83 replies to this topic

[Tremelune]

Howdy! I picked up a 1992 JDM Mini that I'm in the early stages of converting to electric using Nissan Leaf batteries and motor. Current plan is to slap everything together as simply/cheaply as possible and get it street-legal in California, which could be rather involved (so I'd like to get that out of the way before I focus on niceness). I'm gonna ditch the Mini motor and transmission, and put the Leaf in their place, driving the front wheels directly through it's 8:1 reduction gearbox.

 

This forum seems to get the most traffic, so I thought I put the more Mini-centric aspects of the build here, reserving the EV nitty-gritty for the conversion forum. I will definitely need knowledge of suspension setup and subframes when all is said and done! I'm hoping to avoid purchasing the more spacious Minitec subframe, because, well, it's USD$3k. I'd also like the option of sticking with standard Mini suspension components, as there seem to be many more options than the somewhat non-standard Minitec stuff. This is the only Mini I've ever driven, and it's a blast. I don't want to ruin the handling or the factory looks.

 

First order of business is taking the car apart. I'm hoping to have the front subframe modified to fit the Leaf motor with custom drive axles, but space is limited...I'm gonna drop it and measure for feasibility. Is there anything I should do before taking the motor out in case I sell it? My plan was to check compression, get a video of it driving, and clean it up a bit. It's nothing special; runs well, leaks a bit. It's fairly rare in the States, but so are Minis in general...

 

Wish me luck! This could be disastrous.

 

Edited by Tremelune, 28 September 2019 - 06:52 AM.

[Tremelune]

I took the opportunity to get some rough corner weights of the car to help me figure out where to put batteries when the time comes. I expect to put at least 200 lb of batteries behind the front seats (400 lb total), so the weight distribution of the car might change significantly and I wanted to know what my real baseline was. It wound up pretty similar to what my internet searches said:

 

Corner weights (empty gas tank, no driver):

495 505

300 275

Front 1,000 (64%)

Rear 575 (36%)

Total 1,575

 

Corner weights (empty gas tank, 150 lb driver):

510 565

315 335

Front 1,075 (62%)

Rear 650 (38%)

Total 1,725

 

Depending on where there is space (and how much effort I'm willing to expend), I can kind of put batteries wherever I want. My plan was to aim for 50/50 with driver, erring on the front-heavy side. I expect the car to get 100-200 pounds heavier total, but with luck, most of it will be between the axles.

 

Here's a shot of my scale setup...I just used four high-weight bathroom scales, some 2x4s, and some ziplock bags full of grease to help level the suspension when the car is lowered. Not particularly accurate, but well in the ballpark.

 

Edited by Tremelune, 28 September 2019 - 06:48 AM.

[Vinay-RS]

Following this build. It sounds like an interesting project. Please share the technical details of the conversion too, it'd be nice to read about how you go about the process. There are a few folks over here who want to build electric powered Minis, but I don't think our power grid is ready for it.  

[DeadSquare]

Oh my !

 

I know some Americans are big, but fancy needing four scales in your bathroom, Lol.

 

What shape and dimensions are the batteries, and how many will there be ?

Edited by DeadSquare, 28 September 2019 - 04:27 PM.

[Tremelune]

Batteries are the standard Leaf pack—48 modules at about 9x12x1" and 8 lb each. First draft is to just shove two "rows" of 24 into the back, each about 36" long and 200 lb.

 

[DeadSquare]

 A Mini doesn't really like much weight behind the rear axle line before the handling becomes "nervous"

 

Two full fuel tanks and a couple of extra spare tyres is noticeable on a wet road, and without weighing items, I shouldn't think that 3 wheels, two tyres and a battery come to 200 lbs.

 

You could buy an inch  X  9" wide plank, cut it in lengths and see how many would fit under the back seat, rear bins, under the front seats and as many as you could get, behind the radiator grill.

[Tremelune]

There might be an opportunity to put half the batteries in the engine bay to keep the weight forward, but I suspect that awkward handling could be cured by changing the spring rates front and rear to compensate for the weight change. I can't wait to solve handling issues, 'cause I have a looong way to go before they're the problem I'm facing...

