LeafZX: EV + Literbike = DIY road coupled hybrid

[Derek]

I alluded to this in my 510 project thread -- I am starting a new project and am excited about it and will be sharing with you as I go along.

I can't be bothered to edit and post my project photos, so here's a google album that I just dump them all in: https://photos.app.goo.gl/hBUezQtiCVuvTPQ99

I've wanted a sport bike powered car for a long time (for the sound and sequential box), but the level of effort to build one is daunting and the actual end results seem mixed-- take a tiny vintage (no smog) car and hack it up (see SuperFastMatt on youtube for example), and then figure out how to get it to go backwards, and have your neighbors hate you when you slip the clutch to the moon to get rolling at every stop. I've also wanted to do something more technology focused and with my EV background a custom EV project seems like a no-brainer, but having built them professionally I know that they have a bunch of complications (and safety hazards) as well, and then there's the range issue of any car without an OEM sized battery pack which is hard to package in a car not designed for it (see any Bolt battery/Tesla drivetrain car -- the current DIY EV flavor du jour).

BUT -- how about we go one step further and combine those two things together and make a bike powered hybrid? Take a small AWD car (323 GTX, Civic wagon, Impreza) and electrify the front drive (I have some custom leftover motor-less Quaife EV transaxles from my Mission days), add in a small power-dense battery pack, register it as an EV conversion (no smog!) and throw a bike motor the rear. You get the sound and fury of sport bike motor with the torque, reverse and energy recapture from the EV drivetrain, but no range issues. Sounds a lot more complex, but I've never let complexity get in the way of a great/terrible idea (see my second Battlebot Pressure Drop). Thinking about it more, it seemed like a great long-term project for when I have lots of spare time. Did I mention I have two kids? Clearly this would have to wait until they're teenagers and don't want to spend any time with me. But this is a depressing thought, both regarding the kids and the fact my dream project can't be pursued for years.

While talking with an engineer friend of mine about this fantasy car project his suggestion was think about what you could do in a weekend with a group of friends -- focus on doing it as simply and quick as possible, keeping the design and fab tasks down. Treat it as a proof of concept before signing up for a massive long term project -- who knows, the whole thing could suck. Sound, sensible advice, that got me thinking about how to drive complexity out. So I've come up with this, and while it won't take a weekend, it has been distilled down enough to convince my wife that I can pull it off without abandoning our family or having her leave me:

Step one, forget about starting with a cool vintage platform. Instead start with a production FWD EV platform and keep 100% of the stock EV parts so you have a drivable car from the get go (with reverse, AC and all the modern other car stuff) and with no need for any EV engineering. Next, find a car that has space enough for a rear drive subframe from another car and the bike engine (with minimal mods) in the back (IE doesn't crash into the battery), and cross your fingers that they can be had cheap, since I'm just going to rune it with this Frankenstein project. Mix these parts together with some metal, machining and weld beads et voila -- proof of concept DIY road-coupled hybrid.

After gathering as much info as I could on the potential vehicles it was clear that a Gen1 Nissan Leaf was going to be my best bet -- and could be had cheap. Through info found on google image search, forums and service manuals, I determined with CAD assisted overlays of photographs that there was likely enough space for a Gen2 Lexus IS rear subframe in the rear, which has a similar (slightly more narrow track width), a small mounting footprint and the same wheel bolt pattern. With the EV drive providing off the line torque, there no need for a big bore Hayabusa or ZX1400 (which along with being $$$ suffer from oiling issues without a dry sump anyway), and modern 1000cc bikes make nearly as much power. GrabCAD had a *chef-kiss* perfect CAD of a CBR954RR engine that I used to get a feel for how a liter bike engine and chain drive might package in the hatch of the Leaf. I also spent a bunch of timing thinking of system level issues -- how to make it all work together, and what could be simplified or pushed to a later date after just getting the whole thing working. I also found a deadline -- Autopia 2099 https://www.instagram.com/autopia2099/ -- an EV car show organized by Bradley Brownell who was one of the people behind Radwood -- who is ALSO building a DIY road coupled hybrid, (a Boxster with a leaf front drive). I do love a deadline and the idea of driving a sport bike powered Leaf down to LA to roll into this EV gathering felt too perfect.

