here to enlarge

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    Having never driven a 6MT M3, I'm not really convinced that BMW will sell a car that shudders every time you go into 1st from a light. Maybe mine is just worse than what everyone else is experiencing. Or maybe it wears in and becomes less noticeable over time? Hell I took it for an alignment Saturday and the first thing the tech said after driving it 30ft from service to the alignment station was "You have some terrible clunk comming from the diff."

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    I've driven my buddy's '08 6MT E92 M3 and his diff makes all sorts of clunky noises Click here to enlarge If you dig up on the m3 forums (doesn't need to be E9x) you'll see what they say about thump and LSD noises.

    For something "very" related, check this out this thread, 1M clunking/thumping:

    http://www.1addicts.com/forums/showthread.php?t=718087

    Its normal, nothing to worry about, just ignore, race car noises Click here to enlarge
    Click here to enlarge

  18. #18
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    Hmmm Tzu, yours sounds worse. Mine doesn't make a loud thump. You would only notice it if you were driving and the you can BARELY feel it. You can't hear the thump, you just feel it ever so slightly.
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    I do indeed feel it, and somewhat hear it. I can feel it down my back and it's very evident. Even my passenger said "wtf was that?" Maybe I am overthinking it. I probably just need to reassure myself that it happens to other cars by feeling it on a car other than my own.

  20. #20
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    Mine is definitely not that bad....

    But you have a wavetrac right? So maybe thats the difference....I think its normal either way.
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    ESS 6XX kit

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    1 out of 1 members liked this post. Yes Reputation No
    Click here to enlarge Originally Posted by dzenno@ProTUNING Freaks Click here to enlarge
    I've driven my buddy's '08 6MT E92 M3 and his diff makes all sorts of clunky noises Click here to enlarge If you dig up on the m3 forums (doesn't need to be E9x) you'll see what they say about thump and LSD noises.

    For something "very" related, check this out this thread, 1M clunking/thumping:

    http://www.1addicts.com/forums/showthread.php?t=718087

    Its normal, nothing to worry about, just ignore, race car noises Click here to enlarge
    I fitted an m3 diff on my 6mt and I totally agree with Dzenno, the noises that come from the diff are really noticeable. Mine clicks and thuds when at slow speeds but I've managed to lean over and turn my music up to drown out the noises Click here to enlarge
    Alpine White 2008 6MT 335i - Cobb AP - PTF Tuned - RB Turbos - AR DPs - VRSF 3.5" exhaust - Custom FMIC - 380mm BBK F&R - BMS DCI - M3 DCT LSD - Whiteline subframe bushes - M3 Sways and rear arms - M3 wishbones - ER CP - Spec Stage 3+ clutch and steel SMFW - AST 4100 Coilovers - UUC DSSR -UUC Black tranny mounts - TMS Alu diff bushes - Forge DVs - Aquamist HFS-4 meth - Alufelgen CS7s - BMWP V1 Steering Wheel

  22. #22
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    Click here to enlarge Originally Posted by Tzu Click here to enlarge
    Well VAC is on this forum. Maybe they can chime in?
    @Mike@VAC

    Stage 2 or 2.5 E9X M3 S65 V8 supercharger kit for sale
    : http://www.boostaddict.com/showthrea...r-kit-for-sale

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    It's hard to diagnose something like this without hearing/feeling it. I can say that we have done a few diffs and the clients came back concerned with a slight clunk. 100% of the time its a normal sound, sometihng that happens stock. I even had to bring a client out in our bone stock 128i so he could experience the same clunk. My WWD Acura TL also clunks the same way. Most of the time its normal.

    @dzenno@ProTUNING Freaks - Click here to enlarge

  24. #24
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    Click here to enlarge Originally Posted by Mike@VAC Click here to enlarge
    It's hard to diagnose something like this without hearing/feeling it. I can say that we have done a few diffs and the clients came back concerned with a slight clunk. 100% of the time its a normal sound, sometihng that happens stock. I even had to bring a client out in our bone stock 128i so he could experience the same clunk. My WWD Acura TL also clunks the same way. Most of the time its normal.

    @dzenno@ProTUNING Freaks - Click here to enlarge
    Why the sad face?
    Click here to enlarge

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    One example of a member that doesn't have it. I'm keeping my fingers crossed lol
    Click here to enlarge Originally Posted by DefactoM6 Click here to enlarge
    ... Also happy to report that my Wavetrac is dead silent...not only does it not thump like others have in the past, there are people who complain with Quaifes and Wavetracs about them making clunking noises when engaging first gear. I have no such issues, just awesome, two tire fire.
    http://www.e90post.com/forums/showpo...99&postcount=9
    [02/07 E92 335i 6MT] - Under Construction

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