The TesLorean

[Tamir A.]

Smart man.

That was me

[DrJeff]

I would expect a true traction control system to actually requires sensors at all 4 wheels. Similar to ABS. I think a better solution would be to limit the power output at certain RPMs. Wait until you know the car would be moving and then have the controller ramp up power. This is also assuming you go with a fixed gear setup and the motor reports RPMs. It wouldn't be optimized for all conditions, but could at least keep you from breaking the wheels loose all the time and damaging the motor mounts.

Even with the reduced power at lower RPMs, you should still have a nice instant torque feel. Even though I've had an EV for nearly 3 years now, it still amazes me that when on the freeway I can floor it and the car starts accelerating even before I can get the "gas" pedal all the way to the floor.

If I go with the Tesla drive unit, it includes the transmission (single gear - sandwiched between the inverter and motor). The transmission differential is not limited slip, so you could have one wheel spinning and another stationary (admittedly unusual conditions - oil slick under one wheel) - but with the high instant torque it is more likely that in an stock (engine) car. My plan is to put a pulse unit in place of the Lambda counter to get an independent read of the vehicle road speed and to compare that to the 1) the motor rotation and 2) the speed from each rear wheel. The vehicle speed to the motor rotation might be enough of a clue to command the power controls to ease off (whether both wheels are spinning or one is spinning).

One thought one reading the rear wheel speeds is to combine a variable reluctor sensor (http://www.megamanual.com/ms2/pickups.htm) mounted so as to detect the passing bolt heads at the CV joint or at the transmission end of the driveshaft. Alternatively the bolts could 'host' magnets somehow, a hall effect sensor might be more reliable. The bolts at the end of the driveshafts have the advantage of holding a fixed position (even with suspension travel) relative to other mounting points.

Other Tesla investigators have indicated that the Tesla uses the electronic brakes on the rear to act as a support for traction control. If a wheel begins to spin - apply a momentary brake, to provide the other wheel with some drive. I can't validate that this is the method, but it sounds plausible. Would I want to drive a vehicle with a home made system that could selectively apply the brakes to a wheel if it detected a slip? Hmm, not sure about that. Would I be more comfortable with a system that just detected if the vehicle speed varied greatly from the motor speed and adjusted the motor speed accordingly? A bit better, if the vehicle speed detector was reliable enough. Would having four sources of vehicle/motor/wheels speeds be a good idea? I think so, if it can be done.

Jeff

[DrJeff]

Two photos of the rear motor from a 2015 Tesla 70D (dual identical motor version), 259HP drive unit. The drive unit includes the motor, the inverter (DC to AC), and the transmission. The photo with the front suspension parts gives a good impression of the unit size. Suffice to say it's small.

Tesla Drive Unit and DMC-EV.jpgTesla Drive Unit and Front Suspension Parts.jpg

I'm under no illusion that this is going to be easy or quick, or supported by vendors, or anything other than going where no one has gone before.

This is going to be fun.

[delgato]

Two photos of the rear motor from a 2015 Tesla 70D (dual identical motor version), 259HP drive unit. The drive unit includes the motor, the inverter (DC to AC), and the transmission.

Wow that is cool. Were you able to buy that unit new from Tesla direct or is it from a wrecked out car?

I would be really interest what that cost however, I would understand if you did not answer that.

Is there other proprietary parts needed with that motor set up?

For instance will you need a Tesla controller and other Tesla specific parts to get that working correctly?

I am very interested in what you are doing there. I am planning to do an EV with my car once it is back together.

I had thought of the Tesla set up but was unsure if a motor was obtainable.

I would love to see lots of pics of your progress as it goes. I am really interested to learn how you end up mounting the motor, batteries, and everything else.

I have a bunch of other questions once you get a bit further into this build.

Keep us posted please.

Good luck to you.

[Chris4099]

Wow that is cool. Were you able to buy that unit new from Tesla direct or is it from a wrecked out car?

I would be really interest what that cost however, I would understand if you did not answer that.

Is there other proprietary parts needed with that motor set up?

For instance will you need a Tesla controller and other Tesla specific parts to get that working correctly?

I'm would expect it to be out of a wrecked car. Tesla doesn't sell many parts to general public. You can't for example, go to a Tesla service center and order up a 70kWh battery pack from the parts counter. You have to be a registered owner and have the part installed by them and they take the old part in return. So all these Tesla drive modules people have are from wrecked cars.

As for controlling them, there's already a guy that makes a controller board that speaks "Tesla" to the motor. Granted I haven't followed that carefully yet, so I'm not aware of any actual swaps it's been installed in yet. Just the last YouTube demo I saw was showing it controlling a Tesla motor on the work bench.

I too am looking forward to seeing how this turns out. As an owner of both a DeLorean and Tesla Model S, this hits close to home for me!

[DrJeff]

I've picked up your Questions and had a shot at Answers....

Q: Were you able to buy that unit new from Tesla direct or is it from a wrecked out car?
A: It is from a salvage 2015 Model S 70D. Looks like it hit a snow bank front on - about the best possible case for a salvage car. Written off due to repair costs - probably salvage decision mostly driven by the crack in the front frame. I got the rear motor. The rear was beautiful - as rears often can be.

