[DRIVING] - Z3(00)

Tell us about the project you do with the open inverter
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[DRIVING] - Z3(00)

Post by bobby_come_lately »

After a few(!) glasses of wine yesterday, I took the plunge and actually bought the car we're going to convert. Which means I guess the dabbling phase is over and I ought to post something here.

The 'we' is my increasingly car-obsessed 10yo daughter and me. She's both the inspiration and the motivation for this project. And the learning she will get helps me to justify spending the money on it.

The plan is initially to build an electric BMW Z3. To that end I broke all the rules yesterday and bought one off Gumtree, unseen and with very little investigation, from the other end of the country (I'm in Manchester (UK), the car is in Cornwall). In my defence, it was only £600 so even with shipping I'll be into it for less than a grand. With a bit of a tidy up and some minor repairs, I'm fairly confident we could sell it for more than that.

But if all goes to plan, it's going electric. Right now, I'm playing with a Prius inverter (stripped down and just waiting on a board from Damien) and Outlander front motor but increasingly think that might just be for learning. The Bexus route is very attractive and if it would fit in the tunnel then a 300hp roadster sounds like a lot of fun.

Battery-wise I want to experiment with the packs from the 330e. Hoping between the work on the i3 and the 530 packs, someone will have nailed down the CAN messages for those soon. Need to measure up but wondering if I could squeeze one of those in under the bonnet - especially if I go down the Lexus route. That would make for a neat (and cost-effective) initial conversion, with the option of adding more packs at the back of the car down the line.

Once we have a working car, then the aim is to do a body conversion using the Tribute Z300s kit. Daughter rather likes the 60s-style roadsters and I think she has excellent taste :-)

Trying to keep it simple for now though: can we make a car move under battery power?

Documenting everything I do and have learned over here - so far mostly about the Outlander front motor: http://projects.tomcheesewright.com/ev-project.html
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Re: Z3(00)

Post by Kevin Sharpe »

Great project :D
bobby_come_lately wrote: Sun May 17, 2020 5:35 am Documenting everything I do and have learned over here - so far mostly about the Outlander front motor: https://projects.tomcheesewright.com/ev-project.html
Can you please post some pictures/information here not just via a third party website? We don't want to break the thread when the host inevitably disappears in the future (or stops working like today).
Screenshot 2020-05-17 at 09.37.15.png
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Re: Z3(00)

Post by mike77cos »

Where in Cornwall have you bought it from?
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Re: Z3(00)

Post by bobby_come_lately »

Pelynt - near Duloe? Can't say I know the area!
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Re: Z3(00)

Post by bobby_come_lately »

Kevin Sharpe wrote: Sun May 17, 2020 8:40 am Great project :D
bobby_come_lately wrote: Sun May 17, 2020 5:35 am Documenting everything I do and have learned over here - so far mostly about the Outlander front motor: https://projects.tomcheesewright.com/ev-project.html
Can you please post some pictures/information here not just via a third party website? We don't want to break the thread when the host inevitably disappears in the future (or stops working like today).

Screenshot 2020-05-17 at 09.37.15.png
Absolutely - will repost stuff from there. My bad on the link - so used to typing https I forgot I don't have a certificate on this site yet: http://projects.tomcheesewright.com is the right link.
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Re: Z3(00)

Post by mike77cos »

I'm from Cornwall (St Austell), there was one near me for around the same price before lockdown, but I don't think it's the same one.
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Re: Z3(00)

Post by bobby_come_lately »

Let's start with the motor...
Here are the specs from the original ad:

70 kW EV Motor
AC Motor
Input voltage 400V
Type 3 Phase synchronous perm magnet brushless
Resolver: SIN COS resolver
RPM 14000rpm max
The motor comes from a Mitsubishi Outlander PHEV (plug-in hybrid electric vehicle). Based on a video from ZeroEV and looking at the shape and configuration of the motors from the Outlander PHEV site, my current belief (though this is still up for debate) is that this motor has maximum output of 60kw with a rated output of 25kw and 137Nm of torque. Its big brother, the rear motor has 70kw, at least on the latest edition of the PHEV. I originally thought this was one of a pair of motors connected to a gearbox at the front but the other, very similar looking, unit is actually a generator (though likely can also be used as a motor).

Why did I choose this motor? Because I was watching it on eBay and the clever people at Second-Life Batteries who were selling it sent me a special offer at a moment of weakness. They only knocked £25 off the price (in the end it was £445 including shipping), but that was enough for me (with my daughter's encouragement) to push the button on this project.

Is it the right motor for the job? I honestly don't know enough to answer that yet. On the plus side, it's relatively small (roughly 450x300x250mm at its widest points - including the full length of the shaft (snigger)) and light (about 27kg). It's also powerful enough in theory. I saw a rough figure over on the DIY Electric Car forums suggesting that you need 35kw per 1000kg of car? The donor car is fractionally over 1000kg and will likely remain around that with the relatively small battery pack I'm planning to include, once we've shed the combustion engine and all its ancillaries. So in theory this motor has plenty of power.

