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Just a few progress pictures of my ongoing DCT swap in a 92 miata.
Im installing a 7 speed dct box from a 2016 M4, "because i can".
It will fit the BP with a slightly modified Kmiata adapter plate, but pretty much everything else will be custom made.
it will fit in the transmission tunell, and for a 450whp street/trackday car it will be plenty strong, and have a higher top speed/lower rpm for cruising/autobahn driving(200mph miata?)
I presume shifting is solenoid activated and not pneumatic as it would be on a race sequential box. If this ends up costing less than about 11k USD, it would be cheaper than the Quaife QBE6OG.
If memory + a cursory google serves correctly, about 2.2x (~80 lbs for a six spd vs. 82 kg dry weight of 7DCI700) ignoring adapter plates, clutch/pressure plate hardware differences (or lack thereof) and driveshaft length changes.
I'm fairly sure you already know this if you're doing this swap, but worth mentioning anyways. Check the fluid pan gasket and the mechatronic sleeve area on it. It's a somewhat common occurrence for them to leak fluid and when/if it gets low enough, the clutch packs can start to overheat. Had a rather long drawn out experience with the 7 spd DCT box years back in my old 135i and learned entirely too much about them.
Paddle shifters are parts for high end gaming rigs, but the paddle and the mounting plate is my own design, machined from 4mm carbonfiber.
One of the buttons with the green light is a Neutral gear button, the other changes page on my dashlogger.
The red **** changes between power level of the engine, and traction control settings, 6 in totalt between 300whp and full wet mode tractioncontrol, low or high power with dry setup tractioncontrol, or full power with no tractioncontrol.
Paddles send a signal to a external transmission control ecu, and gearbox internals are modified. we do not use the BMW TCU unit. all valves and position sensors etc er directly connected to the new standalone unit.
This allows full adjustability of shifting times++ and i still have a clutch pedal (drive by wire clutch) .
It will be as if the car had a race sequential gearbox. Clutch in, select first. and then only use paddles after that. But it also allows a driver to clutchkick if used for drifting, this is not normally possible with a DCT transmission!.
Shifting is also more aggressive than with the stock TCU unit, and clutch pressures are also adjustable.
It will also be able to control a automatic function from my ECU, making it send gear up/down signals, and making this fully mappable aswell.
All seals on the gearbox will be changed Sometorque
A used DCT box from a M4 cost us 1000 euro, and the rest of the conversion parts are similar, but not the same as K miata manual swap parts.
The gearbox is TALL and i have had to raise the engine a bit to make this work, but my car is 99% a streetcar, with some trackdays inbetween.
The ratios are typical BMW with a short 1stk. but 3-4-5-6 is the same as the miata 6 speed, but with a 7th at 0.67 on top of that.
For street use ( i also sometimes drive on the autobahn) a gearing to over 200mph is sweet as hell and with 450 whp it will still rip through the lower gears.
There are some problems doing this swap, but it helps not having the canbus controlled stock TCU. and installing it in a light and low(relative) power car like a turbo mx5 should make the mechanics of the gearbox pretty much bulletproof.
I presume shifting is solenoid activated and not pneumatic as it would be on a race sequential box. If this ends up costing less than about 11k USD, it would be cheaper than the Quaife QBE6OG.
It will be cheaper. but heavier. but more streetable
03-23-2019, 06:03 PM
7speed getrag DCT transmission swap.
14
and with 450 whp it will still rip through the lower gears.
