# Planning RX8 with tesla rear DU unit build



## brian_ (Feb 7, 2017)

Do you really want to mount the drive unit upside down, or do you want to rotate it around the vertical axis and run it in reverse?

The first step would be to check the fit, with drawings, computer models, or even a physical (cardboard/foam) mockup.


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## tks007 (Feb 16, 2020)

Upside downwards. So like normal in the tesla but you fix the driveshafts and turn on the inverter, i will then flip forwards. Facing top down. Because i don't fancy running it in reverse all the time as far as i can tell bearing loads and gear teeth profiles are optimized for the forward direction. The breather plug will be relocated and the breather hole will become oil pickup? No clue yet. Just an idea what i had since i thought it must be doable. The external oilpump (if the internal one cant be used anymore) will replace the job of the internal one.
If i go that route i will place a an external filter also. Think on the newer units i saw them too.

Did i miss something?

For fitment my approach is a bit more practical. I got the engine unit here and i got the RX8.
Another option would be not flipping it but mounting it with an angle or in the normal position but from my gut feelings (pictures) that would be sub optimal. Basically its a bit like converting the drive unit to dry/drier sump.

Now if i only could get my hands on a couple of tesla model S logs......


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## wombat (May 5, 2019)

I have been looking at the same conversion myself and by my inital measurement the ldu will fit as tesla had it with minor boot modification and with mounts like teslabimmer did. Looking forward to see your progress im about 6 months from the start for me hopefully


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## tks007 (Feb 16, 2020)

Thank u guys for posting really appreciate it.
Brian if you can please react to my reaction. Perhaps I missed something in the conversion, I guess you are way ahead of us in the topic so feel free to correct me. Here to learn a thing or two .

@wombat ; The large one? That's an animal...I'm quite far with the controller what was your plan with it? I'm needing right now some more logs of Tesla's. If you help me i will later help you with fireing up yours. Do you have a link for those mounts?
can imagine the ldu to fit but hey would be nice!


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## wombat (May 5, 2019)

Yes i need to prove a point to a few people so ldu it is...
Pretty pointless amount of power.
My plan currently is to use the open inverter control board as it has canbus output that can be configured in theory to suit rx8 but more reasearch is needed.
Trying to make it as simple as possible.
The mounts were going to be similar to the teslabimmer design happy to share the cad design when it's done but this months and months away








Tesla Large Drive Unit Support Thread - openinverter forum


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## tks007 (Feb 16, 2020)

Ok, food for thought then. The openinverter is nice but for the legalisation in the Netherlands it means obtaining EMC certification for the complete vehicle and that's costly. Also I fear that the Tesla design is build to be more precise/efficient. And in my case I'm looking for DU efficiency.
I hope I find someone who helps me with a log so I can finish the software mock-up.


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## Isaac97 (Jun 3, 2019)

@tks007 - I'm also looking for logs, please let me know if you find any. I've googled a million times, found nothing.
I might be renting a Tesla in a week or so just to log data, maybe I can send you some of my results.

Have you considered contacting EVTV? Back in the day(2015) they had a unit running off recorded logs, so chances are they have a bunch around.

-Isaac


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## tks007 (Feb 16, 2020)

Hi Isaac, for which DU (model S) are you gonna look out? Let's stay in contact I had the same idea, to bite the bullet and rent one. Hopefully the software level matches...


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## Isaac97 (Jun 3, 2019)

I'm looking for rear unit info... I've got access to a LDU, not sure of the year though. That would be my test bed.
Any idea how to decode drive unit serial numbers?

I want to put a small rear unit into my car (LDU seems a little much for ~3100lbs of vehicle) -- so controlling that is my final goal.

I have read about people being able to update firmware over CAN -- EV-Controls does that for their LDU controller. They won't share though.

-Isaac


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## Isaac97 (Jun 3, 2019)

Another idea...

Apply for this job at Tesla!
Senior Motor Controls Engineer | Tesla

That should give access to the .dbc files.


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## MarkMark1 (May 11, 2021)

Any updates on this project? I’m having the same idea....


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## brian_ (Feb 7, 2017)

If this project (or someone else's RX-8 conversion) is still active, it might be worth considering a Model 3 drive unit instead of Model S/X. The Model 3 places the motor ahead of the axle line, and so it is both better for balance and seems to me to be more likely to fit with the RX-8 suspension. The design of the Model 3 suspension is the same as that of the RX-8 (and NC Miata).
The Model 3 rear track is only 71 mm (2.8") wider than the RX-8 (and the body width is only 79 mm 3.1" or wider), so it might even be practical (and perhaps easier) to swap the entire Model 3 rear subframe with suspension and drive unit into the RX-8 body, with a moderate fender flare.

The Model 3 drive unit was not used in conversions until recently because aftermarket and DIY support for control of the drive unit was not available, but I see that tiger82's Cobra has moved from Model S to Model 3 components and SuperfastMatt is doing a Model 3 swap (into an old Jaguar, using some commercially available control solution). The Model 3 synchronous motor doesn't have the cooling problem of the Model S/X induction motor.


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## MarkMark1 (May 11, 2021)

Thanks,

That is indeed food for thought....


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