Negatives? I'm worried that some of those KW come as a result of its relatively high speed. I don't really want to be driving a combustion engine gearbox at 14,000rpm or I might find myself with gears in my lap. We shall see. Also, no-one has yet made an adaptor for the splined shaft on these motors to allow them to be bolted onto the flywheel from a combustion engine. If I'm going to mate this motor up to the gearbox from my donor car (as is my plan), then I'll need to design that and get it fabricated, along with an adaptor plate to bolt the two together.

Finally, on the negatives, I see some much smarter people than me on this forum saying that these motors have a lot of 'quirks'. Controlling it could be a challenge and I am going to be rather reliant on others overcoming these challenges to make this work.

[PS: Now that I (think) I know what I have, I'm a little concerned about the power output. It could be a little puny in both horsepower and torque. We shall see.]
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Re: Z3(00)

Post by bobby_come_lately »

mike77cos wrote: Sun May 17, 2020 8:52 am I'm from Cornwall (St Austell), there was one near me for around the same price before lockdown, but I don't think it's the same one.
There are a lot of slightly crusty ones around at ~£1000. My hope is that I can get a few quid back selling the engine etc but it's the worst one - the 8v 1.9 from the 1999 refresh. Only 114bhp.
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Re: Z3(00)

Post by bobby_come_lately »

The Outlander motor has two multi-pin connectors on it, one with eight pins and one with six. Fortunately, Second Life Batteries also supplied me with the plugs for these connectors, and they still had some cut off wires from where they were installed. Four wires coming from the 6-pin connector and seven from the 8-pin connector.

A little googling brought me to a Russian online service manual for the PHEV, which contained heaps of useful information. To save you the ads for Russian brides, and because I think it is wrong in places, I've tried to aggregate that information and improve on it here.

6-Pin Connector

Outlander PHEV 6-pin motor connector

Written on this connector I found the numbers "12303". A little googling revealed that is used to connect the throttle pedal on Toyotas and Subarus. The first search results that came up all led me to the US for replacement parts at exorbitant cost. But a trip over to AliExpress turned up some bargains. In the end I bought two (just in case) for just £1.70 each including the pins and the cable shrouds that seal then junctions.

The six connections here are to three temperature thermistors buried in the body of the motor. One measures the U-phase coil temperature, one the W-phase coil temperature and one the general oil temperature via a separate thermistor. Here are the pins for measuring each of those:

Pin 11 (sticking with the numbering on the service manual): GTH1 - temperature in the U-phase coil (+ve)
Pin 12: GTH2 - temperature in the W-phase coil (+ve)
Pin 13: TH0 - oil temperature thermistor (+ve)
Pin 14: GTG1 - temperature in the U-phase coil (-ve)
Pin 15: GTG2 - temperature in the W-phase coil (-ve)
Pin 16: TG0 - oil temperature thermistor (-ve)
All pretty straightforward, right? Here are the resistance ranges you should expect across those temperature sensors (connect your multimeter to the -ve and +ve pins for each sensor).

At -20°, you have my sympathies, and you should see 400-600kΩ
At 0°, you should see 140-200kΩ
At 20°, you should see 55-70kΩ
At 40°, you should see 23-30kΩ
My 6-pin connector was only wired for the phase coil temperature sensors, though I may add in the extra wires if I can find out what connector this is. I got it hooked up to my multimeter and sure enough, I saw exactly the above. My home automation system tells me it is 21.4° in my office and I read 65kΩ and 65.2kΩ across the two coil thermistors. So far, so good.
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Re: Z3(00)

Post by bobby_come_lately »

8-Pin Connector

Here's where things get a little more complicated - at least for me, as this was new territory. The 8-pin connector is for the resolver.

Pin 1: R1 (sticking with the naming from the manual again) - the first connection for the exciter coil
Pin 2: S1 - the first connector for output coil 1 (perhaps we should rename this S1-1? looks like this is a standard naming convention so will stick with it)
Pin 3: S2 - the first connector for output coil 2 (S2-1)
Pin 4: R2 - the second connection for the exciter coil
Pin 5: S3 - the second connection for output coil 1 (S1-2)
Pin 6: S4 - the second connection for output coil 2 (S2-2)
Pin 7: GGND - earth connection to the ECU

Again the manual helpfully supplies some resistance values for checking the condition of the resolver coils.

Between R1 and R2, you should see 29-38Ω
Between S1 and S3, you should see 70-92Ω
Between S2 and S4, you should see 60-83Ω

Checking mine I saw 37.3Ω on the exciter coil, 86.1Ω on the first coil, and 78.4Ω on the second. All good. (Phew).