Q: I would be really interest what that cost however, I would understand if you did not answer that.
A: Salvage teslas can be got for $20-30k (if they were flooded they could be $15-20k - but you'd be taking a significant risk as regards damage to the battery and electronics). The battery modules (if undamaged) are worth about $12-15k and find homes in automotive and non-automotive applications (solar panel backup power). My motor was advertised on 'DIY Electric Car' for $4500. Apart from the motors there are many interesting parts on the car.

Q: Is there other proprietary parts needed with that motor set up?
A: You need a battery pack that can support 400v and sufficient amps (C rating - the battery capacity can limit the HP output of the motor - you'll see references to "Battery HP"). The proprietary bits are the CAN codes that instruct the motor. The biggest challenge is going to be controlling the motor, either figure out the CAN messages that the motor responds to (EVTV has done this for the large rear motor in earlier and performance Teslas), or replace the motor controller (Michal Elias has done this - also for a large rear motor), or you could replace the controller and power stage (some developing examples here on other motors). So far as I know today - no one has 'controlled' the new 2015 motor out of the 70D model. So there's risk here, but I feel the trajectory of attempts and knowledge is heading in the right direction, and I hope to contribute to that.

Q: For instance will you need a Tesla controller and other Tesla specific parts to get that working correctly?
A: The drive unit includes the inverter and controller. The drive unit takes as input the + and - high voltage DC, and a CAN connection. The motor controller is included in the inverter.

Q: I had thought of the Tesla set up but was unsure if a motor was obtainable.
A: Only through salvage, although you could buy a Tesla and pick it apart. I've been surprised how many salvage Teslas are available, although the hassle of getting a salvage car varies from state to state, and the cause of the salvage is very important. The main reason for picking the smaller rear motor from the new 70D was fitting the motor into the space left when the PRV V6 comes out. The large rear motor from the earlier Tesla models and the performance models is over 30 inches wide. If you look at where the tesla transmission sits (between the motor and inverter) and where the drive shafts need to be located, it would have meant (essentially) removing and rebuilding the rear subframe and suspension of the Delorean to fit it in. The space at the bottom of our engine cradle is about 16-18 inches wide. The rear small Tesla motor stands a decent chance of fitting into the existing engine cradle (with the drive shaft out points in a usable position) - but I've no doubt some modifications will be needed, above and beyond mounts. I'm only going to know for sure once I lift the PRV/transmission out and trial lower the 70D in.

[DrJeff]

As part of the process of converting to Electric, lots of parts are no longer needed. My plan is to post them in the For Sale section on the forum. While some of the parts are standalone (new style fuel pump/sender unit), others could be bundled (EFI Conversion : megasquirt, fuel rails, low profile injectors, etc.). My plan is to bundle first, and if it doesn't sell, to list the items separately. There are so many items that I'm going to list them as I have them ready-to-ship, so it could take a while. I took an inventory of "parts already off the car" or purchased "waiting to go on car" in storage buckets and came to 200 separate items (not counting multiples), of which probably one third will be offered for sale. Items currently "yet to be de-installed from the car" probably account for another 20 items.

The item that I'm most curious about how to sell is the engine, as I've never sold or bought an engine before. At the moment the engine is stripped down at the top (heads still on), done to clean the valley in preparation for the EFI project that never was due to a house move.

Jeff

[DMage]

Suggest you reach out to the following members over @ teslamotorsclub.com - wk057, ingineer, and btr_ftw

All have torn into Model S components either through salvage dismantling or out of curiosity to bench test. Unless the motor is much simpler to apply signals to than I imagine, the hardest part will be the CAN communication to it that may require additional components.

[DrJeff]

Suggest you reach out to the following members over @ teslamotorsclub.com - wk057, ingineer, and btr_ftw

All have torn into Model S components either through salvage dismantling or out of curiosity to bench test. Unless the motor is much simpler to apply signals to than I imagine, the hardest part will be the CAN communication to it that may require additional components.

Yeah. I've been watching their work closely. Lots and lots of developing knowledge on how the model S is put together and how the parts of it can be re-used.

Good YouTube posting this morning by Jack Ricard of EVTV (go to minute 60 - at the 1hr mark). He talks about the smaller front motor used in the Tesla Dual motor model S.

Other people to watch are Michal Elias (replaced the motor controller on a Tesla full size motor) and Damien Maguire (building his own inverter). There are also other hobbyists on DIY Electric Car that are tackling the motor control challenges.

CANbus looks the most likely route for controlling the motor, but the alternative motor controllers provide some benefits to getting around the Tesla firmware already in the motor.

Jeff

[ucfierocharger]

Dr. Jeff, I'm a good friend of Nicholas R on the forum here, and helped him with his LS1 conversion. About the same time you started your project here, I started my own electric conversion on my Fiero (link to blog). I won't bore with non-delorean related details unless you ask, but Nick sent me a link to this thread to follow as I do mine. Basically I am looking for 100hp to power the front wheels while keeping an engine in the rear. I have decided to use the Leaf system because of this and the batteries. Obviously you're looking for a much higher output system on yours since it is the main drive. Have you seen what Jehu Garcia has done with his VW bus on youtube? Link to his youtube Electric samba here He basically built his own tesla battery packs for his DIY powerwall, and from the looks of the OEM packs he had in one video, they might fit very well in the front of the D.

I'm by no means an expert in any of this at all, but seeing as we are trying to do similar things, if you have anything you want to bounce off me, PM me.

I really look forward to seeing this happen!