 

Right now I'm staring at removing the engine. I've found various threads about it, and they're all like "unbolt these things and yank it out!" It seems a bit trickier with the JDM cars, 'cause they have air conditioning and other inconsistencies...Or maybe I'm just ignorant. I'm looking at the procedure for removing the drive shafts and it has me wondering if I shouldn't just lower the whole subframe out instead of trying to pull the motor from it...It seems very likely that I'll need to replace it anyway. I wish I knew if the Minitec subframe was a handling upgrade from stock, or if it's just a compromise to fit a larger motor...

 

How do I drain the coolant?? I can see the lower hose on the back of the radiator, but I can't image how I could get a hand down there to unscrew the clamp and yank it from the rad! Any chance I can just pull it all out with the motor? Every path I see involves coolant just kind of dripping everywhere, missing the catch pan...

 

Brake booster??

Edited by Tremelune, 29 September 2019 - 04:19 AM.

[DeadSquare]

The cars were made by lowering the body onto the engine in the subframe. Remember to undo the earth strap and remove the clutch slave cylinder.

[Tremelune]

I managed to get the axles out, removed the AC condenser, removed the exhaust (besides the headers), pulled the shifter and connections, and I used a turkey baster to get enough coolant out that I could disconnect the heater lines that went to the bulkhead. Hopefully I won't have to drain the coolant at all!

 

My current struggle is with the brake servo. I've read to "flip it up out of the way" but it's not clear how I can do that with it still attached to the hard brake lines. I'd rather not do that if I can avoid it, as I'd like to have brakes in case I need to tow the car. Although...I don't really need brakes for that, and I think I need to disconnect the lines to remove the subframe, which I'll have to do eventually...So maybe this is a solved problem. Buuut, is there any way to get the servo out of the way without disconnecting the hydraulics? Do I just bend them and hope they don't fatigue?

 

[Tremelune]

Welp, I just pulled the hydraulic lines and got the servo all the way out. I took a shot of the clutch slave connection, just 'cause it's hard to see. That's gotta come off. The upper and lower engine "steadies" were straightforward, though I did need a drift to get the top one out from under to avoid unbolting it from the engine.

 

It seems like the only things remaining are the fuel lines to the intake, some other random hoses I don't understand, and one weird hose/wire that screws into the block of the motor. Anyone know what that is or what will happen when I undo it? Anyone know the best place to disconnect the fuel lines?

 

After that, the plan is to get some straps around the engine, unbolt the 8 subframe bolts, hoist, look, hoist, look, etc. Anything I'm missing? I found the "AKM7169" manual, but it's pretty light on engine removal details...

 

 

 

[GraemeC]

Personally I would remove the manifolds, either way, disconnect the fuel lines where the rubber pipes join the solid ones that go to the throttle body.
The two pipes you show - the upper one is the oil feed to the filter, the lower one is to an oil pressure gauge on the dash.

If you are lifting the car of the subframe and engine you will also need to remove the battery cable and the speedo drive cable. And if you haven’t already disconnect the steering rack from the hubs. Obviously all wiring will need to be disconnected.

[rkde]

I have been looking at this type of thing for another classic I have and I think that the outlander PHEV rear motor may actually be better for the mini conversion - really worth a look as its a powerful enough motor and small enough for the mini with the drive shafts almost perfectly in the correct place

[Tremelune]

I have been looking at this type of thing for another classic I have and I think that the outlander PHEV rear motor may actually be better for the mini conversion - really worth a look as its a powerful enough motor and small enough for the mini with the drive shafts almost perfectly in the correct place

 

Interesting. How would I got about attaching drive axles to the rear wheels?

[Tupers]

I think rdke is suggesting using the rear hybrid drive unit (electric motor and gearbox) and fitting it in the front of a Mini rather than the rear of the outlander.

[Tupers]

If you scroll down here there’s an image of the rear drive unit in a Highlander. Although it’s a bit hard to gauge its size at first glance I’d say it looks like it could be made to fit.
https://allwheeldriv...hlander-hybrid/