Nissan Leaf Powertrain Swap

[theunz]

As for the noise, kids on bicycles have been solving that for decades with playing cards and clothespins. Perhaps the wire wheel hubcaps fad of the 70’s and 80’s will make a comeback!
Cheaper than alloy rims too

[redroadster]

That Trans setup can't work well if at all
The EV hibreds I've kinda researched have a SUV type Trans gearing wise .( a .3-3 mph crawler gear to get it going which is critical )
Plus the 14" diam outside driven diff ring gears like fwds

[Gregs672000]

To me, adding noises would be the equivalent of all the fake, non-functional hood scoops that were put on some 80's era cars... I hated that, and was delighted to see the Roadster's is there for cooling and is very functional. I MIGHT be OK with some kind of turbine whine, but the sound of induction roar in an electric car would just irritate me.

[Cyclewrks]

I discussed doing this conversion with one of the Leaf engineers, a few years ago, when I was on the test driver staff. His thoughts on the transmission was to retain the Leaf transmission and put a fixed axle in one side of the transaxle so it fed all the output through the other side. Rest of the conversion would be pretty straight forward in his opinion though.

[Alvin]

Thanks for your comments Alvin, this is the kind of feedback and discussion I am looking for!
You are correct, this setup with the clutchless transmission would remove the need for the pedal.

Thanks for all the info and for documenting the journey! I'm still wrapping my head around the lack of a clutch since there is a high rpm output shaft running through a standard manual gearbox, but I can google it.

For brakes, I think the stock ones will be OK. I am not putting a high powered electric motor in as the power numbers are comparable to a SR20. Regenerative braking is very interesting; the motor acts in place of the brakes to recharge the batteries while decelerating. In many EVs you can 1 pedal drive as the regenerative braking can be set to be very aggressive.

I guess some testing will be the answer here. My thinking it even with modest hp, like an SR20 or U20 stock brakes are fine, but the instant torque delivery makes me feel like repeated sudden "bursts" would tax the stock brakes. Again, maybe I'm spoiled by the Tesla experience here. My feeling is that the regenerative braking is like solar...might as well use it!

In regards to engine noise, I will miss it - the Datsun will have terrible wind noise without an engine.

Honest feedback, I appreciate it. I think it comes down to what your personal usage will be, and what "experience" gives you satisfaction whenever you are driving.

Curious what weight math you've done with the removal of ICE, retention of transmission/rear end, addition of Leaf power unit and batteries.


YouTube/social media can be nuts with the EV swaps but this literally popped up on my Instagram feed, a Tesla-powered Mercury built by ICON:

https://petrolicious.com/articles/moder ... cury-coupe



I love how they've treated the "engine" bay...maybe you could do something similar make the Leaf unit look like an R16/U20...or not

[less frustrated]

I know this is just taking up space and I have no intention or money to do something like this for myself, but I am sure enjoying following this.

[redroadster]

That NYC apartment fire that injured 38 , weeks ago ,the cause determined it was a lithium ion battery exploding ...$200 mil settlement?

[drieseck]

Mpowers, simply fantastic, keep us posted. I have a 50K original mile wagon and contemplating the conversion (yes,i'll keep all the L-16/gas bits safely stored). As with you, my concern is not cutting anything irreversible and looking stock--and all Nissan. I began to pursure a Leaf drivetrain---- then was re-directed. A good friend here in Oregon is John Wayland: https://www.wired.com/2010/08/white-zom ... 4-seconds/

To those that don't know him, John is a "character," but he bleeds Datsun and is a Niagra Falls of EV information. (Beyond all the crazy sponsor stickers you can see his car(s) are 99.9% stock body, and (look at the build dates) he was doing these swaps before Musk was shaving). If helpful to you, I have his direct contact info. He's very approachable and (after trying to re-direct your Nissan faith) he'll trouble shoot your Leaf-build ---on-the-phone-----as if it was his. Be ready, he'll address every, every single detail you (& others here) have outlined: b-storage & type, charging, weight, cooling, longevity, transmission, simplicity, fire-danger, and under-the-hood looks. I'm not as far along as you as I'm up to my eyeballs in a U20 build and my wagon is waiting. Thanks for sharing. dave

[mojorising84]

