# eBIMMER: Nissan Leaf into E30 BMW Conversion



## eBIMMER (Feb 28, 2020)

I spent most of my efforts over the last 2 weeks designing what I thought would be a good motor coupler and motor adapter. The waterjet house I used (NoCo Waterjet in Colorado) got my adapter plate turned around in 2 days. 2 Days! Better yet, my measurements appear to have been pretty decent because it lined up perfectly to all of the holes on the Nissan Leaf Gearbox.

This is probably a little over engineered but this will involve cutting irreplaceable parts of the Leaf drivetrain and I don't want to have to revisit this anytime in the future or buy back the parts if I biff these.

Using half of the gearbox allows me to use one of those massive Nissan gearbox bearings in a housing designed to mate perfectly with the motor. I hope this will offer the support and rigidity that is needed to isolate the motor from everything downstream. There is a an oil seal in my design so that I can flood the gearbox with oil and keep that bearing lubed.

There is misinformation out there saying these gearboxes use a pump and which would prevent them from safely running in reverse. That is not true, it is splash lubricated and I don't think anything would be damaged running it in reverse.

I'm at a holding point with the Leaf assembly that has put a temporary hold on the motor coupler (see next post) just because I don't want to spend more money on parts until I can get the Leaf system spinning. I'm also waiting to get a few machined parts back. I called in favors on cost so need to stay slack on timelines


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## eBIMMER (Feb 28, 2020)

Finally the part where I need the expert help of the kind folks on this forum!

I've got my Nissan Leaf system out of the car. It's set up on a sort of fixture of Unistrut and plywood to give me decent access to everything. It fires up and by plugging most things in, the DTCs are reasonably minimal. I'll eventually remove a bunch of crap but I wanted to start in a good place so I knew what I was trimming out.

I should say I'm using Leaf Spy Pro and that none of this would be possible without it. Hats Off to those good people!

Unfortunately the first time I went to fire the system up, the Parking Actuator was removed from the Gearbox and at some point during startup I heard it rotate an unknown amount and eventually stop. The full DTC list is posted as an attachment but the important ones (I think) are listed below:


B2603 0009 BCM SHIFT POSITION SEC-79
C1A70 0109 BRAKE BRAKE CONTROL SYSTEM BR-160
P318A 00C0 EV/HEV ELEC SHIFT SYSTEM EVC-252
U1000 00C0 EV/HEV CAN COMM CIRCUIT
P31B7 00C0 EV/HEV CAN ERROR EVC-285
P189F 000A SHIFT
P18A0 000A SHIFT

If I start thru the DTCs using the Nissan priority list, troubleshooting goes something like this: Check VCM. Restart. Check VCM. Replace VCM. I don't think that's my problem...

Specifically, P189F and P18AO refer to Angle Sensor 1 and Angle Sensor 2 and I believe them to be in the Parking Actuator which is attached to the gearbox. I've read in forums and the service manual that any time this is removed you need to use Consult 3+ to reset the zero value of the angle sensors. Can anyone shed more light on this for me? I understand these to be Hall Effect Sensors.  The parking linkage has 2 positions. The mate between actuator and shaft has 2 possible orientations. Unless these hall effect sensors can count multiple revolutions as opposed to location in a single revolution, or they're super duper sensitive, there should only be 4 possible combinations of Actuator clocking on shaft, right? Right?

Anywho being as most other DTCs relate to shift issues (P31B7 is airbag related, fyi) I think that is the big problem that keeps me from getting into gear and keeps a big red cog on the instrument display. Each time I try and get into gear the Leaf gives me a nice little double beep and the shift indicator on the center console has no lights illuminated.

Can anyone suggest ways around this parking actuator and/or how to reset the Actuator location without Consult 3+? I'm trying to establish a dialogue with the local Nissan dealer to see if somebody would make a house call to reset the value but that seems...unlikely.


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## Tremelune (Dec 8, 2009)

I think you're on the right track, but I have no answers beyond that. I believe it wants to see a water pump in the system, and you mentioned that got smashed.

It might be worth asking in the Leaf forum...There are at least a few people with intimate knowledge of the CAN stuff. There's a subforum dedicated to this kind of thing. It gets less traffic than the other subforums, but it's traffic from the right people, I imagine:

https://www.mynissanleaf.com/viewforum.php?f=8&sid=f146b2dbe76c10df62f3856de801888a


Why bother with the Leaf gearbox? Mated directly to the Getrag transmission (which would be simpler, I think), the motor'll spin the tires in 2nd and the top speed in 5th would be well over 90mph. You could then sell the Leaf gearbox to recoup costs.