After watching all the usual spots (CL, Barf, Copart) for cheap liter bikes for a month or so, I finally came across an unfinished project 2009 Kawasaki ZX10R -- lacking body work, having backed DMV fees and a clutch that was stuck engaged, I seized the moment bought it over the phone for $2200 while on vacation in Hawaii. The day I got back I towed it home from Sacramento to SF in a uhaul trailer behind my TSX wagon. After getting the clutch back in order, I proceeded to disassemble the engine to release it from the frame. The whole package is so tiny and cute. My wife helped me do the final release from the bike and lift it onto a dolly without much effort. The tech is also amazing -- two layers of ITBs, 8 fuel injectors, full titanium exhaust, insanely tight packaging. Goes to show how much of the cost of a car is wrapped up in doors, interior etc. You get rid of all this crap and suddenly you can have an engine that can make 200hp/liter.

I have now taken photos and measurements and am getting the engine into CAD to design motor mounts and the chain line assembly. Looking at FSAE projects for inspiration here, except those kids put too much effort and analysis in for my tastes (IE I'm not going to that trouble in my free time), so I'm also looking to circle track tech -- certain classes run 1000cc motors and have VERY straight forward motor cradle designs. In any case, I plan to just over build. This car is going to be a pig (probably 3800lbs), so I'm not going to be a weight weenie -- as running endless FEA studies and optimizing is counter to my project ethos (remember: fast, simple, proof of concept).

I also found a Leaf -- a minty 2013 SV with 38k miles and a battery with a sad 60% State of Health (but 9 "bars" on the battery meter), which led to the reasonable price of $5k. I had my friend Mike (who is helping me with this project) drive me down to Santa Cruz to get it, after which I hypermiled it over 17 to get to a charging station on the other side of the hill to charge to 100% (about 40 miles) to make it back to SF. 2011 and 2012s could be had cheaper but they have their chargers right behind the rear seats and relocating a water cooled EV charger wasn't about to end up in in my already lengthy to-do list. I immediately stripped the rear seats and trunk interior out, and removed the rear under tray making it much sportier (with only 2 seats) and adding greatly to NVH. Next steps are to get it up on jack stands and take measurements to get it into CAD.

Another purchase I made to avoid fabrication was splashing out on a $1400 sealed Quaife LSDs designed for chain drive (typically used in FSAE or DSR) from https://www.taylor-race.com/ which should arrive in a couple of weeks.

In the next few days I'll be picking up a complete (minus differential) Gen2 Lexus IS rear subframe from a wrecker, for $600 for the whole thing disc to disc minus the diff, which I don't need.

I've also bought a bunch of mechanical components to build a shifter and clutch pedal, and electronics (Arduino of course) to interface with the Leaf throttle pedal (which will send signals to a servo running the bike throttle, and signals up to the Leaf controller) and have worked out modes and theory of operation.

The first major milestone will be getting the engine and driveline built up on the subframe. I plan to have it all running as a bread-board of sorts before it goes into the car. After that it's the heavy lifting of hacking the unibody and figuring out how to combine the new subframe. In the midst is figuring out exhaust and cooling and axles and fuel and a bunch of other problems I don't even know about. But that's all part of the fun, right?

In summary this project combines all sorts of things I love -- sport bike powered cars, EVs, twin motor AWD setups, rolling science projects, and weird ass shit no one else has done.

More to come!

[icehouse]

Dang we just sold our old 2013 Leaf only down one battery bar in mint condition for 2500 bucks to a friend! I would have way rather had it go to a cool project. We got the 2020 Leaf now. Which is way faster 0-60 I think with better tires it would be even faster. It just lays rubber haha. Wonder if you could swap the motor into the old Leaf? That with a rear engine would really zing.

[Derek]

Oh man that would have been a good deal. I probably could have found one better and/or cheaper, but I'm impatient and wanted to get started ASAP. As for performance, I'll worry more about that once its running. Ideally all this stuff would be transplanted into a different body with a smaller pack at some point, but trying to keep it simple you know! There's a big community of Leaf hackers and PCBs can be swapped in the motor controller to unlock a bunch more power, but that comes with its own complications.

