# Introducing our 1987 Porsche 924S EV Conversion



## DaviLightning (10 mo ago)

Very cool. I'm hoping my Mini will turn into a father-son project as well. He is only 13 now and just starting to be interested in cars. I like that you are able to 3D print parts to test fit them. Great idea!


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## Electric Land Cruiser (Dec 30, 2020)

First of all, awesome car and awesome project! The 924 with it's rear transaxle configuration is just screaming for a rear-mounted LEAF drivetrain and conversion. Use the 200hp LEAF inverter and really make it scream. Front mounted motor is a waste of space and potential IMO.

Of course you need to visit www.resolve-ev.com and check out the Resolve controller and the creator's own EV 924 if you haven't already seen it.


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## lordmundi (10 mo ago)

Electric Land Cruiser said:


> First of all, awesome car and awesome project! The 924 with it's rear transaxle configuration is just screaming for a rear-mounted LEAF drivetrain and conversion. Use the 200hp LEAF inverter and really make it scream. Front mounted motor is a waste of space and potential IMO.
> 
> Of course you need to visit www.resolve-ev.com and check out the Resolve controller and the creator's own EV 924 if you haven't already seen it.


great info. I haven't seen that video yet. I guess i just haven't considered doing it rear mounted but I certainly can. I guess i just need to figure out how one would go about attaching the motor to the rear wheels and where everything would be welded and whatnot. Since it seems so common to just replace the engine with a motor i just figured that was the easiest way to go.


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## Electric Land Cruiser (Dec 30, 2020)

lordmundi said:


> great info. I haven't seen that video yet. I guess i just haven't considered doing it rear mounted but I certainly can. I guess i just need to figure out how one would go about attaching the motor to the rear wheels and where everything would be welded and whatnot. Since it seems so common to just replace the engine with a motor i just figured that was the easiest way to go.


It's certainly more common but I think not as good. If you mount the Leaf drivetrain in the rear where the transaxle lives, then you just need to adapt the CV axles from one transmission to another. That is actually pretty simple in the big scheme of things.


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## lordmundi (10 mo ago)

Electric Land Cruiser said:


> It's certainly more common but I think not as good. If you mount the Leaf drivetrain in the rear where the transaxle lives, then you just need to adapt the CV axles from one transmission to another. That is actually pretty simple in the big scheme of things.


maybe i just need to "see" it. I've got two wheels coming out each side of the transaxle... and only one output on the motor... right?


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## Electric Land Cruiser (Dec 30, 2020)

lordmundi said:


> maybe i just need to "see" it. I've got two wheels coming out each side of the transaxle... and only one output on the motor... right?


Sort of. The LEAF has a FWD gearbox with a differential and CV axles just like a normal car. The electric motor is bolted to that, the inverter is bolted on top, and then the PDM is bolted on top of that. If you ditch the PDM then it is much shorter. It makes for a very compact drive unit, I'm guessing similar or maybe slightly larger than the Porsche transaxle.

So you replace the transxle with two axles with the LEAF motor+gearbox with two axles.

Check out @windraver's thread for a bunch of photos. He is building a FWD Honda but the same principals apply to using it as a RWD: 1986 CRX EV conversion (Nissan Leaf Donor) - In Progress


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## Akh891 (9 mo ago)

lordmundi said:


> I've been lurking on the threads for quite a while but want to introduce our father-son EV conversion project on our 1987 Porsche 924S (which my son has affectionately named "Perl"). We are super excited to make steady progress toward our 80's inspired EV conversion.
> View attachment 128877
> 
> I am not a Porsche guy, so I have been surprised by just how much I've enjoyed learning about the Porsche 924 and 944 and their history, not to mention the community around them and just how much people love them, warts and all.
> ...


This project is very exciting, please keep us updated on it. I would recommend you take videos of your project and post it on YouTube both for memories and for us to enjoy what you are doing. Good Luck!!!


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## lordmundi (10 mo ago)

Akh891 said:


> This project is very exciting, please keep us updated on it. I would recommend you take videos of your project and post it on YouTube both for memories and for us to enjoy what you are doing. Good Luck!!!


absolutely... we've been taking some short videos as journals and will be putting them on youtube soon. I'll be sure to post notifications in this thread as well!