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## eBIMMER (Feb 28, 2020)

Tremelune said:


> Why bother with the Leaf gearbox? Mated directly to the Getrag transmission (which would be simpler, I think), the motor'll spin the tires in 2nd and the top speed in 5th would be well over 90mph. You could then sell the Leaf gearbox to recoup costs.


Thanks for the reply Tremelune! The thought process that led me to using half of the gearbox started basically because I didn't want to connect the motor directly to the transmission without a clutch for the sake of the gearbox's syncros. I felt the flywheel required a big sturdy bearing for support and locating, and the half-gearbox design fit the bill for a perfectly on-center bearing housing which also provides a standoff distance so that the Leaf motor spindle doesn't need to get modified.

I know many folks do not use the clutch and go direct drive to the transmission. I suppose we'll see how this idea turns out. I think the convenience of perfect mounting interfaces outweighs the extra cash I'd get for selling it. In fact I'd probably keep the gearbox for another project if I didn't use it anyway


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## Tremelune (Dec 8, 2009)

Whatever works! Just be aware that with the gearing of the gearbox, you'll have the potential to push something like *1600 ft-lb of torque* into the BMW transmission. Full current would blow it up for sure. Check my math/understanding on this, but I think it will also limit the "output" of the Leaf gearbox to about 1250rpm (not 10k).


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## eBIMMER (Feb 28, 2020)

Tremelune said:


> Whatever works! Just be aware that with the gearing of the gearbox, you'll have the potential to push something like *1600 ft-lb of torque* into the BMW transmission. Full current would blow it up for sure. Check my math/understanding on this, but I think it will also limit the "output" of the Leaf gearbox to about 1250rpm (not 10k).


Oh, sorry I was not being clear in my description! I'm not using the Nissan gear box for it's reduction, I'm using it only to support the transaxle on it's way from motor output to the transmission. It's basically serving as a bearing housing and spacer. I hope that clarifies!

On the other hand I COULD drop the gear ratio and either climb walls with the car or vaporize the transmission internals


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## brian_ (Feb 7, 2017)

I realize that this thread hasn't been active for months, but I just read it because of eBIMMER's post on another thread.



eBIMMER said:


> The thought process that led me to using half of the gearbox started basically because I didn't want to connect the motor directly to the transmission without a clutch for the sake of the gearbox's syncros. I felt the flywheel required a big sturdy bearing for support and locating, and the half-gearbox design fit the bill for a perfectly on-center bearing housing which also provides a standoff distance so that the Leaf motor spindle doesn't need to get modified.


That all makes sense. I'll just make two notes:

The problem of synchro wear during shifting with a motor directly coupled (no clutch) to the transmission would be reduced or eliminated with proper control of the motor, to match the input shaft speed to that required for the target gear at the current road speed... and because production EVs generally don't use multi-ratio transmissions, that's not a readily available control feature.
If you do incorporate a clutch, and need the flywheel just as one side of the clutch assembly, you don't need any flywheel inertia; that means you can reduce bearing load by cutting off most of the mass of the flywheel (and certainly omitting the starter ring gear).


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## Tremelune (Dec 8, 2009)

Is synchro wear really a concern when you're shifting a few times per drive, vs a few times per minute? I've also read that since electric motors have very little inertia, it doesn't pack as much of a wallop as an ICE engine...

Like, even in the worst case where you're regularly jamming the transmission into gear with a grind...it seems like that wear would take many thousands of miles to even register as a problem. It's really just "city gear" and "highway gear". Am I off base?


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## eBIMMER (Feb 28, 2020)

I think you're correct that a shift here and there is no big deal considering all the factors you mention.

I've done a few "experimental" clutchless shifts with my system and I can imagine that doing it a few times each day with care is probably no big deal. Practically it isn't even necessary since 3rd gear starts from a stop as well as most ICE cars and can run up near 90mph.

However, having felt the excitement of a first gear pull from a stop, I cant help but think about how to mash it into second super fast for a 0-60 time. 

I appreciate your notes on lightening the flywheel, since I bet that will make a big difference on acceleration.

Thanks!


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## eBIMMER (Feb 28, 2020)

Hi world, just logged back in and thought I'd post an update.

