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Discussion Starter #1 (Edited)
Hi All

Ive been lurking for a while and I thought its time to finally start talking about my first EV conversion project.
Ive owned minis since i was a kid and had so many over the years ive lost count.

I have been looking at EV conversions for sometime and speaking to Chris at Zero-Ev and seeing some of the awesome work from people on here i thought i need to look into converting a mini.

The mini you see for my project is a 1971 Mini Marcos Mk4, full GRP monocoque shell using the mini drivetrain and subframes.
I was going to turn this into my trackcar as I dont have anything for trackdays at the moment although i have 2 caterham chassis' sat in the garage (yes one will become electric!)

To this end i have started up a website www.electricclassicminis.com and have an instagram account to showcase all the work people are doing to there classic minis.

At the moment im still trying to figure out what drivetrain I am going to use. There is the popular leaf conversion, using a hyper 9 mounted to a Honda or Vauxhall gearbox,and retaining the mini gearbox and mounting a motor on the top.

As people know the mini is quite a compact car and there isnt much room to package anything, my biggest concern with this project is batteries as I want to be able to use the car at a local track about 20 miles away and do a couple of track sessions whilst there.
Having a large enough battery pack that will deal with extreme usage isn't going to be easy, but as I'm an engineer i love a challenge.

I will say this now my pet hate with working on cars especially minis is the electrical gremlins, ive never liked electrical work so this really is a baptism of fire.

I will be no doubt asking lots of stupid questions, but any help is greatly appreciated.

Cheers
Gaz

 

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Excellent!
As a long term "Mini Guy" I approve

One of my pals had a "Midas" - similar to the Marcos

If I was doing that I would start by buying a complete crashed Nissan Leaf and work from there

Back in the day I put a Lancia twincam in my old mini

I would also say that converting one of your Caterhams would be a LOT easier !! -

My car is similar to a Caterham
https://www.diyelectriccar.com/forums/showthread.php/duncans-dubious-device-44370p15.html?highlight=duncan

It's using a Chevy Volt battery pack and a forklift motor (Hitachi) where the gearbox would normally live
 

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Discussion Starter #5
Cheers Casper. I've got a pickup in the garage but it's not going to be converted..... yet.
I know a fair few of the norsk mini cooper club and had a few drinks with them again this year at the imm.
I love your pickup too, I think I contacted you before? Maybe through the mini forum?
As I've stated I'm not great at electrics hence why I've stayed in the shadows until now. But hopefully I will make up my mind on the powertrain soon.
 

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Discussion Starter #6
got round to looking at what the motor looks like sat on the gearbox for real, the hyper9 seems a lot bigger when sat ontop of the gearbox!

I still have a lot of design and prototyping to go, I'm contemplating a belt or chain drive rather than using the original drop gear setup the mini utilises.

Any suggestions greatly appreciate
 

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got round to looking at what the motor looks like sat on the gearbox for real, the hyper9 seems a lot bigger when sat ontop of the gearbox!

I still have a lot of design and prototyping to go, I'm contemplating a belt or chain drive rather than using the original drop gear setup the mini utilises.

Any suggestions greatly appreciate
That motor does look huge. :eek:

An alternative, avoiding chains or similar questionable mechanical arrangements, would be to mount the motor to a Honda transaxle, and mount that using one of the subframes sold for Honda engine conversions. This assumes that the motor is not longer than the Honda engine used in these conversions.
 

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Discussion Starter #8
Hi Brian
Ive been looking at other gearbox alternatives including the honda and the vauxhall gearboxes as I know allspeed engineering well as ive done a few 16v conversions on minis over the years.
Im probably going to go for a PG1 gearbox as an alternative as its out of a rover and i want to keep the drivetrain rover/bmc if possible :)
 

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I should have reviewed the earlier posts and realized that you would be pursuing this approach. I only mentioned Honda because that's the conversion that I have most frequently seen; the PG1 looks like a good choice, both for the Rover/BMC connection and for the broad range of aftermarket support for possible later upgrades.

There's even a Quaife sequential-shift dog-ring gearbox available for the PG1 case. I think that this type of fast-shifting box could be a great match with motor, given no clutch and a controller which rev-matches automatically... but that's a refinement project for later.

How does the HyPer9 motor length compare to the length of the Rover K-series engine (which is what I assume people swap into Minis using the PG1 transaxle)?
 

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Discussion Starter #10
So I have picked up a 2014 hybrid rear diff from a mitsubishi outlander. It fits into the subframe but I will need to relieve the rear of it to allow the unit to sit back 15mm to line up with the driveshaft exits.
I have no idea on how to make the electrical side of this work yet, so will be asking for advice from the community on this.

I think this compact unit could be ideal as it has up to 80bhp and in a mini that's more than enough. Although I would still like to do a hyper 9 with pg1 dpgbox for track use in the Marcos.

If anyone has any knowledge about these units please get in touch.
 