BTW 8-pin connector is marked as 12520. As far as I can tell this is listed in the Toyota parts catalogue as 90980-12520. This will set you back $20 and $60 shipping from the US, but AliExpress comes to the rescue again. I bought a couple at £3 each including pins and shrouds, with just a couple of pounds paid for shipping.

So, as I understand it, hooking up S1 and S3 should give me SIN and S2 and S4 should give me COS, which both feed back into the inverter.
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Re: Z3(00)

Post by arber333 »

I think there is a possibility you will be able to tun it natively with Outlander inverter soon. There is a project of CAN controller for rear and front motors. Just command torque and some aux signals... I can't wait to see that in action.

I think 30kw is enough for 1t car level driving at highway speeds. Input a hill and power demand rises to 50kw which is still enough for this motor. It will not win any competition but it will drive. It will be easy on the battery...
Yes motors are 10pole so they have high torque on the left side of the curve. I think it would be good enough to drive up to 4000rpm when you would run out of voltage and have to shift or go into weakening.
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Re: Z3(00)

Post by bobby_come_lately »

That's really useful - thank you. I'm planning to keep the 5-speed box and just bolt the motor to the front of that so plenty of gearing. Weakening shouldn't be a problem at motorway speeds in high gear with little torque needed?

This reinforces my plan: get up and running in this configuration as a learning exercise then maybe come back to the Lexus set-up down the line.
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Re: Z3(00)

Post by bobby_come_lately »

Bit more on that motor re: orientation and cooling.

It wasn't immediately obvious to me which way the motor should be oriented, so back to the service manual I went. The diagram (below) was very helpful (forgive my atrocious drawing skills over the top of it). Once you realise which way the motor goes, it becomes pretty obvious: there's a lifting eye for craning it in and out at the top, and the oil pipes are fixed at the top and bottom.

It was while looking at the cooling system diagram that I realised why I couldn't match my motor to lots of the pictures very easily. What this shows is TWO motors (or a motor and a 'generator') mounted side by side into a gearbox. Hence the split inputs into the cooling system (9) and the pipe (14) that connects the cooling output of one motor to the input in another. Most of the diagrams in the service manual show everything as part of this larger assembly.

The good news is that the oil cooler here is pretty small. I count seven rows, so a nine or ten row cooler should give plenty of headroom, even if we're working the motor hard. We will need an electric oil pump (I picked up a used MOCAL unit for £50), and some pipes to hook it all up. The outside diameter (o/d) of the barbs on the motor is 10.4mm according to my cheap calipers. I'm guessing this means 10mm internal diameter (i/d) for the pipes for a snug fit. Plus some spring or jubilee clips to keep it all tight. There's no reservoir. As the diagram shows, you just top the level up straight into the filler plug...which is on the other motor to mine. So I'll need to rig some sort of filler neck with a t-connection and a non-return valve spliced in above the entry point in the top of the motor casing. At least I have the drain plug and the fill level plug.

Fluid-wise, it looks like the specification is for CVT fluid - "MITSUBISHI MOTORS GENUINE CVTF-J4". You can find a few CVT fluids that claim to meet this spec at around £7/litre.
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Re: Z3(00)

Post by bobby_come_lately »

Bit of a motor update. I couldn't find any diagrams of the mounting points for the PHEV front motor. At least, not ones with measurements. So I set about making a simple CAD model of the motor face in order to map out the bolt pattern.

Without a 3D scanner (a hole in my toolkit I would very much like to fill), my best option (other than maybe a paper template) seemed to be to try to measure the rather uneven surface with calipers and a ruler and transfer those measurements into Fusion. I then 3D printed a simple template with a hole for the single dowel and plugs for the two M8 threaded holes and four 11mm holes. After about ten iterations of the 3D printed model, I finally had a model that fitted accurately - at least to within a few fractions of a millimetre (note - this is not the one in the picture below). Good enough for government work, as Mr Bauer would say.

I have a little more testing to do but then I'm happy share my template with others looking to use this motor. When the car arrives and we have removed the gearbox, I will map the motor mounting holes against the ones on the gearbox and design up a full adaptor plate. Then I can sort out the adaptor between the splined shaft and the BMW flywheel. Looking at places to get that machined at the moment.
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Re: Z3(00)

Post by Kevin Sharpe »

bobby_come_lately wrote: Wed May 20, 2020 6:12 am I have a little more testing to do but then I'm happy share my template with others looking to use this motor.
Thank you! :)
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Re: Z3(00)

Post by bobby_come_lately »

Finished soldering up test cables for the motor and throttle last night. Probably not necessary for testing, but using some of the shielded twisted pair I bought to use in the car where there will be lots of EMF noise. Replicating some of the stuff from the blog for posterity here.

##

I'm planning to use a BMW 1-Series Throttle Pedal, though I think they are fairly similar across a number of cars. This cost me £10.49 inc shipping from eBay, which seemed very reasonable. My unit came in good condition with the connector plug attached and some decent length tails on it.