I've gotba couple hundred miles on the car as an EV and its a total blast to drive!

I am still working to digest the Leaf electrical harnesses, which are formidable, and am nearly done with it. The remaining bits are sitting where the passenger seat used to go for now while I build them into the dash.

Had some really enlightening experiences with the gear motor parking brake actuator and shift selector mechanism, in case anyone is interested.

Still running with Leaf ABS fuse pulled, which I think is why my regen is minimal, but the brakes work great and dont stutter.

I'll post some photos as I get a chance!


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## Tremelune (Dec 8, 2009)

Did you have any issues fooling the Leaf into thinking it was still in a Leaf or did the system more or less work when you put everything in? To my knowledge, you're the only person who has succeeded in getting a Leaf working in another chassis with no aftermarket electronics...That's a pretty big deal, considering it cuts the costs of EV conversion parts 2-3x!

300k mile E30 given a new lease on life. I love it.


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## gotham (May 26, 2019)

How did you resolve the parking brake issue?


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## brian_ (Feb 7, 2017)

Tremelune said:


> Is synchro wear really a concern when you're shifting a few times per drive, vs a few times per minute? I've also read that since electric motors have very little inertia, it doesn't pack as much of a wallop as an ICE engine...
> 
> Like, even in the worst case where you're regularly jamming the transmission into gear with a grind...it seems like that wear would take many thousands of miles to even register as a problem. It's really just "city gear" and "highway gear". Am I off base?


No, electric motors are great flywheels, unfortunately. Essentially no one tries to shift without disengaging the clutch to an engine, so assuming that you're not double-declutching the inertia of an engine is irrelevant to the synchros.

It will be very slow to shift with a motor connected directly (without a clutch), without overriding the baulk rings and grinding. If you do wait long enough, I agree that many fewer shifts might result in adequate synchro life... but if y do use the same two gears all of the time those two synchros would see just as much use, while the other gears go completely unused.


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## gotham (May 26, 2019)

This is an interesting question to me. It seems like with RPM sensors on the electric motor and the output shaft of the transmission the electric motor could be made to speed match which would make clutchless shifting possible.


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## brian_ (Feb 7, 2017)

gotham said:


> It seems like with RPM sensors on the electric motor and the output shaft of the transmission the electric motor could be made to speed match which would make clutchless shifting possible.


I agree... but I have yet to see anyone do it. You actually need the transmission output speed, an indication of which gear you are changing into, and programming to multiply the output shaft speed by the gear ratio to determine the target input shaft speed... and a controller programmed with a target speed function (not just target torque or power). With proper speed matching synchros would not be necessary, and simple dog clutches would work.


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## gotham (May 26, 2019)

My thought was that the controller would know the gear you are in because of the ratio of input to output speeds. If your input speed is in the top half of available RPM it assumes you want to shift up. If you had the speed sensors perhaps you could hack the throttle signal to speed match in a separate closed loop system. It does require hacking the throttle signal which could be somewhat dangerous.


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## brian_ (Feb 7, 2017)

gotham said:


> My thought was that the controller would know the gear you are in because of the ratio of input to output speeds.


Yes, that works.



gotham said:


> If your input speed is in the top half of available RPM it assumes you want to shift up.


That might be a safe assumption... depending on the driver. If not, the system would need a switch for the driver to use (perhaps a thumb rocker on the shift knob).



gotham said:


> If you had the speed sensors perhaps you could hack the throttle signal to speed match in a separate closed loop system. It does require hacking the throttle signal which could be somewhat dangerous.


I agree.... although it would be preferable to avoid the delay of two cascading control systems.


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## eBIMMER (Feb 28, 2020)

gotham said:


> How did you resolve the parking brake issue?


Hopefully my photos attach to this post. As I think was described in an earlier post, I am using the engine side of the gearbox housing but not the other half.

The parking actuator mounts to the half i didn't need, so I cut out the part which holds the actuator and just bolted it up in the motor compartment. Not a clean solution but it works...mostly.

This worked in theory but road vibrations would tend to wiggle the actuator out of the "drive" range, throw a SHIFT error and ultimately cause the system to stop powering the motor. Yep, gotta find a safe place to get off the road fast!

So my fix was to weld an 80/20 aluminum angle bracket to the parking actuator gear box chassis and then use two spring loaded ball end set screws, set into just the right position to kind of lock the gear actuator in the park or drive position.

