[itchyback]

I'm converting a 1969 Jaguar XJ6 to run with a Tesla P85 motor and 85kw battery pack. I want to drive it daily. I want it to look completely standard inside & out. I want to do a really classy/ professional job of the build with a similar comfort/ feel to a modern car. I have zero experience though so its a steep learning curve. photos below. Not my exact car but very similar.


My original plan was for a DC motor, powerglide and 30kw pack but I found a Tesla motor locally for little more than I would have spent on the DC motor so I grabbed it, same for the batteries. Its complicated the build somewhat but i'm enjoying (mostly) chewing on the problems and think its will be a classier, significantly more premium build when done.


I have the car, and have done a small amount of resto-modding. Removed the engine, welded up all the extra holes in the engine bay. It will get a coat of paint in time. I removed the front suspension and had it sandblasted and powder coated. I've upgraded the brakes and replaced every rubber bush with Nolathane and new ball joints too. I bought it thinking the paint was ok but on closer inspection it wasnt. I wish I hadnt spent as much on it, traps of old cars I guess. I added power windows and remote central locking. I'm trying to add AC which is as much of a challenge as anything. The car came with an aftermarket box under the glove box. I want the factory AC. I have nightmares about it fitting/ working/ breaking.

I had a range of rust to fix here and there, and there is a bit more to fix but if i fixed it all now i'd never get to the juicy bits. Leave the rest to the end.


I designed the battery boxes myself. When i pop the bonnet i want them to look clean and tidy. They had to be engineered to meet Australian standards, thankfully CAD has been useful in that regard.


The rear end will need to be redesigned entirely. The engineer didnt seem to worried about that so he has boosted my confidence. I'm thinking a trailing arm set up at this stage. Double wishbones could be tricky to fit around the motor.


As of today I'm in the process of bench testing the motor using the VCU. I also need to weld the battery mounting frame. Once those jobs are done, i'll eye off the motor mounting frame and invite the engineer to help design suspension. He has to sign it off at the end so working with him along the way makes my life easier. My quiet job is trying to devise a means for the VCU to drive the original guages. Im thinking of achieving this through an Arduino and stepper motors.

That'll do for now. more when i can find the photos i thought i had.

 

[itchyback]

As i mentioned earlier, i have rigged up a dodgy setup to test the motor. theyre basically jumper cable wires. which are fine for a few hundred amps at 12v, if i can just spin the motor without load for less than 20amps ish they should be fine. Thats seems pretty low, so feedback welcome.

Monday night i was successfully able to get the 12v section of the VCU working. Via laptop I can communicate with the motor, set various parametres like max power, low voltage limit, regen, and read CAN messages from it. It took some fiddling, my computer didnt have the correct drivers to use a piece of software needed but Michal was very helpful and tolerant of my ignorance. Wiring the plugs yourself is a pain! my motor didnt come with a wiring harness for some reason. I bought the plugs and elected to wire it myself for the experience and save $120. It took me hours, next time i'll buy it complete.

Frankly it was terrifying. I took on this project because i was interested in learning more about/ working with electricity. During the day i am a social worker and took to the project knowing nothing more than ambition and stupidity to help me. Having $10,000 sitting in front of my that could go up in smoke with one mistake. i was sweating.

As if the 12v stuff wasnt scary enough, Next is the High voltage side. We've already had a run in. I was tightening a bolt on a bus bar, mindlessly i rotated the spanner too far and it touched the terminal of the next battery over. Sparks blew out at my face and the spanner was briefly welded between the two modules. The bolt did get welded in place and i needed to drill and tap the hole again. Which was also terrifying drilling nearly $2000. The battery voltage reads fine and i got the bolt out. Some molten metal did melt something underneath the terminal, i cant tell what that is, I cant reach the coolant pipes to check that so for now, i'm hoping its nothing important.

In order to test the high voltage side and motor, I'm waiting on some parts. The VCU calls for three contactors. I have two high performance ones capable of handling more amps. I've ordered a basic one which is solely for the precharge and a resistor accordin to the instructions. Then i should be hours away from testing the motor.

 

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Buildmore; when i received your message i was actually looking at an XJ coupe to buy. I really wanted it, but it was very rusty and i just couldnt take such a big step back now i've done so much work on the sedan. :/

Brian; yes it was tempting to get the whole setup but one regulation here in order to get the car registered is that you cant widen the car more than two inches. Tesla is much wider than the jag unfortunately.

I've been grinding away at this but not as much as i would like. I've been wiring up the motor. That is damn scary i'm so afraid i'll connect something incorrectly. I am using an advantics VCU and that has bee difficult too. I expected the board to be sent back frmo them ready to spin the motor but i need to know how to do computer programming and work with CAN and i know neither. this wasnt made clear at the outset otherwise i may have chosen a different method. THe manual has limited information which doesnt help because everytime i take a step forward, i find out i need to get a piece of hardware or knowledge that takes me weeks if not longer to learn/ get. I could not recommend the advantics vcu to anyone unless you know how to computer program and have played with CAN before. Its not a skill that comes naturally too me so that complicates things. Michal has been working ok with me, i just wish he was more helpful given how little i know. If i ask something he doesnt want to answer, he just wont answer. for example i've asked he confirm the wiring of relays, recommend a program to work with CAN, asked if i can use arduino and CAN shield instead of arduino due, no response.