I found the pin out information on a forum post on a racing simulator site (https://www.isrtv.com/forums/topic/2171 ... -throttle/) of all places:

Pin 1: GND 1 - Brown/Yellow (apparently brown and green on the E46 pedal)
Pin 2: GND 2 - Brown
Pin 3: VCC 2 - Yellow/Green
Pin 4: SIG 1 - White
Pin 5: VCC 1 - Yellow
Pin 6: SIG 2 - White (apparently white/green on the E46)

From this I could tell that the pedal probably has two position sensors that each take an input voltage and return a signal. But I wasn't sure if it was resistive or encoder-based at first. A bit of googling told me the electronics expect 5V on a modern BMW so I hooked the pedal up to the bench power supply and a multimeter and took some voltage readings (i.e. 5V to VCC 1, Ground and multimeter ground to GND 1, and multimeter to SIG 1, then repeat for SIG 2). My bench power supply is actually an old PC PSU (I do love to recycle) so it isn't adjustable and doesn't give me exactly 5V. Measured at 5.13V while testing.

Here are the results:

SIG 1
Throttle at rest: 0.73V
Throttle at full travel: 4.00V

SIG 2
Throttle at rest: 0.36V
Throttle at full travel: 2.02V

So, the output of SIG 1 has exactly twice the resolution of SIG 2. Guess there are two for safety reasons? [this website confirms that - https://www.picoauto.com/library/automo ... l-position]. Either way I now know how to get the output of my throttle and feed it to the inverter control board.

Note on the connector: It's a Tyco unit (expensive) but there are nice cheap clones available on AliExpress - search for 967616.
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Re: Z3(00)

Post by bobby_come_lately »

Bit of an update. A counter to my relentless positivity and optimism!

Despite Damien's very good instructional videos I learned this week that I am not good enough at soldering to complete the Prius Gen 3 Kit. Between me and the guy I handed it over to to fix my mistakes, we managed to bork the board completely so a second one is winging its way to him now. At least I feel like I have contributed to Damien's purse, even if he doesn't make much on them.

Means a bit of a delay to the project and particularly that I won't be able to get the motor and inverter running before I start on the mechanicals, which had been my plan. Going to have to take the slightly higher risk approach of pushing ahead with the adapter and plate while I wait on the electronics.

In the meantime, the car is on its way and will arrive Wednesday or Thursday. We have about a 40-point plan worked up for its inspection, repairs, and then disassembly. Looking forward to getting my newly-assembled ESP8266 CAN sniffer on it so that I can start to get my head around that and what it will take to keep the dash instruments and ABS etc happy. Also have an old serial diagnostics cable for the 20-pin BMW connector which I'm hoping to be able to tie into for other diagnostics.

Meanwhile I'm trying to restrain myself from buying some of the bits for my option 2 approach to play with: GS450h parts. Lots on eBay right now and I now have three different people locally offering to do the fine soldering for me. So I may be throwing a little more money Damien's way before long...
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Re: Z3(00)

Post by Jack Bauer »

Good to hear you're getting some help. The new kit went out with ups yesterday morning so should be with you shortly.
I'm going to need a hacksaw
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Re: Z3(00)

Post by bobby_come_lately »

Great - thanks Damien. Looking forward to getting this motor turning!

Things looked up today in any case: the project car arrived. It's pretty much what I was hoping for at £600: cosmetically crap but that doesn't matter as planning to replace most of the body panels. Doors only need a skim of filler before they are repainted. New sills are only £30 a side.

Mechanically and structurally seems - at least on first inspection - to be really sound. Not got under it yet due to pressures of work, but planning to take some time off after next week to really get into it.

Only EV snag I may have hit is how high the bellhousing comes into the engine bay. Was hoping it would sit a little lower so there would be room for the 330e battery pack to sit over the top of the motor. It will fit length and width-wise, just might be too tight in depth. May be able to fit it underneath (which would sit the weight lower - all good) and may be able to re-orient the motor. Lots of investigating to do. But was hoping to be able to avoid having to build a new battery box to save time and money.

Anyway, if anyone wants a BMW fourpot with 'only' 174,000 miles on it, let me know!
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Re: Z3(00)

Post by bobby_come_lately »

Right, update time. Has been a busy couple of weeks work-wise but still managed to make some progress. And I'm taking the rest of this week off to work on the car.

Have fixed the main issues with the car itself. Central locking and power hood just seemed to be bad earth/connection issues and both now function fine. Got diagnostics onto the engine and it confirmed what the high-pitched whistle told me: vacuum leak was the reason for the warning light on the dash. Plus the secondary air pump is knackered and detached from its mountings. And there's a split in the air intake hose that connects to the MAF. All standard stuff and not really worth fixing before I pull the lump out. Engine is high mileage but hoping to get a few quid back for the it and the accessories I don't need.

