Project Fig-Leaf

[james@N52E01]

Welcome to Project Fig-Leaf. I am converting a Nissan Figaro to electric using a Gen 1 Nissan Leaf as a donor. The aim is to use as many OEM Nissan parts to complete the build and to make the conversion fully reversible.

Here’s where we are so far:

FIGARO
At the end of 2019 we completely stripped out the Figaro to have the bodywork restored. We soon found out she was beyond repair.

Thankfully we have a second working Figaro which will be converted instead (now with plenty of spares). Meanwhile, the original crumbling frame will be used as a testbed for the new drivetrain.

LEAF
The Leaf is a 2013 registered Gen 1 leaf with 52k miles. Leaf spy rated the battery at 75% SOH. All of the main power electronics have been removed (motor, inverter, pdm, battery).

We will attempt to run the motor through the leaf gearbox and use the original driveshafts from both vehicles to make temporary shafts, similar to Shane from Performance EV’s Porsche 911. We will then have custom drive shafts fabricated.

The next step is to use Damien Maguire’s VCU bought from evbmw.com to control the inverter through CAN messages.

This will be a community build, so I'd like to end this introduction with a huge thank you to all the community for your support and to Damien and Kevin for their excellent EV conversion course.

More soon...

[Kevin Sharpe]

Thanks for posting James, I'm watching this project with interest

[james@N52E01]

Time for a well overdue update. In my first post we removed all the power electronics from the leaf. The motor and inverter are now ready on a test bed and I have just picked up a Gen 1 Prius battery to test with. Hopefully we should have the motor spinning in the coming weeks.

I also managed to get my hands on the entire front section of a figaro which was bound for the scrap heap. The plan is to suspend the front section on a jig to make fine tuning the motor position and drive shafts much easier.

Next, I adapted the Leaf’s original wiring harness to work with Damien Maguire’s VCU.

The board will take inputs from the Leaf’s original throttle and send CAN messages to control the inverter.

I still have to figure out how to release the parking actuator located in the gearbox. Once that’s done I should hopefully have some footage to show everyone. Stay tuned and thanks for reading.

Edit: I just released the parking actuator manually. Remove the 3 12mm bolts holding the actuator motor in place and lift it off to expose the splined shaft. A gentle turn of the shaft anti-clockwise by about 10° with a 12mm socket will release the actuator without damaging the shaft.

[jamesN52]

Testing the ISA shunt through the Leaf VCU board with a 12v 5a headlight bulb

[Kevin Sharpe]

Testing the ISA shunt through the Leaf VCU board with a 12v 5a headlight bulb

That's good news

[SciroccoEV]

We will attempt to run the motor through the leaf gearbox and use the original driveshafts from both vehicles to make temporary shafts, similar to Shane from Performance EV’s Porsche 911. We will then have custom drive shafts fabricated.

There is no need to spend good money on custom driveshafts. I've used cut and shut driveshafts on projects up to 300+ horsepower and many FWD cars used welded driveshafts (at least on one side) as standard.

I used to get mine done by RecoProp in Luton, but they're long gone.

Every shaft failure I ever saw had been sleeved with free machining mild steel, which contains either Lead, Sulphur, or both. You can't get sound welds in steel containing those elements.

[james@N52E01]

We will attempt to run the motor through the leaf gearbox and use the original driveshafts from both vehicles to make temporary shafts, similar to Shane from Performance EV’s Porsche 911. We will then have custom drive shafts fabricated.

There is no need to spend good money on custom driveshafts. I've used cut and shut driveshafts on projects up to 300+ horsepower and many FWD cars used welded driveshafts (at least on one side) as standard.

I used to get mine done by RecoProp in Luton, but they're long gone.

Every shaft failure I ever saw had been sleeved with free machining mild steel, which contains either Lead, Sulphur, or both. You can't get sound welds in steel containing those elements.

Thanks SciroccoEV, it’s good to get the benefit of some hands on experience. I have recently thought about milling new ends on the existing Leaf driveshafts to fit into the outer CV joints of the figaro as they are about the right length and a similar spline pattern (but about 2mm greater diameter).

