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Working on a 1989 Classic Mini EV Conversion

12550 Views 80 Replies 10 Participants Last post by  scottherrington
Hello Everyone,

Starting work on my 1989 Mini. Thinking of keeping the original gearbox and mounting a Hyper9 motor directly on top of it. Using SilentSync sprockets and belt as a drive system. Have something similar to ´s conversion in mind. But interested in using the Hyper9 9 and some Tesla modules from the get go.

Also considering the EV Europe system:

I have no advance knowledge in EV conversions so I want to keep everything as simple as possible for this one.

Interested in getting some feedback from you guys who are the experts. Let me know your thoughts.

Am I in the right path or is this combo I have in mind a not so good Idea.

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What is SilentSync? Driving a Mini transmission with anything other than a Mini motor is...non-trivial. They're also designed to handle less than 100ftlb of torque...An option there would be to use a Honda conversion subframe and transmission (which opens the door for AWD), but it's still tricky to get a belt/gear system working to spin it.

Tesla S modules have good power density, but their length makes them tough to fit. Were you planning on keeping the rear seat? What range are you hoping for?
Nice little lump, but unless they'll also sell you a Mini subframe that fits it, I'm not sure I see the point over a Leaf (unless they're hard to find?)...

£6,400 is pricey...Even £2,000 is...
See if you can get a subframe and axles, too...They build these things (but charge six digits):
I have converted my Mini with a 27kW-powertrain (from a Th!nk as donor car). With these 27kW I can make the front wheels spin at any time I want (sometime I fail to avoid it) from zero to approx. 60km/h.
Nice! Do you have a page or thread with more details? How do you control the motor? Did you keep the Mini gearbox?
Nice! I wish those cars were sold in the States.

Maybe if I get real crazy, I can try and put a Think motor in the front, and put my Leaf motor in the rear with this cage:
If you want higher voltage, the cost is money, weight, and space. There's no great way to get high voltage with less weight...Prius and Tesla/Smart battery packs have high voltage per pound/liter, but the former lacks range and the latter costs a lot. Well, arguably. You can buy a Smart Fortwo ED in good condition for about $5k, netting you about 18kW and 350V in a ~300-pound pack.

If I were you I'd try and put half the modules up the middle above the exhaust tunnel, and half under the rear seat (this is what Swindon does)...and just...add more...

My car just has 30 Leaf modules sitting on the rear seat. Weight distribution is looking like it will be between 50/50 and 55/45 front/rear, and total weight is maybe 200-300 pounds up from stock. Considering this car was (somewhat) designed to have rear passengers, I think you'd be good if you're willing to lose those seats. Might still be good by putting aTesla module or two between the front seats and one or two in the boot.
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Random thought: There's like an open block under the boot (twixt the rear subframe) that isn't the lowest part of the car, and is only blocked by the recessed battery box in the trunk. Might be a spot to get a pair of modules if they fit and if you're willing to build a box to protect them. Nice and low, and half in front of the rear axles.
I've been exploring this myself:

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How many kWh is that?

Space in the engine bay is tight, but if you ditch the brake booster a lot of space frees up. It seemed like a real pain to get a useful amount of Leaf batteries up there, but it seems like maybe the OXT batteries will fit. I wonder if you could get two...

What's the motivation to keep the rear seat? I put a 200lb guy in the back of mine once, and the car was almost dragging on the bump stops...

Trunk space is ample.
My car's acceleration is for sure limited by traction up front,'s still quite the little monster. Not having experienced the insanity of a Honda B conversion, maybe it's tame, but...moving to rear or AWD would take quite a bit of work, and even then you'll introduce the fun of accidental throttle-induced oversteer. Crazier Minis have been built, but they often come with the disclaimer that maybe they went too far beyond the fun zone. I choose to be content with some throttle modulation until 30mph or so.

I'm of the mind that I worried about weight distribution too much for scooting around the city (which is the purpose I built it for). It sure does well on Mulholland Drive, which is nice. That said, I'm not sliding around on public roads, so I can't tell you how it feels at the limit.
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