# BMW Z3 Coupé, Siemens, DMOC conversion



## PeterS (Jul 30, 2013)

Enough story and time for the project at hand!

The plan is to convert a 1998 BMW Z3 2,8l coupé to 100% electric!

*Motor:* Siemens 1PV5135-4WS14. *got it*
*Controller:* Azure Dynamics DMOC645 *got it* along with the GEVCU from EVTV *on its way*
*High voltage chargers:* 2 pieces of Brusa NLG513 3,3kW each for a total of 6,6kW charging power *got it*.
*High voltage battery:* Complete pack from a wrecked Nissan Leaf 24kWh.
*Low voltage battery:* 4S LiFePO4 250Ah with BMS used during charging.
*Low voltage charger:* Not known yet, but probably around 6-800W.
*Vacuum pump:* Not known yet, might be from a Volvo V50.
*Power steering:* The car has hydraulic power steering, but I might fit an electric steering column, not sure yet.
*Heater:* 1500W of electric heaters, boiling a couple of liters of water and feeding the original heat pack of the car.
*AC:* The car is equipped with a working AC driven by belt of the ICE. Might use that if I can connect it to the Siemens motor, if not, I will skip the AC, or buy an electrical powered unit.


The BMW is a former track day car with only 138000km on it. It´s fitted with a Wiechers roll cage, HR coilovers and E36 M3 brakes in the front. I didn´t bother taking any pictures of it before I started to rip into it, but found one on Facebook from a former owner.
It has been repainted and as a collegue said "It sticks out like a hole of piss in the snow!" 

The plan is to use 2 JLD404 for measuring current and Ah of both the high voltage and low voltage battery. I will probably not get the original rev and speed gauge going again, so I will replace them with after market ones from VDO. Seems fitting for a german car.


----------



## PeterS (Jul 30, 2013)

This sunday I got most of the ICE related parts out.
Had to remove much of the interior as well, since the roll cage was very nice installed with carpeting, panels cut out and so on...

Batterys will go in the square compartment behind the seats, and also at the most rear where the original battery and exhaust were located.
They will not all fit here I think, and to even out the weight some, I will put the 12V 250A battery in the front, and also the rest of the traction pack.

To get the fuel tank down, the entire rear subframe had to come down. No big deal as I plan to change the bushings anyway...


----------



## adriftatsea (Oct 5, 2015)

I dig this!

Are you using the OEM transmission (ZF 5 speed, right?)? Do you have any expectations on power versus the 2.8L (or really the 400whp turbo setup)? I have a similar vehicle past, a caged e46m3, and a pile of ev parts ... but I can't convince myself it will be fast enough by stuffing it full of 'ford transit' parts:/. I look forward to how this turns out.

Also sweet e-bike and shopspace.


----------



## PeterS (Jul 30, 2013)

Yeah, I will be using the original ZF 5 speed. Probably only in second gear. That will give me 300Nm up to about 50km/h, and by reving 8k or so, the car will do 140km/h, given that the torque at that rpm still can push the car forward. Not sure how this works really.

Seeing as the original ICE has 142kW and 280Nm, and the Siemens 120kW and 300Nm, I expect similar or better performance up to 50km/h, and maybe a bit slower up to 100km/h. 
Time will tell...


----------



## Moltenmetal (Mar 20, 2014)

Cool project- best of luck! Keep us posted, so we can enjoy vicariously!


----------



## PeterS (Jul 30, 2013)

So the next step is to mate the gearbox and the motor. There will be no flywheel and no clutch... Partly because of weight saving, and partly because of "KISS" - Keep It Simple Stupid!
And also, the motor has normal deep groove ball bearings, not really made for the axial load that the clutch pressure plate would put on it. So if I was going to use a flywheel, I would have to build some sort of bearing holder or replace the motor bearings... Naaaw, too much work, and hopefully no need for quick shifts...

Anyway, I need to make an adapter plate between the motor and gearbox, so I have made a axle that fits snuggly on the "guide tube" for the clutch bearing. I don´t want to use the input shaft on the gearbox for determening the center, because this can move a couple of millimeter X and Y.

With the axle fit on the gearbox, I will mill a 30mm hole in a piece of aluminium and place this on the axle and then use transfer punches to mark the mounting holes.

Before I can order some aluminium, I need to sort the adapter between the motor axle and the gear box axle. I have two adapters with the correct spline, and the plan is to just make a piece on the lathe to bolt them together. However, the adapter for the gearbox is really sloppy, and I think I need to make something that guides the gear box axle better. Haven´t really had time to look in to the matter much...

As I will be using the mill very much in this project, I needed to make sure that it was at the right angles in X and Y. And boy was this necessary! The table can be rotated around the Z axis, and it was off by 1,9mm on a strech of 160mm! No wonder parts I have made in the past haven´t come out a 100%!


----------



## PeterS (Jul 30, 2013)

Nothing really exciting happening at the moment...

Got some fuses in the mail today, should do the job just fine.

I´m planning to use them both, having a fuse between each of the (probably) three battery boxes.


----------



## Moltenmetal (Mar 20, 2014)

Fascinating to see your thought process fir how to attack the making if the mounting plate. I wish you well with it!

