Gearbox suggestions for 1.9TDI MX5...

Thread in 'Technical Questions' started by R31, Jun 24, 2016.

  1. R31

    R31 New Member

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    So I'm looking for gearbox ideas for my 1.9TDi MX5 (NB) conversion. Looking at getting around 450-500lb/ft out of the engine and need a suitable gearbox for the torque obviously getting the sensible ratios would be good as well though not as important as strength.

    Options so far:

    R154 - The obvious choice however hard to find and expensive to buy if things go wrong.

    Z33 - Late model 6 speed one, issues are the size and placement of the gearstick

    530d ZF Manual box - Cheap and readily available, unsure on how good they are in actual use.

    Any suggestions or thought feel free to add them!

    Cheers,
     
  2. Andy318ti

    Andy318ti Active Member

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    Bm box all day, cheapest to buy and newer.
    You'll probably have to make the adapter plate and clutch assembly up yourself, check friction plate diameters see if the bm plate will fit the tdi flywheel and possibly the clutch cover.
    Sounds a cool build, what you doing at the rear to take the torque?
     
  3. mati

    mati Member

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    No way a Z33 box will fit the NB chassis without cutting a lot of shit out. I'd say go with the BM box.
     
  4. R31

    R31 New Member

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    Thanks for the responses. I was worried about the Z33 box tbh, I'm going to head over and take some measurement of the BM box this weekend, fingers crossed!

    For the rear end going to use a skyline diff and modify the half shafts, waiting on getting the gearbox sorted till we decide which one exactly as we need to think about the ratio for it. We are expecting to have to get customclutch/flywheel so anything that isn't is just a bonus! As for adaptor plate again we will either make an adaptor or weld the bellhousing depending on which works better in application. Once we have the parts sorted shouldn't be to hard... Famous last words!
     
  5. jon07043278

    jon07043278 Well-Known Member

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    BMW gearbox definitely. Shifter length is so easy to modify too. I would go for a zf or v8 gearbox over the diesel though as the ratios are very short. BMW's have very long diffs.

    Love the project. Start a thread?
     
  6. Gooly

    Gooly Member

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    Skyline diff will be very short on a BMW box. If you want a nissan diff then try get an S14 UK Manual diff as they are 3.7; even that will be quite short though. You want a 3.5 or under really
     

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