[DRIVING] Porsche Boxster 986 Tesla conversion [FINISHED]

[hotspoons]

it's only the boot floor that has been cut to accommodate the battery box.

I suspect that violates the "original or new and unmodified (direct from manufacturer)" requirement... surprised DVLA gave you a pass on that and it will be interesting to see what happens during your evaluation by a third party.

https://www.gov.uk/vehicle-registration ... d-vehicles

Well, thanks again for your interest and contribution.

[Boxster EV]

First update is that I’ve finally managed to get the UK authorities to recognise the car as an EV – You can read all about it here..








Second update – Power Steering:

At the beginning of this project, I set out with the intention to install the ubiquitous TRW electric power steering pump from a Vauxhall Zafira, but for one reason or another never bothered commissioning it. Instead, I just filled the system with fluid and closed the loop. I’ve been driving like that for nearly a year without an issue as the front end of the Boxster is light in relevant terms. However, I wasn’t enjoying using the car in tight parking situations and I’ve really noticed the winter roads get worse here in the UK - pot holes pulling the steering about (feeling magnified as system's not pressurised).

I decided to reinstate it but with a slightly different location for the pump. The standard high and low pressure lines run under the left hand side of the car and angle up into the engine bay from there. For the high-pressure side we made up a new braided line, connected to the OEM hard line via some AN fittings. These braided hoses and fittings claim to be good for 2000PSI – I’m not convinced but we’ll see.

The pump is mounted in an aluminium cradle (made by my fabricator friend), which allows it to be suspended from its rubber bushings (held down with three 10mm nuts). The cradle then sits on the battery box below it and bolts into the battery box next to it. Like everything in the engine bay, it’s designed so that the whole set-up can be detached from the battery box and suspended if the motor mount frame system (batteries, motor and HVJB) needs to be lowered from the car.

As ever the main 12v + feed is housed in 20mm conduit and clipped down using stainless rubber lined clips. These things are a very cost-effective solution for the HV lines too.

The steering is working as expected and I'm pleased the pump noise isn't as intrusive as feared. Just been for 20 minute drive around town and no leaks so far. Inspired by the Red Arrow project, it's hard to beat the TRW solution in bang for buck terms.

[Speedy]

Massive congrats on the V5 reclassification

[Boxster EV]

Massive congrats on the V5 reclassification

Thanks mate.

[canadasconvert]

Is the logic board you used from EVBMW still available? I didn't see it on their website. They are referring everyone to Open Source.
Since the motor is mounted backwards, how difficult was it to program the motor to run backwards or was it an actual swapping of electric wires?
Did you use an software from ZeroEVUK?

[Isaac96]

Is the logic board you used from EVBMW still available? I didn't see it on their website. They are referring everyone to Open Source.
Since the motor is mounted backwards, how difficult was it to program the motor to run backwards or was it an actual swapping of electric wires?
Did you use an software from ZeroEVUK?

EVBMW (Damien Maguire) has stopped directly selling Tesla boards, and Johannes Huebner has taken over the supply. https://openinverter.org/shop/index.php ... duct_id=64

AFAIK the only 'programming' is switching the forward and reverse input pins.

[Boxster EV]

Update time. A few weeks ago I was trying to get to the bottom why my CAN mapping wasn’t working properly. Through my own carelessness and bone-headed approach, I ended up with a catastrophic failure of the inverter. Johannes’s reminder to lower the occurlim value when experimenting is good advice if you don’t want to make a paperweight of your motor.

Damien kindly sent me another tesla LDU power stage to repair my broken inverter, but after a few days messing with it, I still couldn’t get it to work. I think the transistors are now sorted but there’s something wrong with the driver board. I fully intend to get to the bottom of the issue and will use it on my next project, but I’ve parked the repair for now and decided to put a ‘new’ drive unit in the car.

Clouds and silver linings

With the motor out of the car I could get access to all of those jobs on the list that started out as a temporary solution but became permanent, either because I forgot to revisit, or because I couldn’t get access to them. It was mainly low voltage wiring, replacing rusty brake lines and fitting stainless hardware to the frame system. Additionally this presented an opportunity to fit a Quaife torque biased differential.





I stripped down the replacement DU, cleaned the internals, checked the bearings, changed over the oil pump and VERY carefully sealed it back up again. Quite satisfying. I did a leak test too (pressurised the coolant entry to 3 bar to double check it held). I dread to think of the chaos caused by water getting into the gearbox housing / motor / inverter.



Scavenging the reverse drive oil pump from the old unit:

Removing the old DIFF from the ring gear. I had my fabricator friend do this as I didn’t have bearing puller or sufficient torque wrench to tighten the 16 bolts back up:

New drive unit inspected and cleaned:

Quaife ATB LSD installed:

Ready to go back in the car using the jack support made my fabricator friend. Simple but effective tool to be able to safely lift and manoeuvre the DU (on a regular hydraulic jack):

Adding the Dexron 6 fluid:

Early stages testing the diff but I’m finding it much smoother putting power down on loose surfaces. Just got to build-up the confidence to go further with some burnouts (damaging the old inverter is still fresh in my mind).

