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This one might be a little controversial to some but I'm posting it out here in case anyone else has an interest in taking something like this on. This swap is 99% reversible and I have everything to put it back together when these cars become 6-figures in 10 years . The only cutting done has been to remove the spare tire wheel well and that can easily be welded back in.
This is my first EV swap and I'm not a pro but a serious hobbiest.
Motor: Tesla Model S drive unit (motor, inverter, and single-speed gearbox) rated at 362 hp and 325 ft⋅lb or more Batteries: ElectricGT OX-Drive Power Color: Red, white, or maybe BMW Long Beach blue? more on that later...
Here is the car when I bought it. A good running automatic in good condition. I flew to FL and drove it straight back overnight without issue. I drove it as-is for ~6 months well I made my plan.
Last edited by rjmcdermott81; 11-30-21 at 10:18 PM.
This research is a bit dated (1 year old) but I used it to decide on how to control the Tesla Model S drive unit
I chose opensource route myself because of cost, customizability, and longterm flexibility, but each option seems to have it's merit.
Open Source (Ebay + EVBMW)
Control Method: EVBMW PCB
Total Price (Base Drive): $4,140*
Total Price (Base Drive + Quaife): $6,140*
Total Price (Performance Drive): $5,140*
Total Price (Performance Drive + Quaife): $7,140*
Includes:*
Damien Logic board: $739.20 shipped
Used Tesla drive unit (Base): $3,000 shipped
Used Tesla drive unit (Performance): $4,000 shipped e46 Pedal: $100
Low voltage wiring/miscellaneous: $200
Optional Quaife Differential: $2,000
Comments: This options requires you to do quite a bit of research on your own and support is provided by the Openinverter forum. It isn't plug and play out of the box. Prices estimated based on Ebay auctions September 2019.
If you get into a jam Damien offers paid support in a few forms - single email (€10), 30 minute support call (€60), or a full day (€450).
HSR Motors (057 Technologies)
Control Method: Outside controller talking to Tesla board
(1) High-voltage wires with connections for drive unit
(1) Instructions, pinouts, protocols for controller, etc
Comments::
EV Controls
Control Method: Outside controller talking to Tesla board
Total Price (Base Drive): $6,799*
Total Price (Base Drive + Quaife): $8,799*
Total Price (Performance Drive): $7,799*
Total Price (Performance Drive + Quaife): $9,799*
Includes:
The EV Controls T-1C Controller that communicates with the inverter over the CAN bus, and will allow you to do the following;
-Engage drive, neutral and reverse modes via the 7″ touchscreen,
-Adjust peak power output and regenerative braking power levels via the touchscreen,
-Display the following data on the 7″ touchscreen;
-Drive mode (D, N ,R)
-Traction pack voltage (HV)
-Inverter 12V supply voltage
-Accelerator position
-Stator current
-Actual power in kilowatts, positive or negative (regenerative braking)
-Max power limit
-Max regen power limit
-Five internal inverter temperature readings
-Vehicle speed (user adjustable scaling to account for wheel diameter)
-Current brake pedal and regen state
-Diagnostic data.
$3499 for everything listed above.
Comments: Requires pedal and low voltage wiring added to the price.
I don't see customizability to other gauges so I believe you need to be satisfied with the 7"" screen output.
Limited to S-85 and P-85 drive units
Stealth EV
Control Method: EVBMW PCB
Total Price (Base Drive): $7,800
Total Price (Base Drive + Quaife):
Total Price (Performance Drive):
Total Price (Performance Drive + Quaife):
Includes: Tesla Base Rear Drive Unit: Drive units removed from Tesla Model S and Model X vehicles with less than 25,000 Miles. Each drive unit houses an AC induction propulsion 3-Phase/4-Pole motor that can spin up to 16,000 RPM in large drive units and 18,000 RPM in low power and front drive units. The housing also includes the controller w/ Inverter and differential. Each drive unit comes with our own Stealth EV Controller Board replacement that allows for CANbus communication with any BMS, VCU, Hall Throttle, and switchgear. Wi-Fi access also comes standard for “in the field” or “on the fly” controller adjustments, no longer requiring USB connectivity or proprietary equipment.