I've had 4 EVs now -- a Focus EV, a Chevy Bolt, a Fiat 500e (which I still have) and now this Leaf. I would have like to have used the 500e which is cooler and much faster, but a large part of the battery is in the trunk. The Bolt would be great (as it's MUCH faster, and battery ends at the rear seat), but they're too much $$ to hack up just yet.

I'll figure out a work flow to get photos and updates in here soon! Taking measurements from the Leaf tonight to get it in CAD to help position the engine.

[DADZSUN]

Cool project! I'm thinking of a similar hybrid setup on my frankenstein Datsun 620 pickup. It's 'adopted' a G35x AWD platform and Phase 1 is to first run in RDW configuration.

With the G35x front subframe/suspension/uprights, there is room to run a set of front axles. My goal was to explore a hybrid setup with a couple of pancake motors within the engine bay and as much as 10kwh batteries stored within the ample space under the rear of the truck's bed. Added bonus would be that it will likely help with overall chassis balance.

Recently, I've kind of moved away from that idea because I see all too often at work the effects of transportation LiOn battery failure. Also, a custom battery management system alone makes me nervous. I may wait a bit as super capacitor and/or solid state batteries do show promise and potentially safer energy storage.

Of note, I recently had a chance to closely examine a Hyundai Nexo hydrogen powered car and it was impressive! The whole concept of fuel cell/hydrogen as a means of energy provision in lieu of larger batteries seems very promising. Too bad fuel cells and hydrogen fuelling stations are still so rare.

[Derek]

Oh hey! I have not forgotten about this, but I've been so busy working on it that I haven't had time to post. While down in Las Vegas filming Battlebots I spent a handful of days in the downtime between judging fights to do CAD work using 3D scans I did earlier -- a whole other project inself! Everything got dialed last weekend and I just did all the major parts buying to get the engine systems together (cooling, exhaust, driveline, fuel) and parts are landing this week!

Check out my google photos album with all the details and annotated photos -- if you're interested in more frequent updates, join this album: https://photos.app.goo.gl/hBUezQtiCVuvTPQ99

Some highlights:

Bike wiring harness running on the bench -- making some simplifications and patching in where needed but trying to keep changes minimal.

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IS350 rear subframe coated in a splatter of cornstarch to help the Photogrammetry software feature match images.

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Scan of the underside of the Leaf I did on a friend's lift

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How it all fits together in a computer!

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Shifter is a 4 bar linkage to move the ball into the position I want without having to modify any of the underlying leaf stuff

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Only billet planned for the build (for now) to hold the differential carrier bearings. Custom 56T sprocket from PBI and sealed Quaife ATB

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[Derek]

Exciting times -- my major laser cut parts order from OSHCut landed yesterday and I got busying fitting things together. Today I should be pressing the differential bearings on and doing the first build of the driveline cradle which will support the engine and the chainline. I also couldn't resist building up the shifter mechanism (talk about cart before the horse!) and it went together well aside from the centering springs being a little on the weak side and making quite a bit of noise.

Next steps are doing all the drilling/tapping/post machining on these pieces, establishing the correct offset for the engine to get the chain-line straight. Once that's in order, I'll be finishing the design of all the parts that will get welded to the subframe to get the engine cradle installed.

Lots more photos on https://photos.app.goo.gl/hBUezQtiCVuvTPQ99

Laser cut parts for the drivetrain cradle

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OSHCut parts for the shifter and clutch assemblies

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Assembled Shifter

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[icehouse]

Did you just import the mesh into Solidworks?

[Derek]

Workflow is generally:

Take hundreds of photos
Meshroom crunches for 10s of hours
Open mesh in Meshlab to trim and simplify
Open in Solidworks as mesh graphic (not surfaces or solid)
Extract surfaces (usually two major parallel faces) from mesh (Solidworks 2018+ feature) for measuring (or measure in Meshlab)
Measure in SW to determine scale
Reopen in Meshlab to scale
Open in Solidworks, verify scaling, extract reference surfaces (planar and cylindrical) as desired, use these surfaces and sketches to create reference planes that aligns the scan correctly.
Insert into new assembly and align created planes to the basic front/right/top planes.

You now have a scaled and oriented part to work with!

Showing edges of a complex mesh will kill your computer, so turn those off and turn on "real view graphics" to be able to discern the shape of your mesh. Without real view they just appear as flat blobs.

