Datsun Roadster Forum-311s.org

Hello, thought it would be a good idea to start sharing my Nissan Leaf powertrain swap. As far as I know this hasn’t been done on one of these cars before, but if it has, please share! I know other electric conversions have been done, but those have been old low voltage technology. The reason I want to swap to electric, is that it is the modern conversion – the SR and KA swaps are with engines that are over 30 years old now (only a few years young than me!). My goal is to keep the rest of the car pretty stock except for paint color and wheels/tires. Basically, I want the old classic car that looks the part that also just happens to be electrically powered. I have loved my car for 10 years, so I have an idea of what the soul of this car is like – and not try to stray too far from it! My U20 is in need of a major overhaul, so I thought this is the perfect opportunity to try something new.
The intention of posting all of this for feedback from the incredibly expertise that’s exists here. Please question and criticize anything about this conversion, it will probably prove to be quite helpful. My day job is developing and testing heating, ventilation, and air conditioning systems for passenger vehicles, so my process maybe a bit different than some on here. My background forces me to figure out how to create something, figure how it goes together, and functions before many parts are available -so basically, I will be doing a lot of research, engineering, and design before I get hands on with parts. Now experience tells me no matter how perfect I think something will be, at best it’ll be like 90% right, but the more planning that goes into it, the better product it’ll be in the end.
Basic Goals: Exceed power of U20 engine (why swap something if its going to be slower?). Have at least 100 miles of range – in 10 years I have rarely if ever go further than this in one day. Most importantly, keep the car as close to stock as possible – avoid any cutting of body or frame.

Here are my initial thoughts with how this build should go (and please comment away – it can only make the finished product better):
1. “Engine” – The Nissan Leaf Powertrain is the easy choice for me. It keeps it in the Nissan family and actually looks somewhat like a traditional internal combustion engine. Cost is also pretty good due to many cars on the road. I considered briefly of putting a Toyota/Lexus motor/transmission out of the GS450H or similar, but the control would be a little more difficult. I didn’t consider Tesla at all due to its packaging size, difficulty to control, and sheer hatred. The Leaf powertrain stack consists of a motor “EM57”, an inverter (converts DC to AC power and regulates the rotation speed of the motor), and charger (receives power from plug and transfer it to the batteries). The inverter types offered with the Leaf are 80 kW (110 hp, 210 ft⋅lb), 110 kW (148 hp, 240 lb⋅ft), and 160kW (215 hp, 240 lb⋅ft). Inverters are interchangeable with the motor and charge and with some modification 300hp has been achieved.

2. Transmission and Rear Differential – I want to keep it stock Datsun. The Leaf is front wheel drive and comes with an 8:1 reduction transmission – which will be removed as the Roadster is rear wheel drive. My current plan is to couple the electric motor with the Datsun 5 speed transmission. The clutch must be removed and a coupler will connect the shaft of the motor to that of the transmission. The transmission ratios paired with a rear differential ratio get pretty close to 8:1 in second gear. I have some concern if I were to use the 210hp inverter setup with this – would it be too much for the transmission and rear differential? I am going to assume the 148hp would be OK, although 240 lb⋅ft torque might be at the limit of the shafts/gears. This is a pretty typical way to integrate an electric motor into a traditional vehicle. There’s a kit that will be available soon for this for other Datsun/Nissan vehicles. A swap of the bellhousing to the later 71B type would make this potentially a bolt on.
https://bratindustries.net/product/niss ... d-gearbox/
https://bratindustries.net/how-to-mate- ... r-coupler/

3. ECU/Controller – Of course this isn’t part of our cars, but its obviously needed. Resolve EV (https://www.resolve-ev.com/) sells a kit that will be suitable as long as all the Nissan Leaf Parts remain intact in the system. My plan is to buy a wrecked Nissan Leaf so I will have access to all the necessary parts.