If I went with welding the two shafts together, is there a sensible place to make the cut (I.e. nearer inner CV joint/middle of shaft/near to outer CV joint). Not sure what effect either would have on the torsional strength of the part.

[SciroccoEV]

When changing the length of shafts, I've always made the join it in the middle. When making a hybrid shaft, I'd use the maximum length of the most slender shaft.

The sleeve should be a press fit on the shafts and you need to watch out for distortion during welding. Ideally a motorised weld positioner is used, although many shaft shops use an old lathe.

[MattsAwesomeStuff]

When changing the length of shafts, I've always made the join it in the middle. When making a hybrid shaft, I'd use the maximum length of the most slender shaft.

I'm not sure what this means. Wouldn't you want the maximum length of the fattest shaft, because it's stronger?

Do you make the cut square or diagonally? How long do you make the sleeve?

One of the biggest limitations I run into from people who would like to adapt a whole rear end (like the Toyota MGR for example), but the driveshaft width is too long. You're saying that that could be DIY'd by an average builder?

[SciroccoEV]

I'm not sure what this means. Wouldn't you want the maximum length of the fattest shaft, because it's stronger?

Since the smaller diameter shaft IS the weaker, you want to spread the stress along as much length as possible.

Do you make the cut square or diagonally? How long do you make the sleeve?

Cut then machined square and parallel. The sleeve should engage with each shaft for a distance at least equal to its diameter.

One of the biggest limitations I run into from people who would like to adapt a whole rear end (like the Toyota MGR for example), but the driveshaft width is too long. You're saying that that could be DIY'd by an average builder?

The average builder with a well equipped machine and fabrication shop, maybe...

However there are always other ways to get things done. Many areas of the country will have a local model engineering society who may be able to ask around their members to see if someone can help. There are always back street machine shops, etc.

[james@N52E01]

When changing the length of shafts, I've always made the join it in the middle. When making a hybrid shaft, I'd use the maximum length of the most slender shaft.

The sleeve should be a press fit on the shafts and you need to watch out for distortion during welding. Ideally a motorised weld positioner is used, although many shaft shops use an old lathe.

Is this the kind of motorised weld positioner you mean?



Interesting point about Spreading the load across the most slender shaft.

[SciroccoEV]

Well, as the video title indicates, that's a friction welder, a rather more specialised and expensive piece of eqipment.

A welding positioner allows controlled rotation of an item so that you can keep the welding torch and therefore your hands in one place, rather than trying to move around the part. It enables making a more consistent weld and also doing so in one pass, rather than in sections.

If you can rig up a way to support the shaft and allow smooth rotation, then an assistant can do duty as a weld positioner.

[arber333]

I'm not sure what this means. Wouldn't you want the maximum length of the fattest shaft, because it's stronger?
Do you make the cut square or diagonally? How long do you make the sleeve?

NO NO NO!
You have to make joining both shafts so they both share torque as it would be a single homogenous material.
This cannot be achieved by welding the circumference only. Welding heat causes changes in material that make it brittle and it can also introduce micro cracks... Also sole weld along circumference WILL fail since torsion in one shaft is trying to tear off from the second one.

Ideally best way would be to make a inner splined collar with both shaft ends having splines.

However we do not leave in the ideal world. Here is the next best thing...
So i got my shafts from Leaf and the ones from 406C to my friend who had a lathe.
We measured (a lot) them and finally we ground down Leaf shafts a bit; because they were thinner. Then we turned Pug shafts from the inside because they were hollow and much larger than Leafs.
We shaved just enough material from both so that i could get like 60mm of leaf shaft inside Pug shaft. If you can use more length... by all means, do it.
Then i drilled one 8mm hole 25mm along the outside shaft (Peugeot) and another one at 90deg to the first one and 25mm doiwn the length. This drilling was a bi...ch! Driveshaft steel material is hard.
Then i assembled shafts to previous length of the Pug shafts and tack welded them together.
Yes, then i closed weld along circumference. But not only.
Next i welded the holes and waited with the liquid metal pool a bit more time so both shafts were joined together to a 90deg phase difference.
This weld offset makes both shaft ends act as one single material under torsion load, which is desired trait in shafts.

