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1986 Honda CRX (EM57 2013 Leaf Motor)
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Discussion Starter · #1 · (Edited)
I'm new and am planning to convert my 1986 Honda CRX into an EV. I have a 2015 Fiat 500e for parts but from what I know so far, the Fiat is sensitive and difficult to use for parts. I believe it uses the Bosch 180/120 based on my Google fu. I've sourced the wiring diagram for the vehicle and confirmed it is indeed a 3 phase AC motor, one for each phase, 2 wires to sense temperature, and another 6 for the resolve (excitor, sin, cos). The biggest challenge is that Fiat uses canbus and the controller, inverter, battery, and more likely will not operate without all the parts. The car almost disabled itself when I changed the radio to android auto makes a good example. I am studying how canbus works in order to see if I can either ignore errors or maybe even hack the system to work.

As back up if I have to build from scratch, I have a separate thread pending approval where I'm asking about the compatibility of the Bosch SMG 180/120 with the Scott drive 250 AC controller.

Also I'm reading I might need an inverter? And what else? I'm still digging through the site trying to figure out what are all the parts needed to run an EV with an AC motor, which seems to be more complex and less popular than running DC. So guides or hints are welcome as I learn the anatomy of an EV.
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Edit (2021-12-06):
Current project is now to convert the 1986 Honda CRX using a 2013 Nissan Leaf as a donor car in combination with the Resolve-EV Controller.
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Edit (2021-12-23):
Project has begun; Battery Dropped; still need a machine shop to make parts.
 

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1996 Toyota Land Cruiser
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I love the CRX. I believe that the 500e has a similar powertrain to the Nissan LEAF. The battery is different but the motor and inverter I think are very similar. Possibly the Resolve-EV controller would work for you. If you can sniff the CAN Bus messages and send to Isak at Resolve he could probably confirm for you.

Otherwise I can't wait to see what you do. I had a 1987 HF Hatchback that I modified and used in autocross and other fun stuff and it weighed 1788lbs on the scale with a full tank of gas so you can't get much better than that. The CRX has lots of space for batteries too.

P.S. Louvers rule!
 

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1986 Honda CRX (EM57 2013 Leaf Motor)
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Discussion Starter · #4 ·
Ooo, good information! I'll research the motor in the leaf then. I do recall reading that the smart fortwo has the same motor so I'll take that into consideration as well.

I've ordered a usb2can so I'll be doing some canbus logging soon.
 

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You're already used to not going to the gas station too often. might as well drive right past it.

looking forward to this build. now we need a del sol and a crz to join this newb fest. :D
 

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1986 Honda CRX (EM57 2013 Leaf Motor)
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Discussion Starter · #9 ·
My bad, I planned to come back here once I had more content.

I did choose to go with Resolve EV and coupler but I have not figure out how to procure an adapter yet. I haven't gotten replies from my local machine shops via email so maybe I'll have to call them when I have a chance.

I'll post a better update in the near future. I haven't physically started the project fully as I'm still planning and procuring parts. Also wrapping up some other home projects related to electrical so this had to wait. Likely will start it up after mid December.

(also I didn't think anyone actually cared to follow this thread but I'll be sure to update it going forward)
 

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1986 Honda CRX (EM57 2013 Leaf Motor)
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Discussion Starter · #11 ·
So to update things on this side, within 1-2 weeks, I really should be able to begin some actual mechanical work.

Current project is to swap the 2013 Nissan Leaf into the 1986 Honda CRX Si while retaining the D15Z1 Civic VX Transmission. This transmission has long gears meant for high fuel economy so it should work rather well with the electric motor

As of now, the project plan is as follows:
1. Drop the Nissan Leaf Battery
2. Extract Nissan Leaf motor assembly
3. Extract other misc parts that might come in use later like AC assembly, Accelerator assembly, maybe wheel hubs assembly, axles, mounts, etc.
4. Roll the Leaf out of garage and bring in the CRX
5. Extract motor, fuel assembly, etc. Basically clear the way for the electrical build
5.5 Bench test Leaf Motor, Battery, controller, inverter, with Resolve-EV controller
6. At this point I should be able to extract the clutch and will get it joined with a coupler I already have at a local machine shop (if I can find one)
7. If possible, I will also commission an adapter plate for motor and transmission at this time.
8. Disassemble battery and plan how to fit it into the CRX. Also begin fabrication of battery box and install it.
9. Wait until 6 & 7 is done. Alternatively, fabricate my own axles for temporary use but this isn't intended for long term (join leaf and CRX axles)
10. Assemble motor+transmission and plan motor mounts
11. Fabricate motor mounts
12. Install motor
13. Power test
14. Run wiring
15. Misc?

I assume something will change in this plan as I go. Something like cooling will need to be considered. Maybe after all this I'll consider how to install air conditioning and heat.

Parts acquired so far:
Running 2013 Nissan Leaf - $5000 (Craigslist)
Resolve-EV Controller - $1072 (900 euros + 15 euro shipping) (https://www.resolve-ev.com/shop/p/resolve-controller)
Coupler - $234 (280 CAD w/shipping) (https://bratindustries.net/)

Parts I need:
Adapter Plate (Nissan Leaf Motor to D15Z1 Transmission)

I'm just waiting for some electrical work to be completed in my garage before I start the project (getting a 240 outlet installed)

Pictures or it didn't happen right?
Vehicle Car Automotive tail & brake light Hood Automotive lighting


Product Circuit component Textile Font Material property


Wood Material property Font Office supplies Electric blue


Resolve EV wiring instructions and owners manual are on their website under additional info:

I've been visualizing the battery removal and watching youtube examples for the last 2 months so I'm itching to get started as soon as I can.
 