Very cool project! I'm excited to see how things shape up.
Having worked on hybrid and electric vehicles in the past, I can say that implementing a brake activated energy recuperation strategy is not as straightforward as it seems. For safety sake it should be tied into the braking system in some way to keep control of the bias. This could be using a pressure sensor from the brakes in the control algorithm but you should probably have some fail safes in place which turns off the regen in case there's an issue. The absolute best would be to integrate an Electronic Braking System (hydraulically actuated brake by wire) which actually uses a small pump to pressurize the rear brakes. The ECU then decides whether to use the motor torque or braking torque to brake the wheels while always maintaining the correct bias. But there's a lot of programming and tuning needed to get it right. It would be further complicated with the transmission and any play in the drive line. Easiest way to add regen is to just add a paddle behind the wheel or program some "overrun" torque but that could compromise the drivability.
Regarding the transmission I personally would just ditch it. It's just another component that may fail. Actually just ditch the entire driveline and drop the emotor on the rear axle. This saves you the weight and complexity of the all those components.
Not sure if the batteries will fit under the body as someone else mentioned but it would be cool to see a roadster "skateboard" frame.
Cheers,
David

[mpowers]

Thank you everyone for all the replies and input! Its been a while since I have logged in, I will have to update you on my progress in more detail. My company transferred me to Japan to study things related to this very subject, so actual work on the car has had to pause until at least next summer. I had to rush a bit get the car stripped down to just the body and frame rolling chassis before I left. The frame is all painted and has some new suspension parts at least. Currently its at a coworkers shop getting body work and paint done while while I am away. I know its a bit risky to get the paint done now, but based on my current concept and measurements, I shouldn't have to modify the body or frame. Plus it conveniently fits my personal timeline and budget. When I return to my car I hopefully will have more knowledge on what it takes to make this kind of swap successful!

[Gregs672000]

Thanks for the update... enjoy your adventures in Japan! Lucky!

[Ralph]

Just curious ...any update on your progress?

[TurboRagtop]

Very cool project! I'm excited to see how things shape up.
Having worked on hybrid and electric vehicles in the past, I can say that implementing a brake activated energy recuperation strategy is not as straightforward as it seems. For safety sake it should be tied into the braking system in some way to keep control of the bias. This could be using a pressure sensor from the brakes in the control algorithm but you should probably have some fail safes in place which turns off the regen in case there's an issue. The absolute best would be to integrate an Electronic Braking System (hydraulically actuated brake by wire) which actually uses a small pump to pressurize the rear brakes. The ECU then decides whether to use the motor torque or braking torque to brake the wheels while always maintaining the correct bias. But there's a lot of programming and tuning needed to get it right. It would be further complicated with the transmission and any play in the drive line. Easiest way to add regen is to just add a paddle behind the wheel or program some "overrun" torque but that could compromise the drivability.
Regarding the transmission I personally would just ditch it. It's just another component that may fail. Actually just ditch the entire driveline and drop the emotor on the rear axle. This saves you the weight and complexity of the all those components.
Not sure if the batteries will fit under the body as someone else mentioned but it would be cool to see a roadster "skateboard" frame.
Cheers,
David

I was really enjoying your thoughtful post until you said “drop the E motor on the rear axle“
Mounting the e-motor on the rear differential would cause an unacceptable increase in unsprung weight, and ruin the handling of the vehicle. Mounting it to the frame, and using a belt or chain to drive the pinion shaft of the diff would be the way to go, but also full of challenges, as the rear axle moves up and down with reference to the frame. How would you solve that?
I don’t mean to come across as being critical, as a matter fact, I like your line of thinking. I’m just curious how the motor would power a pinion shaft that is constantly moving up and down and even a little bit side to side?
Don’t be offended, I am genuinely curious as to how this might work.

[mojorising84]

Apologies, didn't expand on my thought. It would certainly be best to run independent suspension at that point. Since everything else is being redone, you could mount everything to a subframe (motor, diff, suspension) and just bolt it to the regular frame of the vehicle. I think first Gen miatas use a subframe setup in the rear? Not entirely sure. One thing for sure though is eliminating as much backlash in the system as possible will only help.

[mojorising84]

Not sure what happened there... I managed to post that twice somehow? Not sure how to delete it as I posted from my phone.