Last night i was working on it. I had made good progress but in the process blew up my contactors. I was testing the VCU's control of the contactors. I should have disconnected the HV wires but didnt. blew up both positive and negative contactors. bummer.

These few months has been an exercise in persistence and motivation. Balancing my time between physical results, like i've been welding a battery mounting frame, and the wiring stuff, has been helpful.

I have time off next week to keep building the battery frame. Will have to wait a few weeks to get some more contactors.

 

[itchyback]

Thanks Brian, you've put a lot of thought into your response, I appreciate your wisdom. I dont underestimate the challenges involved in creating the suspension from scratch however at this point i have benefit of ignorance and optimism .
I understand Damian used some form of trailing arm suspension on his BMW. as you said Porsche has used it for years and thats a good performance car so i know its possible and performance can be good. what level i can achieve remains to be seen.

A rudimentary design i had in mind was what i'd seen in offroad camper trailers. Fitting something OEM would be my preference because than someone smarter than myself has designed it. then it would also have torsion bars and proper bushings etc. I've vaguely looked around at existing examples but only as a proof of concept. once the motor is going, then rear suspension is the next phase of the project.

 

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Porsche has served up a variety of useful designs and with the sports orientation i'm leaning towards (60% cruise, 40% sports). Yes I did mean a stabilise bar. Thanks for the link to the autozone page, the specifics of 50-70 degree pivot angle are useful to have and i've kept the link in my document of suspension information. If you have any other useful links/ info/ documents I would really appreciate them.
Looking at the car, I can imagine some sort of multilink design, but it fitting and performing well dont necessarily go hand in hand. The semi trailing arm was easy to fit and function adequately. The original jag suspension uses the half shaft as a axially loaded member which I cant do with the tesla unit. Complicating things, the chassis design and motor size dont lend themselves to the introduction of an upper control arm. Its possible to have one now but it would be ridiculously short resulting in wild changes in camber. It may be possible to have one roughly above the axle but the chassis limits travel. I'm not clear on the rules yet but am working on the assumption I cant cut and move the chassis rails.if I can, I think I can widen the car width and change wheel offset and make something of adequate size and function.

I'm certain of finding a solution and confident I can find a way that results in reasonable performance.

 

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I stopped getting updates for some reason and regret not being up to date with the conversation. I had looked at McPherson Struts (the difference between them and Chapman struts is not immediately obvious, perhaps how they mount to the wheel hub?, i'll look into it further). Holding all the wiggliness of a 400kw car with a single control arm and strut seemed like a lot to ask so I had perhaps incorrectly, dismissed the idea early on for lack of understanding. There us heaps and heaps of space for struts and a lower control arm is easy to find space for so I should reconsider this option.

After our conversations so far, I had another look at the rear suspension today. The front upper control arm is about 20cm long, the lower, 30cm long, not as long as I thought. I had dismissed the idea double wishbone suspension would be possible in the rear. With some clever positioning, perhaps I could get something similarly long into the rear, I had expected it would need to be much longer to get reasonable wheel travel. The current rear lower control arm is about 45cm long and may need to be shortened, I imagine there is a sweet spot for the length of upper vs lower control arm. All that said, this train of thought has just landed me in the poo pile that is lining up u-joints and suspension pivots and I can feel a cold sweat coming on

As I said I had not put much thought to suspension design and now i'm suffering some errors as a result. For now I should put all options back on the table and educate myself for all options their strengths and weaknesses. Regrettably there is no perfect, easy and cheap option for my handling/ performance goals.

 

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Thanks Bry5on, I agree it is a shame to get rid of the original IRS. It appears difficult, but we have at our finger tips all of human knowledge in the internet. I am confident i can come up with something 95% what i want.

The transmission tunnel will be housing four modules, plus another two stacks of four on the front suspension. Plus four on the shelf above the IRS. Could probably fit a few more in the front but im trying to even out weight distribution and having four identical boxes minimises engineering design and certificate work/ costs. The spare tyre well is shrinking to fit the motor but is probably enough room left for a charger.

 

[itchyback]

If i'm ever in the US bry5on i'll look you up, would be great to shoot the breeze with a fellow jag lover.
I believe a strut tower would fit. The fuel tanks sit above the wheels so without them leave plenty of height. The bulge locates under the filler cap but there is still space forward of that.

Battery location has been a compromise. I'm trying to get it as low as possible. however the cells are quite long. one method I have designed is mounting them lengthwise which means they fit closer to the middle of the car. however fitting a stack in the transmission is taking up some dash and theyre just a little too long to make that work without altering th cabin appearance which i dont want to do.

Another option is Perpendicular, as Bry5on has done, leaves more engine bay room, better space for radiators if you need one. However one mounts almost entirely forward of the front axle, the other must be mounted 10cm higher than my original design to clear the chassis rails, as is visible in Bry5ons photos.