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## lordmundi (10 mo ago)

Our first video in our father-son EV conversion series is now out:


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## DansEVhobby (Jun 13, 2021)

watch out for excess battery heat if you go for the 110kw inverter unless you fit the newer and higher amp leaf battery pack in it as well. I just learned that a 110kw inverter and 350v pack takes about 315 peak amps which would melt a 24kwh battery pack (I assume).


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## lordmundi (10 mo ago)

DansEVhobby said:


> watch out for excess battery heat if you go for the 110kw inverter unless you fit the newer and higher amp leaf battery pack in it as well. I just learned that a 110kw inverter and 350v pack takes about 315 peak amps which would melt a 24kwh battery pack (I assume).


thanks. I'm not sure I understand everything you are saying. But right now we are planning to use the Nissan inverter that came with the leaf motor.. i believe both were from the same vehicle which i think was a 2015 Nissan Leaf. Is that still a concern?


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## remy_martian (Feb 4, 2019)

When you say "I just learned", please cite your source. The context and credibility of such expensive remarks by a third party need to be assessed.

thanks


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## DansEVhobby (Jun 13, 2021)

lordmundi said:


> thanks. I'm not sure I understand everything you are saying. But right now we are planning to use the Nissan inverter that came with the leaf motor.. i believe both were from the same vehicle which i think was a 2015 Nissan Leaf. Is that still a concern?


that would be the 80kw inverter then since they upgraded them to 110kw in 2017 along with a 40kwh pack and 60 optional pack. the 80kw had the 24kwh battery pack so those work together. the 80 seems like a good choice to me though unless you can afford such an expensive 40kwh+ pack to mate with the 110kw inverter.


remy_martian said:


> When you say "I just learned", please cite your source. The context and credibility of such expensive remarks by a third party need to be assessed.
> 
> thanks


That's according to the leaf wiki that they upgraded the packs when they upgraded the inverter. I'm not trying to throw out any false info I just thought it was a definite that the high watt inverter would be pulling more current than a used 24kwh pack would be intended for and would lead to hotter temps and even faster degradation.


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## lordmundi (10 mo ago)

part 2 is up:


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## lordmundi (10 mo ago)

Part 3 of our Porsche 924S EV conversion series is up:


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## lordmundi (10 mo ago)

Part 4 of our father-son Porsche 924S EV conversion project:


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## remy_martian (Feb 4, 2019)

I think it would be good to have a written summary with each posting that provokes watching the video.


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## SimonRafferty (Apr 13, 2009)

Perfect car to convert IMHO - and a great project too.
I wish you both the best of success.

Si


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## brian_ (Feb 7, 2017)

DansEVhobby said:


> watch out for excess battery heat if you go for the 110kw inverter unless you fit the newer and higher amp leaf battery pack in it as well. I just learned that a 110kw inverter and 350v pack takes about 315 peak amps which would melt a 24kwh battery pack (I assume).


110 kW divided by 350 V (which is less than half charged for Leaf battery, but that's a realistic scenario) is indeed 110,00/350=314 A. Yes, 350 kW / 24 kWh is 14.6/h, or a discharge rate of almost 15C, which is very high, especially for Leaf components. In stock form, Nissan limits all Leaf batteries to around 3 C:
80 kW / 24 kWh = 3.3 C
80 kW / 32 kWh = 2.5 C
110 kW / 40 kWh = 2.75 C
160 kW / 62 kWh = 2.6 C


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## blackterminal (Oct 14, 2021)

I vote to keep your driveshaft and mate your Leaf Motor to your existing gearbox. Keeps the car more original, keeps a gear shifter you might enjoy shifting whether you need to shift it much or not.


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## lordmundi (10 mo ago)

blackterminal said:


> I vote to keep your driveshaft and mate your Leaf Motor to your existing gearbox. Keeps the car more original, keeps a gear shifter you might enjoy shifting whether you need to shift it much or not.


well, we thought about this but the main support member for the front end axle runs almost in parallel with the drive shaft, and the motors I investigated would interfere with it. Which would require us to either offset the motor, or somehow shorten the drive shaft to move the motor further back into the middle of the car. Given that the leaf gearbox already has a differential, it seemed like maybe less work and a more direct solution to just hook it up to the rear wheels directly... not to mention all the weight we save from the big transmission and the torque tube and drive shaft. That's just our current thinking though.


