[xdrive_320i]

Hello all,

First off, apologies if this is in the wrong forum but I figured this topic applies to all F30 engines & trim levels. Anyways, on to the fun stuff.

In the far future, I'm planning on converting my F30 to full electric propulsion. After reading about the benefits of EVs both environmentally & performance-wise, I'm ready to embrace the future and make a fast, eco-friendly sleeper of an F30.

Some details to get out of the way:
1) No, cost won't be an issue here. I'll try to save $$$ where possible but this is entirely for fun and the learning experience.

2) I would like all the stock gauges and comfort functions (ex. seat heating) to work; however, getting iDrive to work with a project of this level is probably wishful thinking. Anyways it seems like an excellent lesson in coding if I ever reach that point of know-how.

3) The reasons I chose a manual transmission are:
a) More fun of course!

b) Ability to completely stop the flow of power from the motor to the drive-train in case of an electrical/otherwise fault

c) Mechanically, I don't envision it being terribly difficult. After some initial searching, it seems that an auto-to-manual swap is just a matter of swapping manual parts into an automatic car, and the coding is the difficult part. Obviously I don't need that level of electrical integration in this situation, but I understand that this may very well not be the case

d) I'm not sure if I'm up for the task of isolating the TCU and related components and modifying them for this project. I feel that the benefits (and fun!) of the MT outweigh the challenges of coding the AT, unless there is an easy solution to custom code a TCU in this regard

That's about it for the plans & ideas right now. Gimme any and all comments. Excited to hear what you guys think!

[njdangelo]

I think a manual is out of the question as electric motors don't use transmissions at all AFAIK. Still sounds like a fun project! Good luck and looking forward to the build theead

[328iX]

There's EVs out there that have transmissions. Granted they're low power.

Higher power output EVs only have 1-2 gears at most due to high torque.

It's a big undertaking mainly to get BMW modules to communicate together once modified but I'm sure it's possible.

[oranga]

Very interesting idea indeed. Are you planning on doing all or most of the work yourself?

What electric drivetrain are you planning on using? Are you planning on finding a wrecked Tesla and pull motors and batteries from there?

I am all for manual transmissions as well, but I would forget about it in this case. Electric motors have instant torque delivery (which is why Tesla's, especially in top spec trim, are such drag strip monsters) and don't need a multi-speed transmission. Yes, I know cars like the Ford Cobra Jet exist and combine electric motors with a manual transmission, but that's not what I'm imagining here.

Which brings up the question of packaging. Teslas have a "skateboard" chassis where the batteries make up the floor of the car. Its a clever way to spread the weight and keep the center of gravity low. You unfortunately won't be able to do that with an existing unibody design like our cars. Which leaves the trunk, under the hood, or where the gas tank sits (won't need that anymore), as the most likely place to put batteries. I imagine you could split them between locations to spread weight. Actually, you'd almost have to split them because if you put all the weight in the back, and without anything under the hood, you'd have no weight over the front wheels!

As for motors, if you wanted to stick with just RWD, the motor could be mounted on or near the rear subframe. Without the gas tank, driveshaft, and muffler, you might be able to make room for it, and maybe some batteries.

If you wanted to make it AWD, then you could mount another motor and batteries under the hood to drive the front wheels. Should be plenty of room under there without a gasoline engine!

I'm sure there are lots and lots of things to consider still, but just some big picture stuff that I thought of. Would love to see how this goes. Good luck!

[xdrive_320i]

Originally Posted by 328iX

It's a big undertaking mainly to get BMW modules to communicate together once modified but I'm sure it's possible.

Yup, this is what I suspected as well. I looked into how BMWs are coded from the factory and there are predetermined alphanumerical combinations (ex. 6TRH) that are entered into the ECUs based on the options the car has. This is how people can "add" features to their car (a popular example is Bimmercode) by adding/removing those codes that tell the ECU what to enable/disable. The obvious caveat here is that there are no configurations of the car with full EV propulsion so it would be a massive undertaking to get the stock modules to work.

[xdrive_320i]

Originally Posted by oranga

Very interesting idea indeed. Are you planning on doing all or most of the work yourself?

What electric drivetrain are you planning on using? Are you planning on finding a wrecked Tesla and pull motors and batteries from there?

I am all for manual transmissions as well, but I would forget about it in this case. Electric motors have instant torque delivery (which is why Tesla's, especially in top spec trim, are such drag strip monsters) and don't need a multi-speed transmission. Yes, I know cars like the Ford Cobra Jet exist and combine electric motors with a manual transmission, but that's not what I'm imagining here.

Which brings up the question of packaging. Teslas have a "skateboard" chassis where the batteries make up the floor of the car. Its a clever way to spread the weight and keep the center of gravity low. You unfortunately won't be able to do that with an existing unibody design like our cars. Which leaves the trunk, under the hood, or where the gas tank sits (won't need that anymore), as the most likely place to put batteries. I imagine you could split them between locations to spread weight. Actually, you'd almost have to split them because if you put all the weight in the back, and without anything under the hood, you'd have no weight over the front wheels!

As for motors, if you wanted to stick with just RWD, the motor could be mounted on or near the rear subframe. Without the gas tank, driveshaft, and muffler, you might be able to make room for it, and maybe some batteries.

If you wanted to make it AWD, then you could mount another motor and batteries under the hood to drive the front wheels. Should be plenty of room under there without a gasoline engine!

I'm sure there are lots and lots of things to consider still, but just some big picture stuff that I thought of. Would love to see how this goes. Good luck!

Yes! I am planning on doing all of the work and fabrication! However I will contact a professional if I bite off more than I can chew

I am planning on using a motor called the Emrax 348 rated for 380Kw & 1000Nm of torque. It is an axial flux synchronous motor that weighs just 42KG dry. It's incredibly small for the power it produces and can 2 can be stacked for 760Kw & 2000Nm in the future

This also ties into the questions about packaging & transmission choice. Since this motor is so small, there should be plenty of space under the hood for batteries, even if I decide to go with a transmission since the whole unit is just 100mm thick. Of course, this also raises the question of the durability of the drive-train and how removing it from the equation would increase reliability and simplicity. Honestly, if the motor can fit in the transmission tunnel/rear subframe area without too much issue it might be better to go down the direct drive route. However, I do want to keep AWD but again, I have to do more research to fully map out the existing xDrive system, and I doubt that it'll handle so much torque in stock form.

Lastly, correct! My plan for batteries was to split them between the front and the rear. Since the gas tank is no longer needed and lots of space should be open at the front, I could try and balance/skew weight distribution according to how I want the car to handle.

But this will all have to wait till I have the funds & time to undertake such a project. Again, this won't be happening anytime soon (planning to start in 5 years at the earliest) but it'll be nice to bounce some ideas around and learn some stuff