This has eliminated the issue of the actuator creeping out of drive but it isn't a perfectly clean solution. Perhaps one day this whole module can be replaced by a CAN spoofer, but with 3 sensors in that module, this is the most easily achievable way to go.


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## eBIMMER (Feb 28, 2020)

gotham said:


> How did you resolve the parking brake issue?


...on the other hand if you're asking about the actual parking brake module which engages the brakes of the rear axle...I've sort of just learned to deal with it and move on.. I kept the whole motor and actuator assembly together and mounted it in the spare tire carrier in the trunk. It is screwed to a plywood base and restrained carefully so it doesn't move around.

To simulate the parking brakes I used threaded rod, washers, and nuts on the cable stop so that as the cable pulls toward the motor the threaded rods pick up tension and simulate the brake pads locking on the brake drum.

The parking motor uses tension sensors to ensure the parking cable is pulled tight.

The actual park brake lever still lives inside my car though it is really only needed when something else in the car causes me to have to turn it off with an error.. then I pull the lever and the system stops beeping.

There must be a more elegant way to handle this but in my opinion its a loose end for a day far in the future. Probably easiest to solve with a CAN spoofer since the system has several sensors and power inputs. I still have the capacitor bank in the truck as well.


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## matthew.stead (Jun 8, 2020)

@eBIMMER interestingly my 2014 Leaf had a manual park brake and I was able to completely remove all braking systems from the minimum system (including capacitor).


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## gotham (May 26, 2019)

Super helpful. Thanks. I was asking about the gearbox parking brake. If I understand correctly your setup allows the module to move between park and drive and has detents to keep it from vibrating out of position. The rear parking brake wasn't on my radar.


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## eBIMMER (Feb 28, 2020)

gotham said:


> Super helpful. Thanks. I was asking about the gearbox parking brake. If I understand correctly your setup allows the module to move between park and drive and has detents to keep it from vibrating out of position. The rear parking brake wasn't on my radar.


Yep that's correct. So far so good, haven't had it slip out of gear since those detents were installed!

Nissan reverted to a manual parking brake in 2013 or 2014, so it makes sense yours is different. The electric one is a pain in the butt!


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## daydriver (Jan 14, 2022)

This project is awesome. I have an e30 roller I would love to do this with. Was there a reason not to keep the clutch?


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## eBIMMER (Feb 28, 2020)

daydriver said:


> This project is awesome. I have an e30 roller I would love to do this with. Was there a reason not to keep the clutch?


I did not install the clutch due to time and complexity, back when I did the work. I did keep the parts because IMO this configuration really should have one and one day I plan to put it back in. The clutch requires excellent alignment to the motor, a good bearing and bearing supports, and a heavily modified flywheel (to reduce mass, but primarily to bolt onto Leaf motor driveshaft with axial centers being very close). I have the part drawings but didn't ever make them. Instead, it was way faster to just weld a motor coupler together which rigidly joins the Leaf motor output and BMW transmission input shafts. If you're curious, there is a particular Fiat clutch disc whose center splines are compatible with the Leaf motor. Weld that into a cylinder, with the center of your donor car's flavor of clutch disc, and you have yourself a rigid coupler. Quick, dirty, cheap.

The car drives great in 3rd gear, so I keep it there. Other gears have their time and place. Since I don't have a clutch, I only shift gears when stopped. First gear is fun to spin circles in a parking lot. Fifth gear is dangerously slow to start but pulls hard over 100mph. Like I said, 3rd gear is good off the line and will do 75mph. So it works as-is, but adding the clutch and linking these gears would make for a very fun experience across the whole speed/torque spectrum.


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## remy_martian (Feb 4, 2019)

Which Fiat's clutch disc works?


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## daydriver (Jan 14, 2022)

After some searching it looks like it’s a Fiat Multipla 1.6L. Nissan Leaf motor coupler

Thanks so much for the info your build has been so helpful. I am trying to convince my buddies that this is the way to go since the roller we have is pretty thrashed (former rally car) but has all the important things. I think it would be a wicked fun rally Ross car as an ev.


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## eBIMMER (Feb 28, 2020)

Here is the info I was able to copy out of my email. I purchased it online from Midwest Bayless Italian Imports

Clutch Disc 20-Spline 200mm / 22mm

Part number 4304548

I think you'll find pics and drawings earlier in the thread.

Good luck!

Sent from my SM-G960U using Tapatalk


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