Have been trying to get my head around the car's use of CAN and I can't really find that I'm going to need to worry much about it. Only concerns are with engaging the active stability control and the ABS, but I can't see that either actually need CAN messages. And neither use CAN to communicate with the dash. In fact the dash seems to be largely old-school with lots of mostly 12v signals for various faults. If anyone knows different I would love to hear (it's a 99 Z3 1.9) but at the moment the plan is to pull the engine next week when the driveway is clear (builders in this week).

In the meantime we're cracking on with the drive unit. The inverter is back from my electronics saviour, soldered up, tested and working. Only one thing seemed a bit off - only getting 26 volts where I believe I should be getting 36 according to the Wiki? But web interface comes up fine.

Test board with all the HV components (including contactors from Jaanus - ta) is mostly wired up - should get that finished today. Have designed some little brackets to hold key switch, direction switch and brake button. One done and one on the printer now.

Talking of 3D printing, I've designed up a new two-part plate to hold Damien's AMPSEAL connector daughterboard onto the Prius Gen3 inverter (attached). This clamps the board and seals against the white silicone on the plug. It draws on Konstantin's initial design but I had to choose between making the plate much thicker or ditching the red sealing ring from the original plug. I went for the latter and will probably put a skim of silicone on when it is fitted finally. There's enough slack in my IDC cable to allow the top of the inverter to be removed with the plate in place. Maybe need a separate thread for 3D printed parts for this inverter?

Few more blanking plates to design and print, including something to seal around the battery connections. I have a pair of Damien's brass standoffs for the battery connections and hoping I can make something to go around those. Resistance of PETG seems to be higher than my multimeter can measure so only issue I can see would be is moisture was trapped around the connectors. Again, if anyone knows different I'd love to hear.
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Re: Z3(00)

Post by bobby_come_lately »

Quick update: turns out the inverter wasn't quite working properly. While the board fires up I couldn't get a sine wave out of it and my dc voltage readings were all over the shop. Damien confirmed via the forum what I feared: it was that 50 pin connector that has been the bane of my project so far.

Now on the hunt for a real electronics professional who can clean up the work of my willing but clearly not-quite-good-enough friendly helper who originally came to my aid. Have found a couple of options locally and just waiting for them to come back to me. If I find I good one, I'll share their details in case anyone else faces the same issues as me.

Meanwhile I may have found a good trade over on the ZRoadster forums from someone who is willing to offer me cash and a 1-series electric steering rack for my old engine, which may solve a problem I hadn't even gotten around to thinking much about yet. If the measurements look within my fabrication ability, that could be a good deal.

So, frustrating week as I hoped to have the motor spinning by now. But I feel like I now know the UI for the software pretty well even if I did learn by the medium of swearing at it. And my pre-charge set-up is working beautifully with my Panasonic pre-charge resistor and Gigavac contactors in place. So once I can get the inverter up and running it should be a matter of plugging it all back in and configuring.

Also made progress on 3D printed parts for the Gen 3 inverter. Have posted current set on a separate thread and am ready to test a three part shroud for Damian's brass battery standoffs. If that test goes well I should be posting that next week.
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Re: Z3(00)

Post by bobby_come_lately »

Have been a bit slack updating here on the rollercoaster that this project has been over the last few weeks. In short, I'm still having issues with my control board and after investigating many other options and there being many false hopes, it appears the issue remains with the 50 pin connector where the is an intermittent short between pin 10 and ground.

It's only intermittent now thanks to @Bigpie who offered to test my board in his rig and rule out human error, and then went on to tidy up some of the soldering on the relevant contacts. The result is that in the periods it has been working I've got as far as getting the motor to vibrate, if not spin.

Back to the repair shop tomorrow to see if they can remove, clean and replace the 50 pin connector, perhaps with one from the stock board.

In the meantime I gave up on my original intention to get the electric drive train running before dismantling the Z3. Most of the front end is off (just waiting on a spot-weld drill) to ease engine removal, and most of the ancillaries are out. Today will get the remaining fluids drained and some other bits removed as long as the weather holds out.

Have ordered the remaining parts for the HV junction box - standoffs/bobbins, copper bar for connections, and the box itself. Not including anything for charging yet but hopefully leaving space to add that in. Also will need glands, conduit and HV cables to finish hooking it all up.

Pedal fitting is pretty much finished. Designed and 3D printed an adaptor to allow me to mount the 1-Series electronic pedal to the old Z3 mounting bracket and really pleased with how that has turned out.
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Re: Z3(00)

Post by bobby_come_lately »

Lots of progress in the last couple of weeks. Then motor runs! The engine is fully out, I've tried two different steering racks, I've changed my plans for the coupler, some of the wiring is in, and the steel for all the adaptors and mounts is ordered.

Let me break that down a bit.

Motor
Thanks to the help of @Bigpie and my local electronics shop, I now have a fully working inverter and a spinning motor using the FOC firmware. LOTS of tuning to do but I don't think it's worth trying to do it with my dodgy old car batteries, so that can wait until I have some real batteries.