In the rear, i am losing most of the spare wheel well to fit the motor might check space again though. The 4 module stack is 34cm high (14'). i think i'll put a coolant motor or something behind the stack so i dont lose the space because of the sloped seat. There is very nearly enough room to mount two modules in the original fuel tank location. but mounting vertically and in such a position prone to collisions, i thought better of it.

 

[itchyback]

14months, i thought it was worse.
For all my spare time i now have a lovely new bathroom and renovated part of my house. Now thats done, i can get back to this.

i have the battery boxes made and their mounting frames. You can see two of the three locations mocked up with cardboard boxes. I'm pretty excited to have a frunk. Although in Australia, it would be called a froot.

I'm close to a solution for AC, i found a great company that lists all the individual parts with dimensions and that has been incredible to have when retrofitting something that never had AC!

Today i mocked the motor up into position, you can see i've made a rough jig to hold the wheel hubs in place while i build everything around them. The engineer is coming in 4 days to discuss the rear suspension, i have something i think will work but it really needs his eye to review it, he's forgotten more than i'll ever know about suspension design.

 

[itchyback]

Some good progress recently. I’ve found a rear suspension solution and worked towards it and got some more parts and solved some future brake problems.

Suspension
The engineer changed my rear suspension design to be harder to make but stronger. I was hoping for a sexy space frame rear setup but he encouraged me to look for OEM parts I could adapt to fit. I found a tutor to walk me through autocad to design the parts but stumbled across another solution. I found out the tesla I have parts for uses 120x5 pcd similar to my jaguar. For shits and giggles I put the rear tesla hubs in my hub jig and with the motor roughly in place found the upper and lower control arms actually fit really well. Using the complete Tesla rear hub, brakes and control arms will save a lot of time and money, both of which I can better spend elsewhere.
That makes a new problem that I either modify the rear brakes to be smaller (originally 355mm, Jag rotors are 280mm) or modify the front (which are 280mm). Seems stupid to downgrade brakes so I think I’ll put Tesla brakes on the front, 355mm rotors (which almost fit) and use an adapter to fit the tesla caliper. I think that will look good, I’m already using the Tesla brake booster so basically a whole system swap which is helpful for brake bias issues too. Briefly look at stand alone ABS (since the rears already have the hardware but quicly shelved the idea… well maybe in the future).

jig
This weekend I’ve made a ridiculous jig to align the wheel hubs and motor and copy the Tesla suspension mounting points to be able to translate them to the Jag. Its taken two weeks of brainstorming to make a workable design and another several hours to build. The suspension mounts need to be able to move inward to accommodate the smaller track width of the jag, as well as being able to move down because the jag is lower. The motor also needs to move up, I’ve raised it to improve clearance as directed by the engineer. I’m working on this build being really high quality so even though it’s a temporary jog, I paid a lot of attention to detail. I hope it pays off. I even added adjustable bolts so I can level the jig in two axis. The cars have also been levelled. Photos are of the completed ‘negative’ jig that fits within the chassis side suspension mounts. I need to add a ‘positive’ jig to locate it in the jag based on the control arms attached to the hubs in the hub jig.

@Bryson, Thanks for the tip, actually the lower radiator mount was dented when i got the car, i remade it from scratch with thicker steel. for batteries I’ll be using 16 tesla modules for a standard 400v Tesla battery pack. I’ve also got a Tesla charger I’ll hack with a Zero EV board. I got a bunch of coolant pumps, a radiator and condenser that may be too big but were free and a Astra power steering pump that I thought about swapping for electrically assisted steering but not convinced I want to. Would like to for efficiency but want to stay to keep road feel and I have the pump already… open to ideas.

 

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Thanks Bryson,
Jag wheel track is 146cm tesla is 168cm.
I'll take a photo of the brake booster. I've used the original jag brake pedal and linkage. The jag brake booster bolted to an aluminium box that housed the brake pedal pivot.
Your options are to use an adaptor plate in the range of 15mm to bolt them to each other or cut the pushrod shorter in the Tesla brake booster. I've opted for the latter because in either case you'll need to cut a relief in the inner wheel arch and i wanted to minimise any intrusion into that space. Some modest die grinder action on the aluminium box clears enough space for some nuts.

 

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I recall thinking about it but didn't. My photos suggest it may work so now I don't know what I was thinking.

 

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Thanks Blwnhr that's probably why i did it this way. I've checked and it clears the bonnet by 1cm or so.

 

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Hi Earz,
sure, i'll try to help. Michal is the guy who designed the board at advantics, he sold me the VCU

 

[itchyback]

Did you ever connect to the VCU with a computer? did you use Uniflash from texas instruments?

Yes and yes. I have no computer or electronics skills. I did it, it was very challenging.

Mtrehy
It's not finished yet. I'm trialling using the original tesla control arms and drive shafts and building a narrower subframe to mount it all. It sits too close to the ground currently. I want to double check I've set it up correctly and may move it around.