[WIP] BMW Z3

Tell us about the project you do with the open inverter
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andybpowell
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[WIP] BMW Z3

Post by andybpowell »

This is somewhat overdue but I started posting this project on the Z Roadster forum and it's very time consuming posting on several sites but now that the project is mostly done I thought I'd do a bit of cut n pasting and post a cut down version here

I've been a petrol head forever and this is my first EV conversion but in the past I've done lots of engine conversions and general modification including
Rover V8 into Ford Capri, Turbo 2l Capri, Fiat X19 turbo conversion, Individual throttle bodies, rearmount turbo and Air ride on my Nissan 350Z any way you get the idea
so this is my car a BMW Z3 99 2.0l manual in topaz blue
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The conversion use’s the Nissan leaf em57 motor and inverter originally 80kw with an open inverter control board but I accidently killed the inverter so am now using a 110kw motor and inverter and originally I had 2 BMW 530e 9kwh battery packs but have since gone over to 20kwh’s (10) BMW X5 8s modules Battery management is a modified version of SimpBms controlling standard 16s bms slaves with an adapter board to interface with two 8s battery modules I didn’t design this board it was designed and shared with me by @arturk (many thanks)
He used these in his Jag conversion and the charger is from an outlander the bodywork was good but the side rocker panels (cosmetic outer sill) were a bit worse for wear though the structural sills underneath were excellent with very minor rust
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I managed to get the outer sills from BMW but they were not cheap and come unpainted here they are all painted and fitted ready to start conversion. During this conversion I have also replaced all of the suspension, brakes and bushes
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This is the leaf motor/inverter and half of the gearbox casing this worked out really well and meant that I didn’t have to use a really thick adapter plate to mount it to the BMW Getrag gearbox


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I made up an alignment tool to keep them aligned then did the usual for the motor to gearbox adapter welded the clutch disc center to the leaf gearbox input shaft On the first trial fit of the motor/inverter I realised the steering shaft wasn’t going to clear the differential part of the leaf gearbox housing
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So I introduced it to my milling machine
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I then welded up the cut end to strengthen it back up and stop the casing filling up with crap off the road. No more clearance issues
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I then made up a template of both of the mounting faces using a combination of custom made transfer punches and scanning using a camera attached to my CNC mill
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And transferred it to a ½” ally plate and here it is attached
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Re: [DRIVING] BMW Z3

Post by andybpowell »

The motor mounts were made from steel box section with reinforcing tube welded in where the mounting bolts go through
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The front battery box sides are made from welded 3mm aluminium
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And if I remember correctly the bottom and the middle cooling plate are 8mm ally all held together with studding and a top plastic plate that the contactors are mounted to the top cover I made from fibreglass
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And here it is going into the car
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It’s been through some evolution since this picture was taken it now has 2 BMW oem connectors one of which goes to the inverter the other goes to the rear battery pack that and I now have ten BMW 8s modules instead of the six 16s
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I made the rear pack cover from fibreglass the same as the front
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The power steering is the standard Volvo/Vauxhall electric pump speed controlled via canbus runs at low speed in neutral then ramps up to max at idle on drive reducing with road speed
Brakes are again pretty much the standard VW/Audi vacuum pump with a vacuum sensor and controlled by my own vcu
I have a ptc heater setup using a esp32 interfacing with the standard bmw controls
For the control side I originally made separate boards to control charging, bms, contactors, inverter and vehicle interfacing over the year that this project has taken that has also evolved into my version of tom’s simpbms with the control lines moved to canbus and my own VCU with 3 canbus’s one to the bms, one for the inverter, charger and powersteering and one for the vehicle canbus it also controls the brake light, reverse light, brake booster, ign and powersteering relays, power to the bms and charger/dc to dc, all of the vehicle control signals brakes, accelerator, DNR and also monitors the charger socket
Also In the cabin I have a Nextion Touchscreen display which gives me information on bms, charging, temperatures, motor speed, current etc also allows me to change power settings for different driving modes
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And the most important part the badge
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As you can guess this write up is somewhat condensed and there have been many trials and tribulations but as it stands the car is my daily driver fully legal and re registered and mot’d as electric and no road tax. for now anyway
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:)
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Re: [DRIVING] BMW Z3

Post by andybpowell »

just a little update to try to get an actual properly finished project
I've now re trimmed the boot
IMG20230704121858.jpg
IMG20230704113008.jpg
IMG20230712153245.jpg
IMG20230901132914.jpg
:)
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Re: [DRIVING] BMW Z3

Post by andybpowell »

As per previous post I've also finished up the engine bay
IMG20230417105329.jpg
IMG20230828162522.jpg
:)
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Re: [DRIVING] BMW Z3

Post by andybpowell »

for continuity with this build thread I've cut this post from another thread

Well I got bored with looking for someone who has actually used a lexus is/gs 300h l210 transmission I'm sure people have but nobody's being very forthcoming with any details so I'm just going to do it myself
So I've ordered an is300h l210 transmission, inverter, Zombieverter and an Is300h propshaft this is going to replace the 110kw leaf motor/inverter and getrag gearbox in my Z3

most of the parts should arrive this week and I'll get it working on the bench first.
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Re: [DRIVING] BMW Z3