Engine Removal
With only one minor mistake (I missed a pin on the gearbox so ripped the shifter out with the transmission - fortunately nothing damaged) and two minor breakages (the plastic heater pipes both got cracked), the engine and transmission came out. Was a fantastic day working with my daughter on everything, who proved she has excellent instincts for all things mechanical. Over the next few days we stripped out the remaining parts like the steering rack (more below) and gave the whole engine bay a really good clean. This uncovered a few spots of rust but nothing serious. Though the X-frame under the engine is not in good shape. Suspect I will have some welding to do there.

Plan is to give it another clean and a coat of paint before reassembling everything. Not original colour and not expecting a perfect finish. Just something to protect it and keep it looking fairly clean.

Anyone want an engine? Only 174,000 miles on it. But can share a video of it running nicely. Includes all ancillaries, ECU and EWS.

Steering Rack
The idea of putting a hydraulic steering rack in an electric car, when there are electric steering racks, just seems odd to me. But it may be what I end up doing. I tried a 1-series steering rack first but it was just too big in every dimension. So I thought I'd try a Mini steering rack, which looked a lot closer to what I needed. This will actually fit really nicely and I'm holding on to this option. But, the motor did protrude up into the middle of the engine bay where I will want to be putting batteries. Plus, the fewer parts I change the easier it is going to be to get this car through an MOT.

So I went back to the drawing board, or rather eBay, and bought an electric power steering pump from a Vauxhall Zafira. This seems to be the one everyone in the DIY EV community uses. We'll clean up the old rack and cooling loop and see if we can get it all hooked up.

Anyone want a 1-series steering rack?

Coupler
I'm at the stage of needing to connect my electric motor to my gearbox. I have had a plan for this from the start: design something in 3D, send it off to a company called Protolabs, and with their incredible CNC machinery they'll just knock it up for about £300 (based on a rough quote I got in the early days of the project). So, once I had the engine and gearbox out, and had separated the two, and extracted the flywheel, I finished up the design I had started around the motor splines. One thing gave me cause for concern though: the weight of that dual mass flywheel. That was going to put a lot of load on the motor bearings. Hmmm.

I cracked on and 3D printed a couple of test versions of my coupler before sending it off to Protolabs for a quote. They came back the next day with a quote of £350. I could live with that. Until I examined the quote more carefully and realised that it showed me their machines couldn't cut the splines for my motor more than about ten millimetres into the shaft. OK, so maybe it just needs manufacturing a different way. They did tell me they could 3D print metal. Sure enough, they could. For £1400.

Back to the drawing board again. While I was pondering, a chat with a fellow DIY EVer got me thinking about the quick and dirty option: find something that has the same spline pattern and weld that to one end of a tube, and the clutch centre to another. This would a) be very cheap and b) weigh a lot less, albeit with the loss of a clutch. But I won't be changing gear very often anyway...

Question was, what has the same spline pattern as a Mitsubishi Outlander electric motor. I stuck "19mm 17 spline" into Google and what comes up? A Fiesta clutch. Driving past my local garage a couple of days later (the one that has agreed to MOT my EV), I asked if I could have a dig around in their recycling bin for old clutches. Top of the pile was one marked 'FoMoCo' and sure enough, it had a 19mm bore and 17 splines. I got home and dropped it on the motor: perfect fit.

So, amongst the steel I have ordered (below) is a couple of pieces of thick walled tube. I've got a plan for how I might be able to do this at home. Obviously the ideal would be to get someone to make it up and balance it. But I have a few ideas. We shall see...

Fabricating
After a good chat with a steel stockholders nearby, I'm off to pick up a load of pieces tomorrow in return for a very large round of bacon sarnies. I'm getting a selection of box, tube, and plate that should be sufficient to make up the adaptor plate, mounts (possibly welded direct to the adaptor plate, and a frame for mounting the inverter and high voltage junction box. With a bit of luck we'll start putting that together on Friday and get a good chunk done over the weekend.

Wiring
With my daughter's help, I traced the routes from the ECU into the cabin and ran two shielded 7-way industrial cables. These now run across the ECU enclosure and out where the coil pack connections use to exit. This brings them out very close to where the 35-way connection on the inverter should sit.

One cable will carry the 5V signals from the throttle to the inverter. This is now terminated in the appropriate plug for the 1-series throttle pedal. The other routes around the driver's footwell and into the centre console where it will be connected to a forward and reverse switch that I've mounted in one of the blanking plates. It would all be soldered in but it turns out the switch I bought doesn't like heat very much. A replacement is on the way.

Lots more to tell but that will have to do for now.
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Re: Z3(00)

Post by bobby_come_lately »

Another week or so of big progress. Tomorrow (sore muscles permitting) I will test fit the motor and gearbox for the first time.