Finally you have to anneal the stress in shafts. To do this we used acetilen welding rig my friend has. He heated the whole assembly to yellow collour and we let it to slowly cool down. This procedure reduces stress in welded material and whole weld becomes more tough.
Dont ask me about annealing temperature for my shafts. I know the theory behind it and i know what colour tables to use, but really i let my friend make this because he had done it many times. You absolutely need this step! So if not sure go find someone who knows how to do this.
https://leafdriveblog.wordpress.com/201 ... extension/

[james@N52E01]

Things are finally progressing with the car, after struggling to finish the first motor mount I was contacted by a friend who also attended the EV Conversion Course last year in Ireland (new course dates will be posted in the events section soon). Pedro at I N Autos in Lingfield, UK and his team offered to help with the design and fabrication so I transported the test rig and our donor Figaro down to them in Surrey.

After much measuring with the car on various mounts to test the full deflection range of the original shafts, it wasn't long before the motor mounts started taking shape.

As you can see they have done a super job of making use of the original engine mounts. The Figaro Shop also make a set of polyurethane bushings we'll be using later on. The driveshafts should be finished next week, so hopefully we'll have some interesting footage soon.

[arber333]

Also there is the thing i forgot to mention before. When splicing shafts you need to observe some rules that i did not...DOH!
For example i forgot to take into account that when wheels sit on ground shafts are almost level and your hypotenuse turns into catete which is considerably shorter. Of course that means to pull tripod halfh way out of its place when cutting shaft to length! When i forgot this part everything was fine except when driving shaft was rubbing the lip of bearing case. I needed to reweld it 20mm shorter which is considerable.
viewtopic.php?f=11&t=73&start=60#p16501

Just a reminder.

[james@N52E01]

Thanks arber333, we're taking measurements of the shafts at max downward extension (suspended from jacking points), average deflection (unladen weight on wheel ramps) and max upward deflection (max gross weight). Would be interesting to know the wheel to CV length so we can compare? Thanks also to you, MattsAwesomeStuff and SciroccoEV as well for your experience with fabricating drive shafts. We're going to try a couple of different methods, initial shafts will be welded up based on your recommendations. The final shafts will probably be turned from hardened steel to make the DVLA happy

[james@N52E01]

[Cookie6000]

Brilliant! Well done James. Great work the last couple of weeks. Have you found a way to dial in the regen on the Leaf VCU?

[james@N52E01]

I’ve found the inverter will accept reverse torque commands with the CAN still broadcasting the Drive gear message. The plan is to write a simple negative torque command that is associated with the brake light switch which will cut out at approx 100rpm (to prevent the car trying to go backwards at a dead stop.

I also plan to write in a selectable drive mode which extends the throttle sweep range from say -100 to 2000 trq value with the same 100rpm cutout. That will hopefully make the accelerator pedal act like the e-pedal on the 2018 Leaf (all these values will be tested and tweaked).

Should have the system installed in the car next in a week or so and start trialling the code to make sure it works then will post it on here

[james@N52E01]

[SRFirefox]

I caught a glimpse of that EV grin before you went past the camera! Congratulations on getting this far! This is a great little car to leaf-ify. More power than you will ever use in that tiny chassis!

[mdrobnak]

Indeed, good work!

[RetroZero]

Very good job, and congratulations on that monumentous step!!

[james@N52E01]

Thanks guys Really pleased with our progress and a massive thank you to Pedro and his team at I N Autos and their amazing fabrication work. Having the whole setup working on a test stand meant we were able to remove the engine, install the new motor and have the car running electric for the first time all in one afternoon.

[james@N52E01]

Maiden Voyage:

This is our first driving test running with Max Torque set at 200 (10% of what is being implemented in v1.5 of the VCU code)