Post by Alibro »

:) Nice work.
I need a bigger hammer!
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Re: [DRIVING] BMW Z3

Post by andybpowell »

Having done 500 electric miles in the car I've never been quite happy with keeping the standard gearbox it has 120 odd thousand miles on it and had no oil in it when I checked it shortly after buying the car, the electric motor tops out at just over 10,000 rpm at which point the gearbox is screaming also I wasn't 100% happy with the coupling that I made I could fix both of these things relativly easily but I like a challenge so I'm replacing it all with a lexus is300h hybrid transmission there is a slight weight reduction about 10kg but the weight will be moved further back towards the center of the car no coupling between motor and gearbox as it's all one unit and more room up front so I can re fit the original 12v battery but in the front, I had to fit a much smaller motorbike battery in the boot after I fitted the rear HV battery pack due to lack of space and the final and most important reason is because I'm just playing and I want to ;)
I've already ordered the new transmission, inverter, Zombieverter and a lexus propshaft to cut n shut and I may or may not have spent a big chunk of money on another battery told the wife and she said "oh good then I can tell you what I just spent on egyptian cotton for the bed" :wtf:
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Re: [DRIVING] BMW Z3

Post by andybpowell »

Most of my new parts arrived today, lexus 300h inverter
IMG_2724.JPG
and matching transmission complete with, I was going to say clutch but it's not it just looks a lot like one it's just a coupling
IMG_2726.JPG
and the wiring loom
IMG_2727.JPG
I've already stripped it and this is all I needed of it o_O
IMG_2729.JPG
it was worthwhile as the parts to make these bits up would have cost me more than I paid for the whole loom
:)
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Re: [DRIVING] BMW Z3

Post by andybpowell »

Also I just wanted to say that in preparation for this swap from leaf to lexus I have sat and watched all of Damien's relevant videos and once you have the relevant components in front of you his explanations about how they work and how to connect them make complete sense he's done a bloody good job there and having seen the information that he has put out there I have a better appreciation of his frustation at people asking the same basic questions when they obviously haven't looked for themselves they just want the answer given to them on a plate don't get me wrong I'm not perfect I've done the same thing myself but not because I can't be bothered to look but because there's just so much information it's hard to find the one little bit you need like looking for a needle in a haystack as the saying goes anyway I'm rambling it's just an observation ;)
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Re: [DRIVING] BMW Z3

Post by barracuda816 »

Great looking build. Some beautiful work there.

Really interested in the l210 transmission. Have you planned for the gearing? Are you going custom diff or is the max speed not going to be an issue?
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Re: [DRIVING] BMW Z3

Post by andybpowell »

barracuda816 wrote: Wed Sep 20, 2023 12:36 pm Great looking build. Some beautiful work there.

Really interested in the l210 transmission. Have you planned for the gearing? Are you going custom diff or is the max speed not going to be an issue?
speed isn't an issue but there are various gearing options with the Z3 diff and mine needs changing or rebuilding anyway so I'll decide once it's in
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Re: [DRIVING] BMW Z3

Post by Alibro »

Is the Z3 gearbox common with other BMW models? Just wondering as replacing the gearbox might be a cheap easy way to keep it on the road.
Then you could use an old chassis to sort out the fabrication of mounts etc while still driving it.
I need a bigger hammer!
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Re: [DRIVING] BMW Z3

Post by marcexec »

Fair play taking the plunge on this and sharing. Following with interes as I have a W201 here that's waiting to be a mid-life-crisis project...
Would you mind (please don't take offense!) to add a bit more punctuation or line breaks? It's probably because English isn't my first language but I had to re-read your longer texts to actually understand :)
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Re: [DRIVING] BMW Z3

Post by andybpowell »

marcexec wrote: Thu Sep 21, 2023 10:08 am Fair play taking the plunge on this and sharing. Following with interes as I have a W201 here that's waiting to be a mid-life-crisis project...
Would you mind (please don't take offense!) to add a bit more punctuation or line breaks? It's probably because English isn't my first language but I had to re-read your longer texts to actually understand :)
Don't worry I'm not taking offense but the reason that it's like that is because I have Dysgraphia so what I usually do is type it out then go back over it 2 or 3 times to correct/add punctuation it still won't be perfect but good enough but if I'm rushed it comes out like that
Again let me assure you that I'm not offended your comments are perfectly legitimate :)
You should see my handwriting :lol:
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Re: [DRIVING] BMW Z3

Post by andybpowell »

Alibro wrote: Thu Sep 21, 2023 9:11 am Is the Z3 gearbox common with other BMW models? Just wondering as replacing the gearbox might be a cheap easy way to keep it on the road.
Then you could use an old chassis to sort out the fabrication of mounts etc while still driving it.
The gearbox is reasonably common but keeping it on the road isn't an issue for me
also I don't have space to work as it is without having another one in the way :lol:
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Re: [DRIVING] BMW Z3

