wsrgklt

I looked at this a bit while putting together my rebuild comparison spreadsheet, and I think the short answer is no.

Assuming you want high performance (it's a Porsche, not a Prius) and a range of at least a couple hundred miles, I think you would have to spend at least 25k on the drivetrain, and maybe a lot more. Looking around the Ev West website, the high output motors are around $10-12k. Tesla battery packs are around $300/kWh, so you're looking at around $15k for something equivalent to the base Model 3 battery pack. That's all before adding regenerative braking, wiring, chassis mods and other stuff that I'm sure I'm ignorant of.

I may be looking at this all wrong - would love for someone with more knowledge to jump in.

mcgousha

You're right, performance and range will have a huge impact on costs. I could convert the car to electric using an old forklift motor and some lead acid batteries for a couple of grand... But that would be an embarrasment to the badge on the bonnet.

I'm using a leaf motor for my build to try to keep the costs somewhat reasonable and while the stock power of the leaft is about 1/3rd of the power from this era 911, the general consensus is thay Nissan are playing it ridiculously safe with this motor and that it can handle far more.

The biggest single outlay on this build is going to be the battery and i will probably build up the range iteratively as the funds are available. Then at some point it is going to reach a point where it is a trade off between increasing the range or keeping the weight reasonable.

wsrgklt

Heh, yeah I probably got a bit carried away with the Tesla parts list. Quick Google search shows complete Leaf motors for USD 2,500, and people talking about modifying them to 300hp, which would be in the same neighborhood as stock. That definitely changes the equation. Do you know what kind of batteries you're planning to use yet?

mcgousha

Batteries is still an open question. The Leaf ones come in "relatively" cheap per KWh, but I have heard there are limits to the amount of power they can deliver at a time. Which in turn would limit the performance potential of the motor. I have heard good things about Volt battery packs, but they didn't sell all that many this side of the Atlantic, so I have had to put some feelers out to see what I can get my hands on. The Tesla batteries deliver the biggest punch, but they are also very expensive.

It may end up being start off with with what I can get my hands on and then replace it if it doesn't give me what I want.

I'm currently trying to run the motor and inverter off lead acid batteries so anything will be an improvement on that:-)
Here's the current set up:

Capt. Obvious

What about TWO Leaf motors?

5CHN3LL

Check out EVWest and Batteryhookup.com - the folks at one or the other may be able to tell you where to source used Tesla battery modules closer to you...

mcgousha

Ha, I did consider that as a potential future upgrade, assuming I managed to successfully get one working. There would be some complexity in the software to ensure they are running in sync, but I figure I could turn this into a narrow body C4 by adding a second motor in the front. I'm sure there would be some obstacles to clear around steering components and the like as well.

mcgousha

Okay, so I realise I haven't really given much of a project update in a while, so here we go.

I'm still running the project as two stand alone streams, but we are getting closer to bringing them together.

With the car, most of the effort has been cosmetic on the car, this has mainly been to make space in the garage so I can put the car in there when it comes time to drop the engine. I have done a full interior swap on the car and I will probably post another thread around that, but there are some video's here if you are interested or need to see how it's done.


With the Motor the effort has mainly been around trying to get it running on the bench. I have the bench set up complete and have built a software controlled precharge circuit I can use, but I am struggling a bit with the CAN communication. While I continue to work through that, I will probably order a drop in board from the Open Source Inverter guys (which was going to be phase 2 anyway) so the project isn't held up.

mcgousha

While I am still trying to get the motor running standalone, I figured there was nothing stopping me from progressing a few other things in parallel. The most recent job has been to look at how the Leaf motor is going to fit into the Porsche, which is step one in bringing the two streams together.


From here we can start figuring out how to mount the motor into the space in the car where the transmission currently lives.

mcgousha

Wow, has it really been two months since I last posted an update on this project? Time flies when you are having fun.

I hit a pretty big milestone a few weeks ago when I dropped the engine from the Porsche and finally got a proper look at the space I have to work with.

The job itself was a much bigger undertaking than I had originally thought, while it is possible to drop the engine in a home garage with the normal tools a enthusiast would have, it does add to the time it takes to do the job. It would definitely have been easier if I had access to a lift rather than just jack stands. I reckon in total it probably took me 15 hours over 3 days to do the job.

mcgousha

If anyone is interested, you can see the step by step of the job here:

And the aftermath here:

pdxmotorhead

Google Truckla, its a Model 3 converted to a pickup, there is a guy who specializes in the tesla power and controls..
His shop might be a good source..

mcgousha

Just wanted to give an update on this as it's been a few months since I last posted. I've ended up spending most of my limited free time working on the project so I have been making progress.

I'm taking an agile approach to this, trying to get things in place and working in some way, shape or form so I can get this car moving, with the view that I can redo some of the work at a later date to make things more permanent, stronger, or just better.

I spent a good few weeks trying to figure out the best layout and orientation for the motor, and ended up having to take a cutoff wheel to part of the motor casing to allow it to fit. I decided to run the Leaf motor and gearbox together, rather than trying to run it through the existing tiptronic gearbox and ended up pivoting the leaf motor 180 degrees horizontally to make it fit in the space. The rear seat buckets encroached too much into the space where the gearbox was to make it possible any other way. This means I need to run the motor in reverse so I will need to add some sort of transmission fluid scavenge system to get the fluid to the right parts of the leaf gearbox, but that's a challenge for another week.

For the current set up, I created some brackets that I could mount the standard leaf motor mounting brackets to so we can hold the motor in place and test it, but in the longer term, I plan to combine the motor mounting into the batter box.

With the motor held in place, I was able to focus on starting to integrate the motor into the car, that meant looking at electrical connections and drive shafts. I built a custom loom to manage the various signals to the inverter and installed it in the car and I chopped and welded the four halfshafts I had (2 Nissan, 2 Porsche) to make 2 shafts with Porsche CV joints on the outside and Nissan Leaf CV joints on the inside.


Since then the effort has been to get the other components in place, mainly the inverter and precharge circuit and most recently to put in a bunch of small lead acid batteries to use as a test battery back.

With that all in place and now fully wired up, I am running out of ways to put off actually trying to run the motor in the car.
I am doing a complete check of the wiring now, but once that is done, I think my only option is to switch it all on, send power to the inverter, press the accelerator pedal and hope for the best.

I'll let you know how I get on, this is getting exciting.