Unless I misunderstand, you will be able to use transfer punches to mark a few of the mounting bolt hole locations, but not all- the ones that seem to be blind threaded holes will need to be marked by some other means. And alignment is usually done with dowel pins rather than bolts, is it not?

I'm puzzled by the expected movement of the transmission input shaft you mention. Is this shaft not usually carried by a bearing mounted in the end of the IC engine crankshaft? My motor hub from CanEV came with a bearing for that purpose.


----------



## PeterS (Jul 30, 2013)

You are right about the alignment, the bolts themselfs will not do a good enough job.

With the ICE, there are one 6mm dowel pin and two tube-like steerings for the alignment. I must try to replicate these some how. 
I´m currently making a couple of test adapters using a wood fibre board from Ikea 

You are also right about the pilot bearing for the gear box axle. I will not have a bearing, as I will drive clutchless and the axle will always spin at the same speed as the motor. I will however have a support for the end of the axle to keep movement down.

I took apart the ICE and original gearbox to source the clutch plate, this clutch center had much tigher tolerences and was a bit longer than the previous spline adapter i bought, so I will work on a solution to use that one instead...


----------



## PeterS (Jul 30, 2013)

Got some more stuff in the mail today, the internet is great! 

Got three ECPC404 (same as the JLD404, at least looks the same, functions the same and tastes the same, but at almost half the price) and a couple of shunts.

I will be using two of the meters in the car to monitor the traction and 12V battery, using the built in relays to cut off if the voltage is too high or low.

The third meter I will use as backup, and also to bottom balance the cells...


Also got two contactors, Tyco Kilovac EV200, rated at 500A continuous. I will use one as the main contactor with a precharge controlled by the GEVCU, and one will sit mid-pack connected to the emergency stop buttom and crash sensor...


----------



## PeterS (Jul 30, 2013)

More stuff! The mailman knows his way to my mailbox by now 

Got hold of a second hand, never used GEVCU from the states at a fair price...

Now I actually have all the pieces I need to spin the motor. Not sure if I will hook everything up outside the car just to see if everything works, thinking that I kind of need to.
Got a Kvaser Leaf Light from Kvaser themselfes (they are a swedish company and saw this as a cool project and wanted to help).
I really should flash the DMOC and see if everything spins, but as it is now, I can´t seem to even get time to go and work on the car.


----------



## PeterS (Jul 30, 2013)

Got some time in the workshop today...

First of all I got the damn roll cage out! Had to take apart the entire inside of the car more or less. This will be sold to a friend with a track-day Z3...

Then I got the old clutch center up in the lathe. Put it in the 4-jaw and indicated it to around 1/100mm. Ground myself a rounded tool to get full access to the entire length. Turns out it was some sort of cast iron.
The plan is to make a hub to go over the outside, with maybe 1/10mm in negative clearence so I can heat it up and press fit it on.
Seeing as the spline hub was cast iron, my first plan of putting a small bead with the TIG-welder went down the drain.
I will see about getting some braze-rod and braze it in place instead. Hopefully this will stand up to the torque.

I also turned a centering device on the lathe, that will center the gearbox axle to the motor axle.
The motor had a M8 thread and a 60 degree chamfer in the center, so the fit should be dead on!


----------



## PeterS (Jul 30, 2013)

So this thread has more or less died out unfortunately...

But the building has proceeded, and last sunday I got the car down from the lift and did the first test run!

Yesterday I hooked up the watercooling to the DMOC and Siemens motor, and did som other stuff, not related to the GEVCU or DMOC.

Then a friend came by, and I wanted to show him the wheels spin, even if the car was up on the lift.

I have the throttle mapping so that 0-5% is coast, 5-25% is regen, 25-35% is coast, and 35-100% is forward, basically the standard settings that the GEVCU comes with.

But then I noticed the strangest thing, after reving up, and regen, after I let the throttle go fully, the motor started turning backwards at about 700-800rpm, for 2-4 seconds before coming to a stop.

This might be a fun thing at the stop signs  Thinking the car is going to roll to a gentle stop, but then it starts going backwards into the car behind...

First I thought that the car beeing up in the air had something to do with it, wheels turning very easy, and no load essentially.
And regen is requesting a negative torque from the controller, thus maybe making the motor go backwards. But then again, this happens in coast...


I´m going to do further testing today, but if someone has any ideas I am grateful...


----------



## PeterS (Jul 30, 2013)

It does have something to do with regen, thats for sure.

When I set regen to 0 it does not happen.

It seems like it would have something to do with the throttle mapping, but my set values seems fine.

I didn´t get much done today in the garage, almost started to cry because all of the bugs in the GEVCU.
Took me something like 20 tries before the GEVCU saved my settings on MRELAY=7, instead of MRELAY=5.

In the terminal, typing "H", it said that the MRELAY was indeed 7, but after a reboot everything was back to factory settings again.

Do I have bad hardware, "Made on a monday" like we say here in Sweden, or are the GEVCUs simply not better than this?

I cant really use the car as a daily driver if I need to complete a session of troubleshooting with the laptop each morning. 
I´m having problems getting up on time for work anyway...


----------



## wallywalker (May 18, 2019)

Sorry to bring this thread back to life after so many years - But this is the exact car I hope to convert one day.


OP have you had any success with getting the car on the road?


Do you have any updates about where you put the batteries, and about wiring into any of the the car's dashboard instrumentation and displays?


----------

