2006 Cayman S - EV conversion build thread

Hi Folks, Been awhile since I've posted because I haven't had a p-car in a few years. Thought I'd start this thread to document at least some of my newest project - converting a 2006 Porsche Cayman S to full electric. Sorry for the long post but figured I'd get this all down in one spot. Backstory Been wanting to do this since my wife and I test drove and bought a Tesla Model 3 Long Range Dual Motor car last year. Accelerates as fast as my old 996 turbo, but carries 5 people in comfort and silence. Truly impressive both from a performance as well as user experience standpoint. Based on living the EV lifestyle, I started re-evaluating what my priorities were in having a "fun" 2nd car. At the time I had a 2014 BMW M235i RWD which was tons of fun, but I didn't drive it very often, and not on very long distances. I started to realize that having a "sports" car with EV power and efficiency and not needing a long range is something that might be easily attainable. I started looking at numerous chassis/platforms to convert and options came up as the following that were reasonably inexpensive, good handling and could reasonably take the EV conversion without too much trouble: 996: plenty around, significantly depreciated, but no room in the chassis without cutting up the frame (may compromise structural integrity) Lotus Elise: Older pre-'07 can me found cheaper in the States and imported, but not as cheap as I'd like, but has been done. BMW E9X/E8X: plenty around, REALLY cheap and the Tesla Model 3 rear drive subframe is actually pretty close to the BMW subframe. But the clearancing issues may again affect integrity and I'd have to come up with an alternative for the rear swaybar as it's in the way. But this was highly considered and I nearly pulled the trigger on a 135i with a blown engine to convert to a Tesla-powered 1M clone. 987/986: Several people have already done this conversion using both a Tesla Model S Large and Small Drive Unit. The LDU is capable of 450hp and "drops in" with pre-fabbed subframes making it a bolt-in affair. The Car Given the ease and cost of the 986/987 chassis, as well as the fact that the motor and batteries would go where the motor/transmission is currently mounted in the chassis (and it's protected from impacts), I decided to go with the 987 Cayman. With all the bore-scoring going on in colder climates on the M97 engine (at least 3.4 and up), I knew it was only a matter of time before one came up for sale with scoring issues. I just picked up this car (yesterday!): 2006 Cayman S, tiptronic 67,000 kms - I'm in Toronto, Canada Sport seats, 19" wheels, rear wiper, not many other options Initial signs of scoring (smoking, tick, high oil consumption), but not yet confirmed with a borescope Mint condition, but history is somewhat unknown. I bought it from the person that imported it directly from Japan (it does have the steering wheel on the left) with all the original records and documentation, but in Japanese, including owners manual and service stamps! Other than the scoring symptoms, the car looks cosmetically like it's in great shape and drives like it's almost brand new (no shakes, rattles, issues of any kind). The Plan I'm thinking this may actually take a year to finish, given I'm planning to do all the work myself, picking up skills on the way (welding, 3D printing, CAN debugging and programming, and on and on). I plan on using the following components: Tesla Large Drive Unit from a Model S good for 450 hp with a custom-designed and built subframe. I won't get that much as it's limited by the battery, but hopefully it will be at least 400 Chevy Volt Gen 2 battery pack. Liquid cooled, designed for high discharge rates, lightweight, built-in cooling and cheap/readily available from junkyards Tesla V2 HV Charge Controller with open-source controller board Open-source Tesla LDU inverter and software DC-DC converter TBD Battery Management System (BMS) TBD Existing Cayman cooling system with inline pump to cool batteries and motor Aftermarket AC and heating TBD Obviously there's alot more to work out, but it's started. First order of business is to do a bore-scope on the engine to confirm that's what it is. For convenience, I'm going in from the spark plug holes initially to see if I can see anything obvious. Next is to drop the engine and tranny (engine is spoken for, but tranny is for sale, if anyone is interested). I might start a youtube channel/insta, etc to document each step (starting with the bore-scope) as alot of people have been asking me where they can follow my progress. I'll see how that part goes. Wish me luck. All comments, questions and feedback is welcome!

I still need to read all this but it sounds interesting…. It’s been done. I’m curious on the weight. Good luck! Should be fun to watch the build

IMHO, this is sacrilege

Really cool project. Wish you luck. I just rebuilt the engine in my Cayman (bought it with bore scoring) and I've considered a project like this if the engine ever goes again.

Totally get this. I'm sure in 10-15 years this car with a gas engine will be really sought after, especially with the induction and exhaust sounds. However, (and this might cause even more controversy) it is a tiptronic which personally feels waaaaay worse than a proper manual gearbox. The difference with an electric motor is 400 hp at instant torque which makes up for fun in so many other ways....

Certainly prefer I light car with an ICE, but I get the appeal of instant torque in a chassis that handles well. I much prefer the sound of the flat 6 so EVs are not for me. But I am sure I would enjoy it if I had a go in an EV Cayman .