Adaptor Plate
The steel stockholders were great. They provided two 8mm thick steel plates, cut to size (400mm sq), 2m of 40mm box section, 2m of 20mm box section, a metre of 37mm i/d thick walled tube and a metre of 28mm i/d tube. Amazingly, I managed to squeeze all this into my Alfa GTV!

The plates are thicker than I was intending - it was a case of what they had. And I've had to crank my welder to the max to get a decent joint. But actually the measurements with the two plates and the box section in between turned out to be absolutely perfect to give the space I needed for the motor spindle.

Over the last week my daughter and I have measured and drilled the holes in each plate (marking them out with a transfer punch), bolted them up to the motor and gearbox respectively, welded on some captive nuts, then welded the two plates together with a square made from the box section in the middle. It took two hole saws and a lot of sharpening of bits but we got there in the end. As of today the whole assembly can be bolted together and it is ready to go into the car for test fitting.

There's still lots of work to do on the adaptor plate. It will need cutting down to save a bit of weight. Some of the holes need adjusting. A few more welds wouldn't go amiss. And then it needs painting. But first we need to make sure it all fits, and work out how the engine mounts will bolt up. Plan is to use some of the 40mm box cantilevered off the motor plate to bolt up to the existing engine mounts. The two circles of steel cut out from the centre of the plates are actually a perfect fit for the mounts. So those will be welded on underneath. It will all make sense when you see it.

Coupler
The steel tube was for the coupler to link the gearbox and the motor. Turns out I only needed the 37mm as both clutch centres will sit inside it if turned the right way around. The BMW clutch is a really nice tight fit so getting that square was fairly easy. The Fiesta clutch less so. It has funny little stepped splines that take a little balancing to get them square. And when I say 'balancing', I mean welding it, spinning it, cutting one of the welds off, hitting it with a big hammer, welding it again, until it looked pretty straight.

This just left me with the outside of the clutch centre to sort out. There's a few rough bits from where I cut it out with the angle grinder. I'd been looking for a local company to turn it down in a lathe. But then I got chatting to my neighbour from three doors down and it turns out he has three lathes in his basement workshop! It's with him now.

Before I dropped it round to him, we used it to make sure everything aligned properly before putting in the final welds on the adaptor plate. Sticking the box into gear I could rotate the prop end and watch the motor turn through the hole left by the clutch cylinder. Despite the rough way in which the coupler was put together it all seems to spin pretty smoothly. Hoorah.

CANbus
While I've been working on the hardware in the day time (when I can get away from work), I've been working on the software in the evenings.

So far, I have hacked together a little sketch for an Arduino Mega clone - one with loads of easily accessible i/o pins - that can read the CANbus data from the inverter and change its state or trigger actions based on what it sees. The first thing it does is switch between a series of states: Off/On/Charging/Run etc. Each of these states will require a different set of actions. e.g in run, I have two thermostatic switches coded that will turn on the cooling pumps for the motor and the inverter when they reach a defined temperature. These will be triggered by relays connected to the Arduino.

Next step is to start reading in the shunt data and then mount it all in the car so I can begin interacting with the ABS/ASC. Fortunately, all the devices seem to run at the same bus speed (500kbps).

I also need to knock up a mount for the Arduino, CANbus interface, and various sundries. I bought an old ECU/DME off a BMW forum and I plan to harvest the connector so that I can re-use the existing loom and connectors. The stuff I want to fit in won't go in the old case so I'll 3D print something that will slot into the old cradle.

Right, that's enough for tonight.
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Re: Z3(00)

Post by bobby_come_lately »

Right, refreshed after a week off and time for a bit of an update. Forgive me if some of this is either repeated or a bit noddy. I'm writing these updates in three different places and have decided just to copy and paste rather than writing it multiple times or doing lots of editing.

Test-fit
After the last update I did indeed get the motor and gearbox into the car where they remain now. It wasn't as hard as I expected and it all slotted in beautifully as you can see from the pics below. A bit of 2x4 was used to level it up over the x-frame, ready for engine mounts to tack it in place.

This obviously isn't the final fitting. Some holes need opening up to fit larger bolts, the welds need reinforcing (I may need a different welder - mine struggled with the 8mm steel), and it all needs trimming and painting. But this is good enough for us to begin the big game of Tetris that comes next: fitting all the components into the engine bay and making up brackets to hold them.

Fuel-line removal
Before we got a welder anywhere near the front end, we needed to clear out the fuel lines. I jacked the car up onto stands again and my daughter and I got very mucky draining (not very well it turns out) the fuel lines and removing them along with the filter and any other gubbins (what even is that black cylinder next to the fuel tank?) This creates some nice space for running the future high voltage lines from the packs I hope to install in place of the fuel tank.

We haven't removed the tank itself yet, just clamped the lines. But we did soak all the key nuts and bolts on the rear frame in penetrating oil in preparation. When it comes off, the whole lot is going to need a good clean up and a coat of paint at minimum. Diff mounts looked OK though on initial inspection, which I wasn't expecting.