4. Batteries – Due to the constraint of the Resolve EV controller, Nissan Leaf Batteries are the only option. They aren’t the best in the business, but they don’t require any type of active heating and cooling which makes things much easier. The challenge will be to package 24 cereal box sized batteries in our small cars without destroying any of the feeling and handling of the car. Eight batteries fit where the gas tank is. Another 12 fit very nicely in the truck (see cardboard mockup picture). That leaves 4 more to put maybe up front under the hood or in the trunk. The weight distribution will probably end up close to 50-50 which wouldn’t be too bad I think.

5. Heating/Cooling – The powertrain stack is cooled by a traditional type coolant loop with a radiator and fan. The stock Datsun one is certainly large enough (I already run a champion radiator with an electric fan). Heating the cabin no longer benefits from free engine waste heat, so something new will have to be installed. The easiest option would be to use a PTC heater from the Leaf and put it in the HVAC Unit if it fits (probably doesn’t). Next easiest thing would be to use an electric coolant heater and plumb it to the existing heater core and use a water pump to circulate it. As an Automotive HVAC engineer, my personal preference would be to be fancy and carry over the AC and heat pump system from the Leaf and keep the existing Datsun HVAC unit and everything cabin side of the firewall stock. As the main radiator is now a low temp radiator, water could be diverted from there to a water cooled AC condenser. Couple the water cooled AC condenser loop with a normal AC system but then do another refrigerant to water condenser loop to put cold water back into the cabin heat exchanger. Run it all in reverse and you get heating instead of cooling. Lots of effort but besides me probably only like 6 people on earth will find this interesting, haha. I’ll have to test this on a bench setup first, but at least the car would have AC and heat though utilizing the existing HVAC unit with little modification.

6. Electrical – I know the gas pedal will have to be replaced with an electronic one. A push button to start the car will have to go somewhere. The Resolve EV controller comes with a little digital screen which can be hidden somewhere. The 12V electrical system will remain intact and the stock wire harness can be used. Since the transmission has the speed, that speedo should still work.

Probably forgetting more details, but that’s what more research is for. I’ll fill in more precise info once I get around to it. My car is currently tore down completely. I painted the frame and will bolt the rest of those components back on soon. The body is at a shop of one of the guys I work with who does show winning quality work but its super slow but very reasonable cost wise. Once I get the frame done it will be reunited with the body and painted. I know this is in the reverse order for an engine swap (do the engine first and then finish the body) But unfortunately, my job will delay the project a bit as I will be sent to our Datsun’s homeland for a while to learn some pertinent things. Should give it plenty of time to be painted nicely! Until I get back to the US, I will continue my research. Please contribute as I can see a swap like this being the future for our cars as times are changing (very quickly, thanks California). However, in the end my goal is to keep the Datsun as close to what it originally came out of the factory as, but it’ll just happen to be electric.

Some interesting related builds to reference:
Toyota Land Cruiser: https://www.diyelectriccar.com/threads/ ... ev.204875/
Toyota GT 86: https://openinverter.org/forum/viewtopic.php?t=326
BMW 2002: https://www.diyelectriccar.com/threads/ ... 2e.203918/

Ambitious project - This is a thread I’m going to be following …

Awesome project, good for you, and Roadster owners. I'll be following and am in complete support of your project!

Insurable this way ?
Your troops highway patrol station vehicle inspector will know & if they allow it

I'm In! I know the Datsun's days are coming to a close...

Thank you for all the support! Redroadster - I contacted Hagerty (my current insurer) and they said they will insure an EV conversion. They prefer it be done by a professional shop or a off the shelf kit by a "reputable" shop(which actually the controller and transmission adapter plates are so that may be acceptable) but if not you have to jump through a few hoops to prove the car is safe, but its generally very do able. I have read in other forums people occasionally have had trouble insuring, but eventually it gets resolved. There's more and more conversions being done so its not like this is something strange or something they haven't seen before.