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Long gears DON'T work well with an electric motor.

Your horsepower at highway speeds will tank pretty much proportional to the RPM drop.

The Leaf motor should be turning 6 or 7 grand at highway speed...

Any way to shorten the ratios while you have the guts out?
 

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1986 Honda CRX (EM57 2013 Leaf Motor)
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Discussion Starter · #13 ·
Long gears DON'T work well with an electric motor.

Your horsepower at highwat speeds will tank pretty much proportional to the RPM drop.

Any way to shorten the ratios while you have the guts out?
I decided to look up the gear ratios since feel vs numbers differ.

Year/ Make​
Market​
Type​
Tranny code​
1st Gear​
2nd Gear​
3rd Gear​
4th Gear​
5th Gear​
Reverse​
Final Drive​
92-95 Civic CX/VX​
USDM​
Hydro​
S20​
3.250​
1.761​
1.066​
0.853​
0.702​
3.153​
3.250​
And then the Leaf
8.30:1 for 2013-2017 AZE0 (Black interior)
So higher numbers mean more torque, and lower numbers mean less torque right? Am I just understanding this right? I haven't thought about gear ratios too much so I'm open to being educated on this topic.

Going to do more research to try and understand what these numbers mean haha.
 

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You also need to know the ratio of the differential gearing. Not sure what the Ricers have on offer there, but multiplying the trans ratio by the diff ratio to get around 9:1 to 10:1 usually works well. All depends on what top speed you're after in trade for shredding tires at launch.

Others here are more versed on Leaf, so I'll defer to them on where the sweet spot is. It'll also depend on your max pack voltage and current as far as what ratios might work best for your needs/wants.

I suppose you can always drive the highway in second gear 😂

Just do the math to see where it all falls while you have it unbuttoned is what I'm saying. Unless you want to get away from somebody and always be in the garage tweaking on it then close your eyes and go for it.
 

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1986 Honda CRX (EM57 2013 Leaf Motor)
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Discussion Starter · #15 ·
You also need to know the ratio of the differential gearing. Not sure what the Ricers have on offer there, but multiplying the trans ratio by the diff ratio to get around 9:1 to 10:1 usually works well. All depends on what top speed you're after in trade for shredding tires at launch.

Others here are more versed on Leaf, so I'll defer to them on where the sweet spot is. It'll also depend on your max pack voltage and current as far as what ratios might work best for your needs/wants.

I suppose you can always drive the highway in second gear 😂

Just do the math to see where it all falls while you have it unbuttoned is what I'm saying. Unless you want to get away from somebody and always be in the garage tweaking on it then close your eyes and go for it.
You're getting me to question if I want to use the Leaf transmission or the Civic Transmission.

So Final Drive supposedly also means differential ratio accordingly to googlefu. Please advise if I'm wrong here.

So supposedly I'm suppose to multiply gear rotation with final drive to get 1 wheel rotation, so that would be:

Year/ MakeMarketTypeTranny code1st Gear2nd Gear3rd Gear4th Gear5th GearReverseFinal Drive
92-95 Civic CX/VXUSDMHydroS203.2501.7611.0660.8530.7023.1533.250
10.56255.723253.46452.7822.281510.24725

So the motor would turn 10 times before the wheel turns once on first gear.

D15Z1 is 90 HP, 98 lb·ft Torque

Leaf is
Engine power107 hp (80 kW)
Engine torque187 lb-ft (254 Nm)

I guess that really means 2nd/3rd gear would be the most I can go while 1st would pretty much peel out?

I wonder what the risks are for this... I never really thought about what driving 60-80MPH at 2nd gear would result in...
 

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1996 Toyota Land Cruiser
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I would recommend using the LEAF gearbox unless you want a higher top speed. The leaf will go 94mph before it hits the governor which should be fast enough for most people.
 

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The lower Honda ratios are fine... but as you've realized the top two or three are useless.

The big motor speed change when shifting between lower gears is not a problem, because the useful speed range of the motor is so wide; that's why one gear ratio is enough for the Leaf (and most EVs).

The published maps of efficiency versus motor speed and load can be used to choose the best of the available ratios for the power requirement of the moment. There isn't one best motor speed - there's a best speed for each load or power level. With the stock Leaf controller, the same power is available over a wide speed range, so shifting doesn't improve performance unless the road speed is low enough that the motor speed down in the current-limited range, or so high (over about 10,500 RPM in the stock setup if I recall correctly) that the system is limited by battery voltage.
 

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1986 Honda CRX (EM57 2013 Leaf Motor)
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Discussion Starter · #18 ·
I would recommend using the LEAF gearbox unless you want a higher top speed. The leaf will go 94mph before it hits the governor which should be fast enough for most people.
I guess I already have the coupler so I'm going down the civic gearbox route. Leaf gearbox is the backup plan but I'm mainly trying to understand better the downside to using the civic gearbox. It seem as if I'd get more options if I get more gears with the civic.
 

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I guess I already have the coupler so I'm going down the civic gearbox route. Leaf gearbox is the backup plan but I'm mainly trying to understand better the downside to using the civic gearbox.
The Civic transmission is just heavier and more complex than required, and requires the use of both a housing adapter and a shaft coupler. But

It seem as if I'd get more options if I get more gears with the civic.
Yes, even if you rarely shift it, the multi-ratio transmission gives you options. Many years ago I competed in autoslalom events; if I were running those I might use just first gear to run the course, just second gear for most driving on the street, and third gear if the speed and load worked out for that to be the most efficient on the highway... without shifting at all in a typical trip. You could even get a different final drive ratio for the Civic transmission if you wanted to fine-tune the gearing, which isn't likely an option for the Leaf transaxle.
 
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