Engine mounts
We need to finish the mounting of the motor with a couple of struts to tie in to the old mounts on the cross member. Originally, I had planned to just do single struts at a diagonal from the front of the adaptor plate. But once the motor was in it became clear these might be quite awkward and uneven. Instead, having test fitted the inverter my daughter and I settled on a U-shaped bracket coming around the engine from the front plate that would allow us to do a couple of simple struts down to the engine mounts from its corners. Picture might make more sense.

This has the advantage of forming the base for the mounting brackets for the inverter and the high voltage junction box and maybe some of the cooling pumps. We set the height of the U to be right for the base of the inverter, allowing relatively easy access to the various connections - 35-way connector for i/o, AC input for charging, AC output for the motor, and DC input from the batteries, plus cooling in and out.

My daughter measured up and we cut three lengths out of 40mm box, as well as two plates from a length of 3mm strip that may once have been the mounting bracket for an IKEA float shelf. I don't have a metal blade for my mitre saw yet so this was done slightly unevenly with the angle grinder. I think that might be a smart purchase. We tacked this all together but putting it up against the adaptor plate realised it was all a bit skewed. So instead we tacked the sides of the U to the adaptor plate as straight as we could and then welded the base piece across them. That worked a lot better.

Eventually the U will be bolted rather than welded on, but a few tacks will hold it for now while we measure everything else up.

The two circles I drilled out of the 8mm plate will form the base of the final two struts. Just need to mock up the struts themselves now to get the angles right. More cardboard engineering.

Coupler
Our neighbour, Doug, dropped the coupler back round having machined down the rough nubs left from my cutting the centre out from the BMW clutch. Looks nice now. I'll probably leave it with just a couple of welds for initial testing and then if it spins smoothly, put a seam on all the way around. If it isn't straight enough he has offered to help me align the two clutch centres as he has the kit to do it on his lathe.

Heater
I chanced across a 2kw, 220v engine heater on Wish (later found it even cheaper on eBay) that might be a good alternative to my plan of sticking an electric heater core into the BMW unit. Certainly a lot less work! Does mean more water sloshing around but it will do for now and it might also be a way of warming up the batteries on a cold day. Plumbing will be interesting. Will have to step down the 350+ volts from the battery to drive it though. At least if I am to run it within specifications. Expect the heater element would be fine with a bit more juice but doubt the integrated pump would be happy.

HV Junction Box
I've been working on finalising the HV junction box. This is where the contactors sit that switch the DC supply from the battery to the inverter (and vice versa for charging). I have probably laid this thing out about 20 times before I finally took the plunge and started drilling holes in the mounting plate. Still it was only after I had drilled three holes that I realised the polarity matters on the contactors (they're not just big switches) and so my planned arrangement wouldn't work. So, two holes in the wrong places. It's only cosmetic and I'm the only one who will see it but still annoying.

The other tricky bit about making up the junction box is connecting everything together. I figured I would have to make my own bus bars and so bought a load of 20mm x 2mm copper strip. Anyone with basic maths will realise this has slightly higher cross sectional area than the 35mm2 cables I'm using to hook everything up.

The only problem with this approach is that the contactors I bought are horizontally mounted while everything else is vertical, so my bus bars have to go through 90 degrees. I started by measuring out neat diagonals, scoring lines and trying to fold the bars along a couple of 45 degree lines to make a 90 degree bend, with a couple of other vertical/horizontal bends bringing it all back into a straight line. This worked OK but the finished result didn't look great and it took a long time.

So, on my third attempt I just stuck the bar in the vice and tried twisting it with a big pair of pliers. The result: a beautiful smooth curve with hardly any work. You live and learn.

Only seven more to make...

Engine: sold
The engine went off to Scotland this week to replace one with a terminal oil leak. Didn't get that much for it (£110) but after it being listed for nearly a month I just wanted it off the drive. The buyer left me with some of the ancillaries to sell so that will get a few more ££s in towards the project. Still have the exhaust to go as well. If nothing else the cat should be worth a bit.

Even at that low price, the car now only owes me less than £500 plus transport, so I can't really complain.

Next steps
While on holiday I updated my todo list for the project which spanned two pages before I got scared and stopped. But mostly focused on the big game of Tetris now: getting all the other components laid out in the engine bay and brackets/mounts made up for them all. I'd like to have that done this week so that I can pull it all out again for finishing and painting. While it's out we'll clean and paint the engine bay and probably give the front suspension a spruce up. Think one of the front springs is knacked so that will need replacing at the same time.

The big unknown remains batteries. I have an order in as part of a big group buy but it is not clear when or even if that will deliver. And I'm running out of time to get this car at least functional before my self-imposed deadline of the end of the month. So might just have to take the plunge next week and buy a small pack to get me going...
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