I think I'll be following this - and as you do the YouTube videos - please embed them in posts in this thread. I think they'll be quite popular.. Great thread!

I'll give this a follow. Very curious on the outcome.

Would love to see this. Gotta do that YouTube channel.

Gonna be interesting! I applaud you for the guts to put this together.

Sorry for the delay. Things have been busy trying to clear space and wait for the weather to get nice to start on the project. First thing was to confirm whether the car I bought actually did have bore scoring. It'd be a shame to pull it apart if the engine wasn't bad.... This was cylinder #6 (driver's side, rear most cylinder) taken through the spark plug hole. I think it's safe to say we've got some scoring..... So on to prepare for engine removal. Hopefully over the next few weeks I'll be building some wheel cribs to lift the car up, get the AC refrigerant removed, drain all fluids, and then drop the engine and tranny! I've been keeping busy with another mod. Check out my other thread which I'll update here shortly.....

I started converting my 2006 987 Boxster S in 2021 during the pandemic. Also a tiptronic, so I figure I'm saving this car and Porsche 's namesake. The 3.2L has 85K miles and runs strong. I can send you a video I took just before removal if anyone is interested. I have to admit that I'll miss the sound a bit, but not the overall tiptronic experience. I much preferred my 2005 Boxster S with 6 spd manual. But this vehicle was purpose bought for a conversion. Having 400+ hp will help ease the loss of the intake breathing behind your head. Specs: Tesla performance LDU (2015) Quaife Limited Slip diff (Zero EV) Likely a Chevy Bolt battery (being sized for fitment) F1moto sub-frame . Bolted right in! Very happy with the build quality. Tesla brake vacuum booster Tesla water heater A/C undecided Polykup VCU (ended up bringing it to them to finish up the conversion...don't have the time and want to drive it) Looking forward to following your progress.

This is just a teaser right? You are going to tell us the whole story... Might I suggest that first you visit New Member Introductions and introduce yourself and a brief introduction to your EV Boxster with a few photos, THEN come back and create a new thread here on what you did, how you did it, planning, machine work, etc. and then who finished it up. It sounds like it will make a fascinating story!

Slow progress, but finally started preparing for the engine/tranny drop. Following the guide on Pelican Parts for the 986 but a few things different that I'll try to capture as I go. I have a lift table and an engine hoist that I'll use. So far, I've followed the prep and removed/disconnected everything in the engine compartment and rear trunk. Put the car up on these wheel cribs that I made and now about to start removing/disconnecting/draining stuff from underneath. I'll also remove the rear bumper to provide better access. Wish me luck!

I'm curious about the Volt battery pack. As the Volt is a plug -in hybrid, I wouldn't think it could provide enough range for more than around-town errands. Am I misreading something here?

The Volt and other similar hybrids that are in the 350-400V range have the unique ability to discharge (C-rate) reasonably quickly. This combined with the higher voltage means it will be able to use more of the 450hp motor for short periods of time ie. accelerating. I don't plan on using the car on the track, just having short under 50 kms drives. I'm told others that have done this with similar setups have gotten almost double that with the Volt battery , so I'm not worried about it. There's still room to add more batteries if needed, and they are cheap compared to Tesla battery packs.

Are you dropping the engine with the car on those wheel cribs? The manual has a warning about having weight on the wheels when the cross beam under the engine is removed. The suspension isn't properly supported without that crossbeam so you could bend things.

Also, just eyeballing the picture, that doesn't look high enough to get the engine out. The bumper isn't much of an issue, it's actually the suspension components hitting the intake manifolds. It has to be a good bit higher than you would think to get it out. If you pull the intakes off, it'll buy you a lot of space.

Really appreciate the feedback. I'll have a look at the weight on the wheels issue, but the cribs have a middle piece so I can just move them over to the jack points and use them with jackstands when I need to. For the height, I don't think it'll be enough as-is either. That's why I have the engine hoist. I'll be getting all of the prep done (disconnecting, draining, etc) in this state, lower the engine using the lift table, and then raising the rear of the car from the back bumper support so that the engine can clear. Not straight forward, but you gotta do what you gotta do when you don't have a lift....

With those goals, the Volt battery pack seems like a good choice. But I can't see myself going to this effort and expense for 50, or even 100km range (30-60 miles). Around here that's just barely enough to run daily errands. I'd want to build a car that I could use as a normal car - say a bare minimum of 320km (200 mi). I'd want to be able to do a fun day trip and back home on a single charge. But I'll still follow your thread, as everything except the battery is applicable to what I'd consider doing myself.

I think the boost brothers on YouTube pulled the engine out similarly. They dropped it and lifted the car with a hoist. Looked quite precarious. Be careful.

Little behind you in the process, been researching feverishly over the past few weeks. I’ll be paying close attention, YouTube would be great to watch and very informative for the viewers.

