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Thread: OE flywheel help needed

  1. #1
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    OE flywheel help needed

    If anyone has an original Z8 dual mass flywheel lying around, would you please measure the distance from the mounting surface (where it mates with the crankshaft) to the friction surface (where the clutch disc comes into contact) and post it here. Inches or metric is fine. Or, if your Z8 is due for a clutch replacement, would you ask the shop to take the measurement when they have the transmission out of the car. I would truly appreciate any help you can provide.

  2. #2
    Z8 Addict Z8doc's Avatar
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    Wondering if this info mght be on the M5 boards somewhere considering the identical transmissions.
    Best Regards,

    Jeff
    61995 Silver /// Rot - Original Owner
    Z8 Club of Germany e.V. #102

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    As it turns out, while the transmissions used in the e39 M5 and the Z8 are the same, the clutch components (including the flywheel, pressure plate, disc, slave cylinder, and master cylinder) all have different part numbers for the two cars. I am trying to establish the dimensional differences between the 2 set-ups since I have experienced clutch throw problems when installing aftermarket clutch kits in Z8s. The UUC Ultimate kit is an exception since it uses its own unique clutch slave cylinder and a shortened push rod due to the radically different dimensions of the V-12 sourced clutch components. As a result, it is interchangeable between the two cars. Apparently, most aftermarket clutch suppliers just assumed that they could measure an M5 OE clutch kit and use those dimensions to build a kit for the Z8 also, but my experience indicates this is not the case. So what I need is a measurement off of an OE Z8 flywheel (already have the OE clutch components) to be used to develop a proper kit for use in Z8s.

  4. #4
    Z8 Addict Z8doc's Avatar
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    I have sent an email to J?rgen with the Z8 Club of Germany to see if he can get the answers to your questions and to find out the design rationale from BMW as to why they decided or felt the need for two different setups (which I believe also included the Z8 having the CDV and the e39 M5 did not if I remember correctly). Hopefully the Club can help, given their access to the engineers who worked on the project. I will let you know when I hear something.
    Best Regards,

    Jeff
    61995 Silver /// Rot - Original Owner
    Z8 Club of Germany e.V. #102

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    Thanks so much for your help! It is also interesting to note that the pulley configuration for the auxiliary drives on the front of the S62 motor is different on the Z8 and the M5. Plus the water pumps are different. There must have been a good reason for these differences but I am at a loss to explain them.

  6. #6
    Z8 Addict Z8doc's Avatar
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    J?rgen let me know that he has contacted some of the engineers who also are Z8 owners and that prompted them to look at many things and noted there are many, many differences between the S62 setup of the Z8 and M5. They are investigating and hopes to have some information soon but it may take some time. However, he also stated that there are many differences including that the two cars do not share the same performance programing either (even though they have similar performance) hence there may be differences in the response of the Z8 to software reprogramming like the Shark Injector as compared to what you might get from the same thing in the e39 M5. Just another apparent difference among many. I will let you know when I hear something.
    Best Regards,

    Jeff
    61995 Silver /// Rot - Original Owner
    Z8 Club of Germany e.V. #102

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    I can't thank you enough for helping out in this matter and look forward to hearing what the factory has to say. Based upon my extensive experience with modifying Z8s, I believe most aftermarket parts/program manufacturers have assumed that if they develop a product for the e39 M5, it will work on the Z8, too. I can't tell you the number of times I've ordered aftermarket parts for a Z8 only to discover they don't fit/work properly. In every case, the parts are listed as compatible with e39 M5s and Z8s. The reason for this confusion is obvious: there were a lot more e39 M5s built than Z8s and M5 owners are much more likely to modify their cars than Z8 owners. After all, an e39 M5 is just a nice mode of transportation while a Z8 is a true classic with real collectibility potential. So the manufacturers respond to demand for e39 M5 hop-up parts and then just assume they can broaden the market by including the Z8 on the compatibility list, without ever checking to see if everything works properly. In fact, many of the manufacturers I have spoken with have never even seen a Z8! Please keep this in mind if and when you are looking for aftermarket parts for your Z8.

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    Z8 Addict Z8doc's Avatar
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    I have not heard back from him yet but in my conversations with him at the meeting in M?nchen in September, I know one focus of the Club this year is to try and identify some of those differences with the idea of the Club handling the manufacturing, sale and distribution of various replacement and aftermarket parts for the Z8, both Short term and long term. I personally noticed the aftermarket issue with the recent addition of the Shark Injector,which is advertised as "compatible with the e39 M5 (and Z8)" is the way they list it.... which clearly delineates your comments above, that it really is for the e39 M5 and (by the way, the Z8 by default) which is really not the case. The ECU/DME is a completely different part no. and hence, I suspect, the software programming is different too and hence, one really may not be able to expect the same out of the Shark Injector as you can the e39 M5. I confirmed with J?rgen that the software is not exactly the same and hence, the dyno results of the Shark really made no significant increase in torque or HP but, the throttle body response is definitely noticed so for now, I am leaving it in. Again, I will let you know when I hear something and thanks for your input over the years. It is most appreciated -- hope to meet you sometime, are you going on the Pacific Northwest Drive -- it is just a short drive over the Mountains from Montana?
    Best Regards,

    Jeff
    61995 Silver /// Rot - Original Owner
    Z8 Club of Germany e.V. #102