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So I have picked up a 2014 hybrid rear diff from a mitsubishi outlander. It fits into the subframe but I will need to relieve the rear of it to allow the unit to sit back 15mm to line up with the driveshaft exits.
That looks promising. :)

I have no idea on how to make the electrical side of this work yet, so will be asking for advice from the community on this.
Do you have the controller/inverter from the Outlander as well? Then it would be the same challenge as others using salvaged complete drive units, of figuring out how to talk to the controller (presumably over CAN) and how to keep it happy without rest of the vehicle's systems talking to it.

If you use a different controller/inverter, the challenge is finding one which is compatible with the motor's encoder, and tuned for the motor's electrical characteristics.

Sorry, I have no specific advice for either scenario...

Do you know if this Outlander PHEV rear drive unit is related to the drive unit of the i-MiEV? They're the same format and at least approximately the same size and power. If they are related - or even the same - someone with i-MiEV experience may be able to help.
 

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Nice! Beware of cutting too much out of the back of the subframe. At least on my car, the body and steering rack are located immediately behind it.

I'm trying to get axles as even in length and angle as I can in an effort to minimize torque steer. I'm not sure how much of a difference it will make, but it couldn't hurt.
 

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Discussion Starter #13
yeah ive done a few conversions over the years with either homebrew or the K series metro subframe so aware of the challenges with packaging in the mini.

I think i should have enough room without clashing with the steering rack.

I see electric classic cars are now trying to fit a small tesla motor in the front of a mini, so keeping an eye on that too.
 

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I see electric classic cars are now trying to fit a small tesla motor in the front of a mini, so keeping an eye on that too.
Surprising. Do you have a link? I think they're gonna have a bad time, 'cause though the motor is a bit more compact than a Leaf, the gearbox protrudes out even further from axle center, which will make the tricky spot trickier.
 

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I see electric classic cars are now trying to fit a small tesla motor in the front of a mini, so keeping an eye on that too.
I think they're gonna have a bad time, 'cause though the motor is a bit more compact than a Leaf, the gearbox protrudes out even further from axle center, which will make the tricky spot trickier.
It's worse than that: unless it's a Tesla-supplied drive unit from something like a Toyota RAV4 EV or Mercedes B200e, or the rear motor of a Model 3, the Tesla motor is behind the axle line. There's no chance of that fitting in the front of the Mini without turning it around (which means a reversed oil pump, at a minimum) or rotating it over (so the oil pump pickup is wrong, at the very least), so the motor is in front of the axle line.
 

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There is a problem with using the mini suspension

With 40 hp it was great
With 75 hp - it was beginning to show it's limits (Cooper S)
with 112 hp - it was not the best - (my 1430)

Mini suspension with 150 hp plus - will simply not be very nice -
 

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Hi pickmeup

I have a complete i-MIEV drivetrain system and it does look simar to your outlander unit. I was about to suggest something like it before reading this so glad you found it.

Regarding controlling it, I've considered different options also and as I understand it, unless you use the OEM logics of the controller (software/programming) it makes little difference what controller you use apart from the encoder compatibility as was mentioned. The likes of Curtis or SEVCON controllers have self-tuning functionality that would get you running enough to tune the parameters further yourself on the road so to speak, or if you like a project, the DIY controllers on the forum are great options.

I'm planning to cheat and use the entire OEM system of my donor and simply reprogram the performance to delimit the KEI car performance of a stock i-MIEV. But I have other drive units that I intend to use a self tuning Curtis controller.

Not sure any of this helps you but I'm enjoying following your build, thanks. And an 80bhp EV Marcos/mini will be delightful to drive. Good luck with it, I'll be following and happy to help if I can.

Cheers
Tyler
 

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Discussion Starter #19
Hi Tyler
Thanks for the info, as Ive said the electrical side of things is a big learning curve for me, hence looking at fitting the motor/box and possibly looking into battery box location(s) and size first as packaging in a mini is bad and even worse in the Marcos.


Ive found a few threads on the i-Miev so trying to look at what i can learn from it.


I may be in touch with you to see what i can learn from you playing with the performance of the stock unit.
 

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Hi Gaz

I'm confident my unit is similar to yours as it's rated the same, though as I mentioned is limited to KEI car specifications as stock. One thing I want to try is download Mitsubishi tuning/remap software that the Evo guys use for DIY tuning the ECU and hope the language is compatible to read and edit my controller parameters.

This could be an option for you to try if you can get an Outlander inverter and it might allow you to learn the CAN language and controls or even remove the OEM restrictions to allow it to run stand alone in your car.

1 consideration also is that the output in the Outlander is dependent on battery conditions and I understand the inverter is heavily dependent on BMS communication to manage power consumption levels therefore restricting power draw. I believe these units can safely run at 80kw of power meaning you could push it a bit harder with a suitable battery.

Mitsubishi built a showcase hill climb car for Pike's peak in the USA using 2 i-MIEV drive units each reportedly running at 80kw for a sustained period (if you know the race it is tough and rather long for a hill climb) so the motors can take a bit of abuse. I doubt either of us aspire to this performance but I've wondered about having a race button that unlimited the power for traffic light drag races or something short term just to annoy boy racers etc. Point being the drive units are strong and reliable and good potential for your conversion.

Hope that helps you a bit.

Cheers
Tyler
 
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