Sorry for the delay. Been a little busy removing stuff.... Exhaust out Transmission dropped - Anyone need one? Mint condition, only 67k kms. Cheap! So much room without the tranny to get at the engine now.... Next step - engine drop.... Notice the replacement that will be going in on the cart. I did end up having to raise the rear up a few more notches on the jackstands. For reference, the lift cart top surface is about 13" high in it's lowest position. Even with the car this high, I still had to turn the engine/cart 90 degrees and slide it out sideways as it's too wide to fit between the suspension upgrights. Test fitting of the Tesla motor subframe. You can see how high I had the jackstands which were in the same position previously to remove the engine. Sorry I don't have videos on youtube. Still thinking about this but it may be awhile. For those of you considering an engine or transmission drop, it's actually not too bad. For documentation purposes, here are the "special" tools I used aside from standard sockets and screwdrivers, pliers, etc: Various length wobble extensions for the socket set. 12-pt triple-square 10mm bit socket for one of the transmission-to-engine bolts Various size allen bit sockets Extension handle for the socket set to give extra loosening leverage Hydraulic lift table. Mine's 500 lb capacity and was critical for lowering the tranny and engine as a one-person job. 2x4 wheel cribs as you see here. If I did it again, I'd put the front on jackstands sitting on the wheel cribs as well. As you see, the car is tilted a bit (higher in the back than the front. Made it a bit difficult to slide the transmission off the input shaft of the engine. Not impossible, just a little finnicky. What's next? I was going to try spinning the motor with a 60V power supply to ensure the controller and motor works, but realized after doing research that Tesla Model S motors (also in the X), tend to have a design flaw where the coolant seal tends to fail. After checking (simple 5 min affair), mine was suspect enough that I've now split the motor and am in the process of replacing 2 seals and a bearing just as a precaution, along with some other preventative modifications to the case. So I'm stuck waiting for parts to ship to me from China and the Ukraine of all places. I'll upload some more pics soon. I do have to say that so far, it's been relatively easy to get to this point from a typical mechanical standpoint. No seized or broken bolts, no accidents, nothing bent or snapped, etc. And given the Tesla motor is 300 lbs, the lift table is also really handy for moving it around and raising it up to almost a working height level to work on. Highly recommended.

Subscribed, I’ll make the popcorn. where are you going to put the batteries? Being mid engine I can’t see a good car balance with batteries up front.

Sorry for the delayed response. The project has been slowly progressing. I'll add a few pics soon. I was able to connect a bench power supply to the motor and the "gas" pedal from the car and it spins! So now, onto the test-fitting. So far, I've fitted the motor in the subframe in the car and now am proceeding to remove the fuel tank in the front to free up the space. 2 of the 3 battery banks will fit in the subframe directly in front of the motor where the original engine sat. The 3rd battery bank which is 2/3 the size of the other two, will fit in a steel box underneath the existing trunk accessible from the trunk where the exhaust previously was. So the trunk will remain usable as will the frunk. I've ordered driveshafts which will be coming in soon to complete the test fitting and I'll then be mocking up the battery boxes to have them fabricated. Stay tuned!

Any update?

With an EV cayman coming soon, not sure this is worth it, other than from a cool project perspective. Not a dig in any way, I love these projects because you learn so much and you can say you did that. Good luck.

Hey - I’m converting an 06’ boxster . Using a model x rdu and an 85kw Tesla battery pack (16 model s modules). Reach out if you need any info - Also - for the model s motor, they have a coolant leak issue that can ruin your inverter. Qc charge out of Oceanside California just released a coolant delete for the model s motor. There’s also an lsd by quaife (via fellten) - just had an lsd installed in mine -

Well, it's been two years. I'll post some pics in a bit. Needless to say it's been awhile. Alot of work has been done to the car, mainly in my spare time which is why the progress has been so slow. But where I am at is: the car is driving and charging! DC-DC is also running, as-is electric power steering (copy of Porsche motorsport unit/setup), electric brake booster , cooling system and BMS. Temps are keeping cool for the 10 min runs that I've tested for. I've installed a PTC heater and Tesla Gen 2 AC compressor but haven't charged it yet and neither is wired into the car. I've also got an arduino setup to provide the CAN signals to run it. Where I'm at now is now starting to figure out how to tell the car not to freak out because there is no longer a motor or transmission. Even the climate control is not commanding heat or cooling. ABS, PSM, PASM and airbags are all in error state. I think the only thing working is the speedometer. So when I drive it now, all the dash lights are on. I'll post pics but if anyone has any comments, questions or suggestions on approach to address, please post them up. I'll most likely connect into the car's CAN system to listen and send commands to mimic various engine and transmission signals, but it may be as simple as terminating the CAN wires where I removed the DME ..... By the way, although not professionally measured, the car is FAST, quite a bit faster than the original motor/setup. Thanks in advance!