Post by marcexec »

andybpowell wrote: Thu Sep 21, 2023 11:49 am Don't worry I'm not taking offense but the reason that it's like that is because I have Dysgraphia so what I usually do is type it out then go back over it 2 or 3 times to correct/add punctuation it still won't be perfect but good enough but if I'm rushed it comes out like that
Again let me assure you that I'm not offended your comments are perfectly legitimate :)
You should see my handwriting :lol:
No worries then! A bit of neurodiversity never hurt a community and truly appreciate your efforts on and off the keyboard mate!
Maybe voice is easier, so how about you just talk us through on a video of you driving 0-60ing the beemer with the IS300h? :P
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Re: [DRIVING] BMW Z3

Post by Alibro »

andybpowell wrote: Thu Sep 21, 2023 11:49 am Don't worry I'm not taking offense but the reason that it's like that is because I have Dysgraphia so what I usually do is type it out then go back over it 2 or 3 times to correct/add punctuation it still won't be perfect but good enough but if I'm rushed it comes out like that
Again let me assure you that I'm not offended your comments are perfectly legitimate :)
You should see my handwriting :lol:
Occupational hazard for techs. :(
Because of dyslexia I couldn't spell to save myself so spell check is a Godsend for me. I still have to read and rewrite everything several times too. :?
I need a bigger hammer!
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Re: [DRIVING] BMW Z3

Post by andybpowell »

Hmmm I think something's missing
IMG_2731.JPG
from 99% finished to lets start again my wife says I may have mental health issues but I just like a challenge
Climbing out of the engine bay with a 40Kg gearbox was a challenge getting the 90Kg one back in may be a little more challenging

here they are next to each other going to have to shorten the propshaft by about 150mm
IMG_2730.JPG
:)
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Re: [DRIVING] BMW Z3

Post by m.art.y »

Hi, Andy, what would your thoughts be on another option - to use a modified Leaf gearbox (like Clipper cab has done in the photo attached) to drive the rear diff? Would that be a viable option and would it allow to slide the Leaf stack further in into the gearbox tunnel to win some space in the engine bay?
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Re: [DRIVING] BMW Z3

Post by andybpowell »

m.art.y wrote: Fri Sep 22, 2023 7:35 pm Hi, Andy, what would your thoughts be on another option - to use a modified Leaf gearbox (like Clipper cab has done in the photo attached) to drive the rear diff? Would that be a viable option and would it allow to slide the Leaf stack further in into the gearbox tunnel to win some space in the engine bay?
wouldn't gain me anything to be honest would actually move the leaf motor to the side and make space worse but in all honesty I'm just playing and like the idea of the 300h as I cant find any running projects with one in :)
it's very cool though
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Re: [DRIVING] BMW Z3

Post by andybpowell »

Things are moving along nicely the lexus propshaft arrived and it has been cut along with the Z3 one but not to exact length yet as I don't know what that is
IMG20230924172922.jpg
I've made up an adapter plate to mount the lexus transmission to the Z3 gearbox mounting, I've made it in 6mm aluminium for now I might end up making it in steel though
IMG_2734.JPG
I took the old gearbox out by hand it weighed about 40Kg the new one weighs about 90Kg so is not going back in the same way
IMG_2737.JPG
and here it is like magic, it was nothing like magic to be honest it was a pain in the arse would have been quite straightforward if I wasn't doing it on my own
IMG_2739.JPG
With the rear gearbox mounting bolted up I've got a calibrated lump of wood at the front and the gearbox output shaft and propshaft are lined up perfectly only took about 2 hours of sodding about
IMG_2743.JPG
IMG_2742.JPG
I've actually measured for the hybrid propshaft but I'm missing the flexible front coupling so can't do anything until I get one or at least get measurments for one
:)
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Re: [DRIVING] BMW Z3

Post by andybpowell »

Got the hybrid Lexus/BMW prop welded up today and before anyone asks it was clamped in a jig I made to tack it together
IMG_2749.JPG
And here it is fitted
IMG_2750.JPG
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I'm going to have to move some of the cables as there's not much clearance
IMG_2754.JPG
not sure if this is just going to be for testing depends on vibration as it's not been balanced

:)
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Re: [DRIVING] BMW Z3

Post by rstevens81 »

Depends if the actual lever does anything I guess, as if you can request negative torque then it's sort of pointless
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Re: [DRIVING] BMW Z3

Post by andybpowell »

It won't be used just locked in position but it's still uncomfortably close to the charging cable
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Re: [DRIVING] BMW Z3

Post by andybpowell »

since I'm waiting for parts I got some of the smaller jobs done today
Made up spacers to hold the motor coupling to the front plate
IMG_2761.JPG
IMG_2760.JPG
most people seem to take it apart but I'm going to leave it intact and use the standard m8 fixing holes

also made up some brass posts to connect HV to the inverter
IMG_2763.JPG
:)
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