Comments: Appears to be a drive unit with the EVBMW (Damien's) board installed. Requires pedal and low voltage wiring added to the price.
Zero EV
Control Method: Replacement PCB - based on EVBMW but further customized by Zero EV
Total Price (Base Drive): $12,159
Total Price (Base Drive + Quaife): $13,509
Total Price (Performance Drive): $17,086
Total Price (Performance Drive + Quaife): $18,436
Includes: Large Standard Drive Unit, Zero EV Control System, Open Diff, Drive Shaft Stumps, Display, Throttle, Gear Selector & Low Voltage Junction Box with Loom.
Options:
Performace Large Drive Unit 150BHP increase £3,995
Quaife ABT Limited Slip Diff (Highley recommended) £1095*when bought with drive unit kit.
Quaife Spool Locked Diff (for drif/ off road use only) £750*when bought with drive unit kit.
Drive Unit Coolant System Upgrade £795
Comments:
EV West Drop in Unit
Control Method: Outside controller talking to Tesla board
Total Price (Base Drive): $11,900
Total Price (Base Drive + Quaife):
Total Price (Performance Drive):
Total Price (Performance Drive + Quaife):
Includes: Includes: Tesla motor, inverter, gear box, dash display and control unit (EV Controls), throttle pedal, throttle pedal plug and pins, brake switch, brake switch plug and pins, encoder plug and pins, inverter plug and pins, axle clips, 2 axles, pre-charge relay, and pre-charge resistor.
Comments: Looks to be the EV Controls controller with a drive unit and all the trimmings to make it go out of the gate.
I don't see customizability to other gauges so I believe you need to be satisfied with the 7"" screen output.
Limited to S-85 and P-85 drive units
EV Shop EU
Control Method: EVBMW PCB
Total Price (Base Drive): $12,165
Total Price (Base Drive + Quaife):
Total Price (Performance Drive):
Total Price (Performance Drive + Quaife):
Includes: This kit includes the Tesla motor, inverter, gear box, power cables and drive shafts. And, Damian’s EVBMW inverter board.
Comments: Looks like they are packaging a used drive unit with Damian's inverter board installed.
EVTV.me
Control Method: Outside controller talking to Tesla board
Total Price (Base Drive):
Total Price (Base Drive + Quaife): $16,995
Total Price (Performance Drive):
Total Price (Performance Drive + Quaife):
Includes:
Tested and refurbished Drive Unit Motor/Inverter/Gearbox Assembly from salvaged Tesla Model S with Quaife ATB Differential installed.
GEVCU Controller with Tesla control software
Wiring harness
EVIC Tesla Display from Andromeda Interface
PKP2400 CAN Control Switch Panel for Tesla Drive Unit
This research is a bit dated (1 year old) but I used it to decide on how to control a Tesla LDU.
I chose opensource route myself because of cost, customizability, and longterm flexibility, but each option seems to have it's merit.
Open Source (Ebay + EVBMW)
Control Method: EVBMW PCB
Total Price (Base Drive): $4,140*
Total Price (Base Drive + Quaife): $6,140*
Total Price (Performance Drive): $5,140*
Total Price (Performance Drive + Quaife): $7,140*
Includes:*
Damien Logic board: $739.20 shipped
Used Tesla drive unit (Base): $3,000 shipped
Used Tesla drive unit (Performance): $4,000 shipped e46 Pedal: $100
Low voltage wiring/miscellaneous: $200
Optional Quaife Differential: $2,000
Comments: This options requires you to do quite a bit of research on your own and support is provided by the Openinverter forum. It isn't plug and play out of the box. Prices estimated based on Ebay auctions September 2019.
If you get into a jam Damien offers paid support in a few forms - single email (€10), 30 minute support call (€60), or a full day (€450).
