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Thread: Racing clutch setup for reliability

  1. #1
    Senior Member FrankyGoes's Avatar
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    Default Racing clutch setup for reliability

    I'm undecided about what setup to use when replacing the clutch on the race car. This project is for this summer.
    In Sport class I have to retain the OEM design. I cannot use a single mass flywheel even though it would be cheaper in the long run but I digress.

    Choices are limited. It will be a new dual mass flywheel paired to an OEM Pressure Plate (PP) and clutch disk.
    I'm aloud to use an HD PP but it is quite a bit heavier. It is also more suited to take the beating racing imposes.

    I'm presently running on an OEM setup with the clutch delay valve (CDV) in place.
    About once or twice a season I screw up a down shift / heel & toe and load the clutch in the reverse direction.
    So far I've been lucky. I did not destroy the straps. I think it is because it usually happens at the limit of adhesion so the clutch does not get reverse loaded too badly. I also believe the CDV is spreading the application of the clutch (Or release) over a period of time instead of being an instantaneous event.

    Please feel free to correct me if my assumptions are incorrect.

    If I'm correct the plan would de to install an OEM PP and clutch (They can handle the power of the stock S52) to save the weight of the HD but have someone increased the size of the straps to make it 'pseudo' HD and delete the CDV to gain a couple of tenth per lap because of more efficient shifting...

    In my head this sounds perfect but I have doubts... Care to comment ?

    Thanks

  2. #2
    Hiding in the bushes Gregster's Avatar
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    Why on earth do you still have the CDV installed?????? That should have been taken out ages ago

  3. #3
    Senior Member FrankyGoes's Avatar
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    From your comment you obviously feel it is slowing me down more than I thought...
    Do you share my feeling that it does save my ass when I srew up a downshift ?
    Thanks

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    Senior Member Shardik's Avatar
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    ^ Oh YES !
    The E36's sometimes put themselves in the wrong gear.

  5. #5
    Hiding in the bushes Gregster's Avatar
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    Quote Originally Posted by FrankyGoes View Post
    From your comment you obviously feel it is slowing me down more than I thought...
    Do you share my feeling that it does save my ass when I srew up a downshift ?
    Thanks
    Seriously it`s the first thing that should be removed from any BMW even if driven on the street or track. Ive seen so many cases where people thought there clutch was going or gone, I removed the valve and boom no issues. On E36s and E46s you can remove the valve and just pull the hardline out a tad to connect it back on the clutch line.

  6. #6
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    As soon as I bought my pre-owned E82/135i, I removed the CDV and replaced the transmission mounts with stiffer ones (E46/M3). The stiffer mounts allow less tranmission movement and easier and more precise gear shifts under load, with a very light amount of NVH.

    The CDV bypass allows faster clutch enagement disengagement. Both of these mods really helped on the track as I was frequently hunting for gears under hard accelerataion/braking.

    Another thing I do, and you can call me anal, is change my tranny fluid every 2 months or so during lapping season. I also installed a DIMPLE magnetic drain plug on the tranny.

    These are all easy DIY's and make a large difference on the track, and health of your tranny...
    M-Sport 2011 135i w/6SPMT | 255/35+255/35 Dunlop Direzza ZII StarSpecs | Quaife 3.46 FD LSD | CDV delete | BMS clutchstop | BMS Oil Tstat bypass | ER FMIC & CP | N54Tuning DP | GC Street Camber Plates | M3 Front Control Arms & rear subframe bushings & transmission mounts | Cobb PTF Stg1 custom tune | PFC 08 brake pads | Hardbrakes Ti Heat shields | F30 brake cooling shields | Custom brake cooling ducts

  7. #7
    Hiding in the bushes Gregster's Avatar
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    On my E46 the best thing I did was change to solid engine mounts, and trans mounts. The noise and vibration isn't that bad as it's barely noticeable and it got rid of the "accordion" feeling in the drivetrain. Im taking out the rear sub frame and such soon to install delrin mounts

  8. #8
    Senior Member FrankyGoes's Avatar
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    I finally removed the CDV valve in the race car.
    It makes quite a bit of difference on upshifts.
    I think I was compensating before and letting the clutch go early.
    Now when I do that my head snaps backward Lol !!
    Maybe its the upgraded Clutch Master setup. Maybe both.

  9. #9
    AWD Rules Turbo_Bimmer's Avatar
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    I don't know if you already changed your clutch, but FYI, I'm using a South Bend Clutch (PP and disc) with my turbocharged E30 and I'm very happy. It grips well, and the pedal effort is similar to OE. On my previous E30 I was using a Clutchnet clutch (disc/PP) and found the pedal effort required to be too much. Also the Clutchnet was more of a ON-OFF engagement, good for racing but not in the street.

    http://www.dxdracingclutches.com/per...e-clutches.cfm
    I have no affiliation with them, just passing my experience.

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