P.S: For those with a strong constitution; this is what happens when you drop a 130kg LDU on your fingers. Fortunately just bruising to hand and ego.

[Boxster EV]

Annual inspection passed yesterday. All good.

When I drove the car into the inspection bay I noticed that one of my headlights was aiming a little high (there were markings on the wall showing the acceptable range). I asked if I could quickly adjust it before he began - he said yes and 30 seconds later the aim was perfect (it's super easy to adjust on the Porsche). However the MOT guy was a bit cheeky and then failed the car for headlight aim! Anyway, ultimately he passed it and I'm good for another year.

[Boxster EV]

I’ve done a 1500 miles in the car over the past 8 weeks and it hasn’t missed a beat. I also haven’t felt the need to continually play with the drive unit parameters since spending a bit of time fine tuning and upgrading to the v4.97r Jon Volk modded firmware.

The only eventful thing that happened is rather oddly, my pre-charge resistors began to fail, so I took the opportunity to replace them and re-do some of my HVJB and engine bay wiring. Laziness previously got the better of me and the wiring wasn’t as clean as it should be. Therefore, I’ve added 6mm2 HV male/female connectors to the HVJB for the charger and DCDC, and trimmed down a lot of the HV wires exactly to size. No one likes chafing.

In other news, I’m about to fit a Tesla ibooster. Just waiting on an adapter plate and joiner to be fabricated and then it can go right in. The ibooster kit and how-to is available here: https://www.evcreate.nl/shop/

If one of you fellow Boxster owners on the forum feels the need to design an electric power steering set-up, I’d happily collaborate to help the project along. I love power steering, but decided I can’t live with the whine of the hydraulic pump.

The last little update is purely cosmetic – I’ve had some paintwork done on the car and managed to source a genuine Porsche aero kit. It’s meant to reduce lift on the front and rear and axles, but who knows – looks good though - Ha. Pictures to follow, although not overly interesting. Nice however not to be driving a car with junkyard paint.

[jon volk]

My Volvo pump sucks in terms of whine. I tried feeding it a variety of CAN messages that were documented for VSS and RPM to no avail. Im atually startign to look at inline shaft asssist motors as a possible alternative. I have a very quick rack ratio so I dont want to give that up.

[FJ3422]

My Volvo pump sucks in terms of whine. I tried feeding it a variety of CAN messages that were documented for VSS and RPM to no avail. Im atually startign to look at inline shaft asssist motors as a possible alternative. I have a very quick rack ratio so I dont want to give that up.

Z4 shaft drive motor could be an option. I'm about to order one for a testfit. Currently using a Z4 rack for a short ratio. Which rack do you currently use ? Also tried to fit an electric F20/F11 M-rack, but that does not clear the subframe around the torque sensor.

[jon volk]

My Volvo pump sucks in terms of whine. I tried feeding it a variety of CAN messages that were documented for VSS and RPM to no avail. Im atually startign to look at inline shaft asssist motors as a possible alternative. I have a very quick rack ratio so I dont want to give that up.

Z4 shaft drive motor could be an option. I'm about to order one for a testfit. Currently using a Z4 rack for a short ratio. Which rack do you currently use ? Also tried to fit an electric F20/F11 M-rack, but that does not clear the subframe around the torque sensor.

Im using the 2.7 lock to lock z3 rack.

[rjmcdermott81]

Man your HVJB wiring is super clean. Nicely done.

[Golf_mkIII_E]

What kind of fuse did you use for the LDU? I've got the performance LDU, and I'm a little afraid that the 630A fuse is not going to be enough. When blowing the fuse means that the LDU could die, that would be a shame.

[Boxster EV]

What kind of fuse did you use for the LDU? I've got the performance LDU, and I'm a little afraid that the 630A fuse is not going to be enough. When blowing the fuse means that the LDU could die, that would be a shame.

I previously ran a 400amp (continuous) fuse and pulled 1000 through it in short bursts with no issue. The Tesla fuse I’m using now is rated at 2000 amps peak.

[celeron55]

Always get a fuse which has a datasheet available. The datasheet will tell you how long you can pull different currents before it blows.

For example looking at the datasheet of some random Ferraz-Shawmut Amp-trap brand "Semiconductor protection fuse" (not an uncommon one in this application) I can see the 400A version will pass 1000A for more than 100 seconds, and 2000A for 1 second.