I called Hagerty to get the insurance , it sounded good .2 yrs ago
The guy asked If I wanted the -at event coverage- too, I said I just want regulat car insurance , he says
Sir , this is classic car insurance which means it has those plates
Classic car plates only allow the thing to drive to and from a show / display or parade , up to 190 miles , otherwise
You can't even drive it to get gas / around the block and look at the contract on regular car insurance the 11to14 p one, it lists acceptable mods which are quite minor . Ohio is the same rules, I checked here the plate is taken off the car if the driver wiffs on what event he's going to. Your supposed to have the event windshield sticker on to & from .All the other insurance companies are funded by multi billion $ investment firms Hartford they don't have that behind them
You can be facing a felony for fraud... kinda like going down in the stadium to sit in good seats that no one showed up for , & the usher catches you they're sold by the yr for $$$$
Hagerty says it can't be a daily driverv & then states just keep driving close to home ....which seems like they're trying to make it work that way, but get in a bad wreck , they have a quick out

Thank you for your concern. In Ohio, it seems Hagerty may have different policies than what you think you have in your state - even for conventional cars. If it doesn't work out with them there are other insurer options - as there are thousands of EV conversions nowadays there certainly is a legal path to insure them correctly. Hagerty's website even offers insurance for modified cars: https://www.hagerty.com/insurance/class ... d-vehicles

Fully subscribed! And I have questions, so bear with me as I am fascinated with the technology...

2. Transmission and Rear Differential:
I clicked the adapter kit links you provided and I'm still confused...The Leaf electric drive unit will be mated to a clutchless Datsun transmission--I think I understand that part, but then you retain a functioning 5-speed shifting experience/operation? I thought all EVs just had a "Drive" selection with zero user-input on gear selection. How would it operate without a clutch? Does the roadster become a two-pedal car?

Rear-end...curious how the stock rear end would cope with instant torque!

4. Batteries
Have you considered putting a motor over the rear wheels? Batteries could be placed above in trunk/parcel shelf and of course the empty engine bay (or potential "frunk"?)
How do you envision charging? Will it be just like charging a Leaf?

Brakes
From my experience with a Tesla and instant torque/power there is no way the stock brakes could survive without overheating. What are your plans for braking/hydraulics and will you be able to include Regenerative braking?

mpowers wrote: Wed Aug 31, 2022 4:01 pm I didn’t consider Tesla at all due to its packaging size, difficulty to control, and sheer hatred.

What's to hate? I am still impressed by the Tesla performance. My folks have a Model Y and I've commuted in it a few times. I can't believe they give this kind of power to civilians. A Tesla-powered Datsun Roadster would be batsh!t crazy.

On a non-technical note...the whole EV experience for me was just plain eerie in the beginning...the silence accompanied by just wind and road noise. I've seen EV-converted E-type Jags, Cobra's, 914s, etc...sports cars that I just can't imagine merging on the freeway with literally no iconic exhaust sound. I'm that guy that rolls his window down at stoplight to hear someone else's engine. Maybe it ends up like the Tesla experience...you hop in your Datsun and traffic disappears as you squeeze the pedal...without engine sounds.

Did you imagine life with a silent Datsun Roadster or was that a total non-issue?

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. The range of the electric motor is 0 to around 10000rpm, so in the stock Leaf setup, there is no shifting at all. However, as many conversions retain the manual transmission, from what I read most people use a few of them still. For instance, put the car in 2nd gear around town and then shift it to 4th or 5th if you are going on the highway. The acceleration rate will change as the gear ratio will be different. Some conversions keep the clutch, but since there range of the motor rpm is so much greater, there really is no need to shift. Obviously losing the fun of the 3rd pedal is a big deal, I don't like this, but there are other aspects of the conversion I look forward too.

You are right, I am also concerned about the rear end and if it can take the torque, if anyone has experience with what the max torque they have put to their stock rear end without breaking it, I would appreciate it!

Yes I considered putting the motor as the rear differential, but that amount of fabrication is out of the scope of my abilities as it would take major modifications- unless someone has some creative ideas they can share. I also like the idea of keeping the car as close to the same design as it is now; front engine, rear wheel drive. The more I change it, the less Datsun it'll become. But of course if the motor is in the back I could keep the Leaf transaxle which eliminates parts and other potential failures...so that would would be good.