[bertvorgon]

Coming from the days of a 4 barrel carburetor, a six pack of beer and a screw driver.... I find what you younger guys do now for "modern" hot rodding, adaption and electronics/ computers..... STAGGERING...I tip my helmet to you all.

[Derek]

Hah thanks Keith, yes this really is modern hot rodding. Not a lot of new cars you can do something so radical with while remaining emissions legal-ish.
I also appreciate being called "younger" (turning 44 in less than a month), but of course, I've known you since I was in my 20s. Where has the time gone?

[bertvorgon]

Just BLOWN by!!!!

I still watch Battlebots on occasion and I remember coming and seeing yours, when doing the East End Crawl that time.

Every time I shut the door on the Datsun I thank you for those nice inner door handles.

Our 510 Enduro Team was in 2006.....15 years ago.....Holy.....I guess really the beginning of your 510 project, then running the Targa in Newfoundland.

Most of our original local crowd I have 20-30 years on them, when I first met Noel K., the creator of the 510 Club of B.C., he was a teenager.

Yup...TIME...as I have slowly been organizing all my race stuff, I both cannot believe I did all that, and how did I get the TIME to do all of it. I do know for the early years...I lived at Specialty......

[funwithmonkeys]

I'm following this. I look forward to seeing how this turns out.
Did you work at white monkey with another Derek?

[Derek]

Keith -- good memories all around. Some of my old projects I feel the same way -- I don't know how I made all that stuff. The difference with this one is that I'm trying to do it with as little work as possible Outsourcing the bulk of the part fabrication makes a huge difference.

funwithmonkeys -- I did -- Derek Junck. I suppose you know him?

Getting lots done in the past couple of days -- assembled the engine cradle and diff carrier, made a prototype of the clutch pedal assembly and fit the shifter into the center console. Fun!

All of the photos, most of them annotated can be found in the album: https://photos.app.goo.gl/hBUezQtiCVuvTPQ99

Shifter in the car -- it bolts up!

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Pressing the bearings onto the Quaife ATB diff

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Shifter mechanism perfectly sneaking out of the change tray hole.

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Driveline & Engine cradle

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Chain Line View

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In place on the IS subframe with rear shear panels installed

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[Derek]

With the G35x front subframe/suspension/uprights, there is room to run a set of front axles. My goal was to explore a hybrid setup with a couple of pancake motors within the engine bay and as much as 10kwh batteries stored within the ample space under the rear of the truck's bed. Added bonus would be that it will likely help with overall chassis balance.

Recently, I've kind of moved away from that idea because I see all too often at work the effects of transportation LiOn battery failure. Also, a custom battery management system alone makes me nervous. I may wait a bit as super capacitor and/or solid state batteries do show promise and potentially safer energy storage.

DADZSUN -- apologies, I didn't see this message until now. Your project is wild enough without adding electrons! I hear you on the risks of DIY battery stuff. I've built EV systems now at work in a couple of different jobs and it's serious stuff and expensive to do right, which is why I'm not messing with anything battery related on this build. The ideal battery for this car (or any performance hybrid) at the moment would be the pack from an i8. There's a guy in Toronto who has built an amazing hybrid 350Z using this battery -- you may have heard of it: https://www.mountainpassperformance.com ... -overview/

[Derek]

510 Friends!

Yes it's been a while but between a family, a job and this project its only left me enough time to run just a photo dump of everything related to this project in lieu of posting, which can be found here: https://photos.app.goo.gl/hBUezQtiCVuvTPQ99

If you've been following along -- you'd know I am here:

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All functionally required systems are in the car -- and I drove it for the first time today under full hybrid power! I did a short 3 mile loop on a divided 4 lane road near my house, where I got into full throttle for the first time. I don't think I made it to redline (but def in the 10K+ rpm range) and I touched 70mph indicated. The power was great the sound was insane. Still lots to do -- getting air to the radiator, filling in the firewall, alignment, etc -- but today was a triumph for me in this project.

Air intake mocked up in the passenger rear window -- this will feed the radiator

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The hatch is heavily vented -- bit of a rally-cross feel to it.

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Interior has a simple switch panel along with a video feed of the bike gauge from the hatch

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