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Working on a 1989 Classic Mini EV Conversion

12556 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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I have converted a 77 moke and successfully kept the original transmission. It works but it was a pain to do and the gearbox is noisy and I'm always worried I'm going to destroy the 40 year old Leyland gearbox /driveshafts with the new power.
If I was to do it again I would look to drop in an imiev running gear or maybe fit a rwd cars diff to the front and belt/chain drive it with the motor sitting on top of the diff.

do you have any links to the build and how you adapted the box to work? Are you using the original transfer gears or a chain/belt drive to the input shaft?
the guys at swindon powertrain are very clever guys, i do think 6400+ VAT is a bit pricey considering you will need to buy all the other relevant items to make it work.
Its a nice compact unit making it ideal for a mini which i have seen in the flesh at the CENEX show in the UK a couple of years back.

But as the cost of there conversion mini starts at 79K i would presume all the parts to do the conversion would be knocking on at least 30-40K?
i have seen some other information about the swind e motor and they do have to cut into the rear of the subframe and there is some extra brackets required for mounting points.

the only photo ive seen on the internet with the motor in the subframe is this one below.


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what will you be using the mini for? if you are going to go for track use then an LSD will help. Otherwise its not really required.
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ive been contemplating creating a battery box that would locate into the rear subframe, and delete the original 12v battery box thats in the boot floor.
Ive had a quote from electric classic cars in the uk as they import the LG Chem battery cells but they are far too pricey so lookign at the mitsubishi outlander battery pack or the vw hybrid battery pack.
With my old mini decades ago I threw the rear subframe away - instead I used a single bar across the back that carried the rear swinging arms and used coil over shocks with some reinforcing of the rear shock mounts - not a lot is needed the shock absorber peak loads are already higher than the spring peak loads
This gets shot of a rust monster and will give lots of space
I fitted a couple of these "beam axles" over the years and it made the rear end of the mini very skittish, hence why none of the race series currently use them.

Saying that i may look into it on the mini marcos if i can integrate the roll cage into mounting all the rear points and the large battery box im planning. But it will need properly setting up of the corner weights and me cutting and grp'ing some new rear towers in.
one of the issues i have with the swindon powertrain conversion is the new "exhaust tunnel" as in the UK if there are any modifications to changing the bodyshell it can be subject to an IVA inspection, which is something i would like to stay well clear of.
I do think the rear battery box would be ok but i would look at strengthening the boot floor and tieing it in with the rear suspension mounts.

As my conversion is going to be on a mini marcos i have the added fun of it being made out of varying thickness GRP, so will look at building a complete rollcage with the battery boxmounts tied into it.

I must admit for an 89 mini it looks in good shape and at least you dont have to weld a load of new panels in to cut them back out!
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Ive never seen that done before in all my years working on and owning minis. great solution though.
As soon as lockdown is over again in the UK im visiting them for a test drive. They were working with a UK battery specialist for the initial prototypes called MEP Technologies.
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