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## lordmundi (10 mo ago)

Father-son Porsche 924S EV Conversion Part 5

More problems and frustrations with LED flashers and LED blinker bulbs. Let us know if you have any ideas! Also we got our engine bay cleaned and we started rebuilding our front brakes. Charlie wanted to paint them red, so we got them primed with self-etching primer and then painted with Cherry Red color.


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## lordmundi (10 mo ago)

Father-son Porsche 924S EV Conversion Part 6

In part 6 we eventually figure out a method to remove the transaxle from the Porsche. We eventually realized we needed a special "triple-square" bit to separate the axles and were able to get through that challenge. After the transaxle was removed, we completed the front brake rebuild including new rotors and Charlie's pretty red painted calipers. Lastly we showed off some new Nissan Leaf parts that arrived. Oh, and Charlie's new video intro and outro!! Full project playlist: https://www.youtube.com/playlist?list=PLnMVTS2-3X_C_09iLgKw9IFBuqwSWlXQ3


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## murat_jumash (5 mo ago)

@lordmundi great project! I wish I had enough time and money to work on a similar project with my 14 y.o. son.
I think it's gonna be valuable for you to check out this project: https://youtube.com/playlist?list=PLRAbBvvHWdlKqTgyUZbSfx-7iv5cn3Jxa They mounted Leaf stack directly to a Porsche's rear wheels.


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## lordmundi (10 mo ago)

murat_jumash said:


> @lordmundi great project! I wish I had enough time and money to work on a similar project with my 14 y.o. son.
> I think it's gonna be valuable for you to check out this project: https://youtube.com/playlist?list=PLRAbBvvHWdlKqTgyUZbSfx-7iv5cn3Jxa They mounted Leaf stack directly to a Porsche's rear wheels.


thanks so much! Yeah, we have watched quite a few of Shane's videos. There is a lot of great inspiration out there.


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## lordmundi (10 mo ago)

Father-son Porsche 924S EV Conversion Part 7 - Nissan Leaf motor spins for the first time!

This was a big milestone for us. We paused on some of the work under the car and started focusing on setting up our bench-top test environment. We had to get a bit creative since we didn't have a battery pack yet, and while we were waiting on parts we tried to 3d print various platforms to mount components to. But the big moment was when everything came together to finally let the Nissan Leaf motor spin for the very first time! Full project playlist: https://www.youtube.com/playlist?list=PLnMVTS2-3X_C_09iLgKw9IFBuqwSWlXQ3


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## SimonRafferty (Apr 13, 2009)

Nice video.
I'm just about the same stage - almost ready to power everything up & see what happens! I decided to do it tomorrow - not feeling brave enough today 🙂


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## Zieg (10 mo ago)

That's a great test bench! The keyed e-stop is a pretty cool idea too.


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## lordmundi (10 mo ago)

Father-son Porsche 924S EV Conversion Part 8 - Thunderstruck/Leaf bench test setup and walkthrough 

Some of our previous videos featured the benchtop test setup we are using to try and get components working before mounting them in the car. This video walks through that test setup along with our motivations for why/how we did things. Hopefully it is helpful to someone else.


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## lordmundi (10 mo ago)

Father-son Porsche 924S EV Conversion Part 9 - Mounting Nissan Leaf Gearbox and Releasing Parking Brake 

In this video we discuss getting the gearbox from the Nissan Leaf mounted to the motor and our journey to figure out how to release the parking brake/pawl in the gearbox. We managed to finally get the parking pawl to release after 3d printing a few different "wrenches" of sorts to turn the shaft. Right now the plan is to not use the parking brake in the transmission at all and instead just use the hand-brake, but we may revisit this later.


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## lordmundi (10 mo ago)

For anyone following this build - we are trying to find the high-voltage connector used with the Chevy Volt battery pack... I posted a thread about it here: Need help finding the high voltage battery connector for...

If you can help us find that connector/cable that would be much appreciated!


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## lordmundi (10 mo ago)

A slight side-project we have going - a little ESP32/Arduino display to show CAN bus data using IMgui display framework. Currently uses an ESP32-WROOM-32D and a MCP2515 CAN bus interface module. But, we are having issues with it occasionally resetting or sometimes locking up. I can't tell if it is a problem in one of the libraries I'm using or if it is a power/glitch issue. Anyhow, I'm trying not to focus on it too much since we have bigger fish to fry. But it is still fun to think about and experiment with.