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 honestly don't like it as its always been weird to me in the cars I've driven, but maybe I just wasn't used to it. Regardless this is an area I need to do more search in.

You are absolutely right that the performance of a Tesla is amazing, if not actually nauseating! Plaid mode is certainly something special for sure (two runs of 0 to like 80 was enough for me), but in the future it really won't be. Electric car horsepower is dependent on the the current and voltage available from the battery (P=IV). The bigger the battery, the more power it can provide. Because Tesla's battery technology is quite good and they don't prioritize durability, they allow the battery to max out the power on demand. For many EVs coming out now and in the future, 400-500 hp will be commonplace. Of course there will always be performance models, so 1000 hp really won't be out of the reach of many people as it will be cheap and easy. I hate Tesla for more other reasons; besides the powertrain, the rest of the cars are incredibly cheap (understandable as they have to pay for an expensive powertrain and batteries). They are the current "Cool Kid" on the street so other company will try emulate aspects of them. For instance, take the big screen on the dash. You must use the screen for nearly everything which is actually annoying. People see that as really cool and futuristic but its just to save cost. Now lots of other cars have this big annoying screen that in 5 years will be obsolete and function as poorly like an old cell phone. Also advertising your car as having "Autonomous and Full Self Driving Features" is outrageous. Sure they do well on the high and maybe in the city but there are still limitations to the systems capabilities. How many times of you driven by a Tesla driver and they are reading a book or looking at their phone? Generally Tesla owners seem to be a bad combo of BMW and Prius drivers on the road. I hate the panoramic roof trend, the bland aerodynamic styling of some EVs like there's, I could go on...I just don't see the appeal outside of the acceleration capability.

In regards to engine noise, I will miss it - the Datsun will have terrible wind noise without an engine. I was driving a Ford Mach E recently and it has way to create propulsion sounds in the cabin. I actually liked it a bit, I would consider doing the same for the Datsun as fake as I know it is. Most luxury cars with internal combustion engines do this nowaday anyway so its not that unusual. I guess its not really any different than tuning an engine or exhaust for better exhaust note.

For insurance and registration purposes, the age of a classic car, in most cases, is at least 20 years old but not more than 40 years old. If you are going to register it (and insure it) as a classic, it should have been kept to its original design and specifications.
This copied off the collector car info search .
Hagerty insurance listed with many other collector car insurers .
YOU DO KNOW the battery safety, wreck wise is a big concern in EVs as it can become a huge arc welder type arc / fire 11,000 degrees .. in milisec.

Marc, I don't know the first thing about an EV swap, but your description and detail as to how and why(!) is awesome.

I will be following closely, and wishing you the best of luck.

Neat stuff.
Peter

So I am starting to put parts back on my redone frame and was wondering if I should keep the rear sway bar. I know it’s controversial, but the battery will add quite a bit of weight in the rear. Thoughts?

Sorry, no clue for the sway bars .... but ... I will be keenly following this build. Mark, it sounds like you are putting a lot of thought into this, and you're going to the engine swaps of the future, now. I know just enough about electricity & car mechanics to be dangerous ... so here's a couple questions...
re torque....with all the electronics and controllers, can torque be controlled & limited electronically? (kind of like rpms can be limited in an ICE). Maybe match the max torque on current engine swaps with stock rear ends to be safe?
re brakes ... how much heavier will the car be?... I have stock brakes & hate them in the wet on the highway. New brakes is pretty high on my upgrade list ... even with the U20
re battery placement... is there room to put some at the frame level like the (dreaded) Tesla? If each module is the size of a cereal box, unless they need to be in a special safety cage, could a few fit against the frame? might be able to pack more in...and the car would handle even more like a go-cart.
Last one ... per Jeremy Clarkson & The Grinch..."The noise ... THE NOISE". How I'd miss the carbs & exhaust telling me what the engine is doing. So if we can emulate that digitally, the boxes would mostly be checked.

Good luck with the build...I, too, will be watching closely!!!

The noises can be made -