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Greetings! I write from the interior mountains of British Columbia. I've owned a Nissan Leaf since 2014. It has >180,000 km on it now and has been 'retired' to town use by my wife. In addition, we sold our other gas car last year and bought a rear-wheel drive Model 3, so EV-only since December 2018.

It's been great, BUT, we recently moved out of town and now live about 100m in elevation above the highway and have a relatively long steep hill to climb. Now that the snow has arrived, we are sort of regretting not buying an AWD Model 3, or keeping the previous car and waiting until there was a small SUV that could replace it.

So, I've lately been joking to my wife that I'll put a lift kit in the Leaf and turn it into an AWD for her... then I thought maybe we actually COULD do that?!

So, I found your forum and here I am.

I had a quick search on MNL to see if anyone had converted their Leaf to an AWD, but that turned up basically nothing (just someone else from 2012 idling speculating on doing the same thing).

I was thinking of getting a scrapped Leaf motor and mounting it to drive the rear wheels in some fashion. I am reasonably mechanically inclined when presented with something to repair (eg. bicycles, installed an EV kit on my cargo bike), but my training is as an environmental engineer, not mechanical eng or technologist, nor machinist etc.

I can see a number of possible problems - I'm wondering if you think any of them are insurmountable?

1) I think the biggest issue would be mounting the motor and driving the rear wheels. Seems that most conversions are utilizing the existing drivetrain components to get the wheels to turn (mating to the transmission). Can I just steal the front CV/transaxle/Leaf motor and fab some parts to mount it and drive the wheels?

2) Interfacing into the existing throttle system etc to drive a controller for the rear motor

3) If I use the same input to a controller for each front and rear motor, am I going to have problems with differing wheel speeds between front and rear axle going around corners? Obviously solvable, since Tesla has done this, and so has Mitsubishi with the Outlander PHEV, and even Nissan with a custom AWD Leaf.
 

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1) I think the biggest issue would be mounting the motor and driving the rear wheels. Seems that most conversions are utilizing the existing drivetrain components to get the wheels to turn (mating to the transmission). Can I just steal the front CV/transaxle/Leaf motor and fab some parts to mount it and drive the wheels?
Yes... and it might make sense to use the subframe and suspension as well. I would look at other Nissan models for a rear suspension from an AWD which might be compatible with the Leaf shafts, but it's unlikely that the Leaf motor and transaxle will readily fit into any of them.

The Leaf doesn't have anything under the floor in the rear (obviously no fuel tank but no storage compartment or anything either) so there is space, but it's not very tall and the Leaf motor with inverter stacked on top is tall.

2) Interfacing into the existing throttle system etc to drive a controller for the rear motor
Presumably you would use a controller connected to the existing CAN bus and with an additional port to pass selected messages to the rear motor's controller.

3) If I use the same input to a controller for each front and rear motor, am I going to have problems with differing wheel speeds between front and rear axle going around corners?
Not inherently, because the accelerator pedal reading is treated as a torque or power request, not a specific speed.
 

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I think the problem of at least the driveway can be solved by backing up your driveway. Much better traction that way. https://www.youtube.com/watch?v=06NtqDMFGiM Unless you are skilled modifying a Leaf to 4WD is extremely ambitious.





Greetings! I write from the interior mountains of British Columbia. I've owned a Nissan Leaf since 2014. It has >180,000 km on it now and has been 'retired' to town use by my wife. In addition, we sold our other gas car last year and bought a rear-wheel drive Model 3, so EV-only since December 2018.

It's been great, BUT, we recently moved out of town and now live about 100m in elevation above the highway and have a relatively long steep hill to climb. Now that the snow has arrived, we are sort of regretting not buying an AWD Model 3, or keeping the previous car and waiting until there was a small SUV that could replace it.

So, I've lately been joking to my wife that I'll put a lift kit in the Leaf and turn it into an AWD for her... then I thought maybe we actually COULD do that?!

So, I found your forum and here I am.

I had a quick search on MNL to see if anyone had converted their Leaf to an AWD, but that turned up basically nothing (just someone else from 2012 idling speculating on doing the same thing).

I was thinking of getting a scrapped Leaf motor and mounting it to drive the rear wheels in some fashion. I am reasonably mechanically inclined when presented with something to repair (eg. bicycles, installed an EV kit on my cargo bike), but my training is as an environmental engineer, not mechanical eng or technologist, nor machinist etc.

I can see a number of possible problems - I'm wondering if you think any of them are insurmountable?

1) I think the biggest issue would be mounting the motor and driving the rear wheels. Seems that most conversions are utilizing the existing drivetrain components to get the wheels to turn (mating to the transmission). Can I just steal the front CV/transaxle/Leaf motor and fab some parts to mount it and drive the wheels?

2) Interfacing into the existing throttle system etc to drive a controller for the rear motor

3) If I use the same input to a controller for each front and rear motor, am I going to have problems with differing wheel speeds between front and rear axle going around corners? Obviously solvable, since Tesla has done this, and so has Mitsubishi with the Outlander PHEV, and even Nissan with a custom AWD Leaf.
 

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A scrap Prius, Lexus or Highlander rear MGR may fit right under your car without anything special, would just need to fab new beam mounts and a new attachment to the parking brake.
The MGR drive unit might fit, and would be sufficient, but it won't do any good if it isn't connected to the wheels... and the Leaf rear hubs are not set up for drive axles. By sheer luck, do the rear bearing units have drive splines and does the suspension arm leave clear access for a half-shaft? Even if the Leaf owner is this luck, custom shafts will be needed to mate the Toyota drive unit outputs to the Nissan hubs.
 

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A Prius AWD rear MGR is an integrated rear drive axle in the common FWD beam shape.

Only thing needed is a controller to run it and obviously wheel spacers and mounts to the suspension
The Prius up to the XW30 generation (ending with model year 2015) has the twist-beam rear suspension typical of the MC/NewMC platform and many other inexpensive FWD cars, including the Leaf; it does not have AWD available.

The XW50 generation of Prius (starting with model year 2016) is on the TNGA-C platform, and has a multi-link independent rear suspension; this is visible, although not really clear, in that image from that PriusChat thread. If you go to the PriusChat thread and click on the bar on top of the image to view it full-size, you can see the trailing control arm on each side, plus three lateral links per side (one upper, two lower, coil spring on one of the lower links)... with all of the lateral links mounting to a crossmember which is not shown (and which doesn't exist in the Leaf). You can get this image in higher resolution from Toyota's download page for this image. The suspension (without the drive unit, and with the crossmember in grey) is shown much more clearly in another image from Toyota. It would be a substantial project to mount this suspension (or any other multi-link suspension) in a Leaf, and the drive unit would need to be mounted to the car's structure as well, in a way which can withstand the drive torque.
The source at Toyota: Under the Hood of the All-new Toyota Prius

Trivia: Toyota insists on calling this suspension setup a "double wishbone", perhaps because the trailing arm on each side is a wishbone... but that's not at all what "double wishbone" means in automotive technology. Some marketing idiot started this many years ago when this design was used on a previous model, and it persists.

If you're thinking that the Prius has the drive unit mounted on a moving axle beam, like the differential in a live beam axle... no, the motor would be quite heavy for that, and that's not how any past or current electrically driven Toyota axle is built.
 
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