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## Zieg (10 mo ago)

Um, any chance you'd be willing/able to measure those gearbox-to-engine bolts? Need to order one size longer to mount a brace under the head..


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## lordmundi (10 mo ago)

Zieg said:


> Um, any chance you'd be willing/able to measure those gearbox-to-engine bolts? Need to order one size longer to mount a brace under the head..


yeah absolutely. do you just want the length? I can take pictures of whatever you like... i've got the part numbers for those two (assuming I found the right ones).


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## Zieg (10 mo ago)

Yeah length from underside of the head to the end would be awesome, thank you. From measuring the motor I have figured out that they are M10x1.5 but not sure about length. Guessing about 60mm? Just want to see if I can confirm before going out hunting for more.


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## lordmundi (10 mo ago)

Zieg said:


> Yeah length from underside of the head to the end would be awesome, thank you. From measuring the motor I have figured out that they are M10x1.5 but not sure about length. Guessing about 60mm? Just want to see if I can confirm before going out hunting for more.


Looks like from the underside of the head to the end is about 65 mm. About 5 mm of that is the unthreaded tip. See pictures below. Also be aware, I think these bolts are aluminum. I'm not sure if there is any concern for dissimilar metals here, but just thought I would let you know. Pictures:

















Hope that helps!


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## Zieg (10 mo ago)

That's perfect, thank you so much! 

Good point about dissimilar metals, will have to look into that as well, I suppose. Much appreciated!


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## brian_ (Feb 7, 2017)

lordmundi said:


> ... Also be aware, I think these bolts are aluminum. I'm not sure if there is any concern for dissimilar metals here, but just thought I would let you know. Pictures:
> 
> View attachment 134808


It's extremely unlikely that any bolt is aluminum, and those don't appear to be. They're coated.

They're also tension (not shear) bolts, suggesting that alignment depends on dowels or other features of the cases. And they have flanged heads, suggesting that a bolt without the flange would need a washer.


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## lordmundi (10 mo ago)

I hear you, but these bolts feel really light in the hand.


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## brian_ (Feb 7, 2017)

lordmundi said:


> I hear you, but these bolts feel really light in the hand.


Of course I could be mistaken, but an aluminum bolt seems really unlikely. They exist, but I've never heard of one in this sort of application. Are the bolts attracted to a magnet? An aluminum bolt would weigh one-third of a steel bolt of the same size.


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## lordmundi (10 mo ago)

brian_ said:


> Of course I could be mistaken, but an aluminum bolt seems really unlikely. They exist, but I've never heard of one in this sort of application. Are the bolts attracted to a magnet? An aluminum bolt would weigh one-third of a steel bolt of the same size.


I just went out and checked and it is attracted to a magnet, so you are right. I'm not sure why it feels light to me. Thanks for keeping me straight!


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## floydr (Jun 21, 2021)

Could it be a titanium steel alloy bolt?
later floyd


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## lordmundi (10 mo ago)

floydr said:


> Could it be a titanium steel alloy bolt?
> later floyd


maybe... or i might just be dumb. the latter seems way more likely.


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## Zieg (10 mo ago)

I do have some of the bolts that hold the motor mount to the gearbox housing, took a closer look at them just now. They are larger diameter and shorter in length, but they also thread into aluminum. They are magnetic, and have grade 10.9 stamped into the head. They are also coated with something that looks friggin' exactly like the aluminum castings. Hot dip maybe? What I may do is order 2 bolts a bit longer for a bracket, and hit the junkyard to zip the other 4 bolts out of some other cars. Looks like they are common on a ton of other models (Sentra, Versa, Altima etc).

And for anyone in Canada, the damn things are $9/ea at the dealerships up here, but I bet these would be a good replacement:


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## floydr (Jun 21, 2021)

lordmundi said:


> the latter seems way more likely.


Doubt that.
later floyd


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## remy_martian (Feb 4, 2019)

Likely zinc plated


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## brian_ (Feb 7, 2017)

Zieg said:


> They are also coated with something that looks friggin' exactly like the aluminum castings. Hot dip maybe?


Likely one of several types of zinc coating (including zinc phosphate), one of which is hot-dip galvanized. Some suitable coating is likely important because of the installation into aluminum.


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## serious_sam (Mar 1, 2017)

The coating is likely zinc flake. Like dacromet or geomet.


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