[canadasconvert]

I've got a question on the electric throttle in the Porsche Boxster. I am installing a Tesla LDU in the Boxster S and have temporarily mounted the Tesla motor and batteries in the car so it can roll for short distances on its own. I have the Tesla motor temporarily connected to a Ford throttle pedal to test speed and Forward/Reverse. I have contorted myself under the drivers side to look at the throttle positioner and wiring. I can see 6 wire coming out of the throttle potentiometer into a connector. The wire colours are white, grey, yellow, brown and green, violet. I have read in previous posts that these wires go into a loom in the trunk (boot). The Porsche Manual wiring diagrams show 6 wires in the boot that are GN/RD, GN/WT, GN/BK, GN/GR, GN/YE, RE/VI. Can I assume these are the same wires as those from the potentiometer? Is there another connector between the potentiometer and the boot? I cannot find 6 single colours wires together in any of the looms in the boot.

[canadasconvert]

Please disregard last post. I got it figured out.

[mtrehy]

Update time. A few weeks ago I was trying to get to the bottom why my CAN mapping wasn’t working properly. Through my own carelessness and bone-headed approach, I ended up with a catastrophic failure of the inverter. Johannes’s reminder to lower the occurlim value when experimenting is good advice if you don’t want to make a paperweight of your motor.

EDIT by johu: please quote selectively

Hi THere,

Great project - don't suppose you have any more pictures of your trolley jack / LDU support thing? I need to knock something up myself and rather than reinvent the wheel.......

Thanks

[Boxster EV]

Hi THere,

Great project - don't suppose you have any more pictures of your trolley jack / LDU support thing? I need to knock something up myself and rather than reinvent the wheel.......

Thanks

It’s very stable and means the LDU can be manoeuvred and raised into the car with relative ease, just by use of standard trolley Jack.

[mtrehy]

Thanks, much appreciated.

What's the point of the hole at the end? Bottom left corner of the picture above?

[Boxster EV]

Thanks, much appreciated.

What's the point of the hole at the end? Bottom left corner of the picture above?

Not required. It was there in case a separate bracket was needed for stability (it wasn’t).

[canadasconvert]

I've been following this build from the start and am trying to replicate it - so far so good. I have a couple of questions regarding the HV electrics.
1) Where did people put their manual disconnect? Should it be mounted close to the main contactor box or should it be accessible without having to pull the engine compartment cover? My main contactor box is mounted on top of the LDU. I have two battery packs (one between the firewall and motor and the other under the trunk).
2) Should I have second contactor box and individual contactors for the other HV components such as the charger, DC/DC converter, heater, etc.? All of these will be individual fused and have a manual switch in the cab.

[Boxster EV]

I've been following this build from the start and am trying to replicate it - so far so good. I have a couple of questions regarding the HV electrics.
1) Where did people put their manual disconnect? Should it be mounted close to the main contactor box or should it be accessible without having to pull the engine compartment cover? My main contactor box is mounted on top of the LDU. I have two battery packs (one between the firewall and motor and the other under the trunk).
2) Should I have second contactor box and individual contactors for the other HV components such as the charger, DC/DC converter, heater, etc.? All of these will be individual fused and have a manual switch in the cab.

I can’t speak about best practice, just what I’ve learned from others and read applicable to the Porsche

1) The HV disconnect switch is mounted in the middle of the pack. It’s physically located in the battery box under the boot floor inside another smaller HV box. This box has the battery fuse and another HV contactor (closes on ignition on / charge).

2) My charger and DCDC both have separate 15 amp HVDC fuses. Their + feed is connected to the battery side of the main contactor and the - side connected to the motor side of the negative contactor. I have a LV relay set-up and logic that’ll close the negative contactor during a ‘charge state’ but not power-up the VCU or other aux LV systems that aren’t required for charge (except water pump). Obviously the relay logic will also allow the negative contactor to close during ‘ignition on’ state.

There is another small HVJB in the front of the car that is housing the HV contactor for the PTC heater and charger stuff. It also has the 240VAC relay coil.

There is no HV continuity anywhere unless the car is on, or charging.

I need to update this thread with other developments on the car over the past six months. I’ll do a write-up this week.

As an aside, happy to help but you might want to start your own project thread and we can assist along the way with issues specific to your build. Just a thought.

[Boxster EV]

It’s been a while since I’ve updated this thread so here’s all the little projects that have taken shape over the past six months…

LV Wiring

I’ve rewired my ‘ignition on’ and ‘start’ power feed. Previously I was taking power and signals from the car’s original engine brain ‘cartronic system’ outputs (replicating the ICE set-up). This was fine however it meant that I had redundant wiring in the boot and from time to time the cartronic would do funky stuff when turning off the car, leaving the auxiliary systems running at random. ‘Ignition on’ and ‘start’ are now coming directly from the ignition/key (same as before but direct connection to the ‘start lock’ relay (boot relay panel #7) rather than through cartronic) – less complicated, more reliable. Simplicity rules.


For the 986/996 guys doing projects on here: take the bottom black connector from the cartronic brain and connect your ‘ignition on’ (startlock) relay to the brown wire with black tracer. That’ll given you an immediate ‘ignition on’ 12v connection from the key/ignition barrel. Use the thick yellow wire for the start signal. Other CAN based stuff that came from the cartronic is now being managed by my VCU.