HSR Motors (057 Technologies)
Control Method: Outside controller talking to Tesla board
(1) High-voltage wires with connections for drive unit
(1) Instructions, pinouts, protocols for controller, etc
Comments::
EV Controls
Control Method: Outside controller talking to Tesla board
Total Price (Base Drive): $6,799*
Total Price (Base Drive + Quaife): $8,799*
Total Price (Performance Drive): $7,799*
Total Price (Performance Drive + Quaife): $9,799*
Includes:
The EV Controls T-1C Controller that communicates with the inverter over the CAN bus, and will allow you to do the following;
-Engage drive, neutral and reverse modes via the 7″ touchscreen,
-Adjust peak power output and regenerative braking power levels via the touchscreen,
-Display the following data on the 7″ touchscreen;
-Drive mode (D, N ,R)
-Traction pack voltage (HV)
-Inverter 12V supply voltage
-Accelerator position
-Stator current
-Actual power in kilowatts, positive or negative (regenerative braking)
-Max power limit
-Max regen power limit
-Five internal inverter temperature readings
-Vehicle speed (user adjustable scaling to account for wheel diameter)
-Current brake pedal and regen state
-Diagnostic data.
$3499 for everything listed above.
Comments: Requires pedal and low voltage wiring added to the price.
I don't see customizability to other gauges so I believe you need to be satisfied with the 7"" screen output.
Limited to S-85 and P-85 drive units
Stealth EV
Control Method: EVBMW PCB
Total Price (Base Drive): $7,800
Total Price (Base Drive + Quaife):
Total Price (Performance Drive):
Total Price (Performance Drive + Quaife):
Includes: Tesla Base Rear Drive Unit: Drive units removed from Tesla Model S and Model X vehicles with less than 25,000 Miles. Each drive unit houses an AC induction propulsion 3-Phase/4-Pole motor that can spin up to 16,000 RPM in large drive units and 18,000 RPM in low power and front drive units. The housing also includes the controller w/ Inverter and differential. Each drive unit comes with our own Stealth EV Controller Board replacement that allows for CANbus communication with any BMS, VCU, Hall Throttle, and switchgear. Wi-Fi access also comes standard for “in the field” or “on the fly” controller adjustments, no longer requiring USB connectivity or proprietary equipment.
Comments: Appears to be a drive unit with the EVBMW (Damien's) board installed. Requires pedal and low voltage wiring added to the price.
Zero EV
Control Method: Replacement PCB - based on EVBMW but further customized by Zero EV
Total Price (Base Drive): $12,159
Total Price (Base Drive + Quaife): $13,509
Total Price (Performance Drive): $17,086
Total Price (Performance Drive + Quaife): $18,436
Includes: Large Standard Drive Unit, Zero EV Control System, Open Diff, Drive Shaft Stumps, Display, Throttle, Gear Selector & Low Voltage Junction Box with Loom.
Options:
Performace Large Drive Unit 150BHP increase £3,995
Quaife ABT Limited Slip Diff (Highley recommended) £1095*when bought with drive unit kit.
Quaife Spool Locked Diff (for drif/ off road use only) £750*when bought with drive unit kit.
Drive Unit Coolant System Upgrade £795
Comments:
EV West Drop in Unit
Control Method: Outside controller talking to Tesla board
Total Price (Base Drive): $11,900
Total Price (Base Drive + Quaife):
Total Price (Performance Drive):
Total Price (Performance Drive + Quaife):
Includes: Includes: Tesla motor, inverter, gear box, dash display and control unit (EV Controls), throttle pedal, throttle pedal plug and pins, brake switch, brake switch plug and pins, encoder plug and pins, inverter plug and pins, axle clips, 2 axles, pre-charge relay, and pre-charge resistor.
Comments: Looks to be the EV Controls controller with a drive unit and all the trimmings to make it go out of the gate.
I don't see customizability to other gauges so I believe you need to be satisfied with the 7"" screen output.
Limited to S-85 and P-85 drive units
EV Shop EU
Control Method: EVBMW PCB
Total Price (Base Drive): $12,165
Total Price (Base Drive + Quaife):
Total Price (Performance Drive):
Total Price (Performance Drive + Quaife):
Includes: This kit includes the Tesla motor, inverter, gear box, power cables and drive shafts. And, Damian’s EVBMW inverter board.
Comments: Looks like they are packaging a used drive unit with Damian's inverter board installed.
EVTV.me
Control Method: Outside controller talking to Tesla board
Total Price (Base Drive):
Total Price (Base Drive + Quaife): $16,995
Total Price (Performance Drive):
Total Price (Performance Drive + Quaife):
Includes:
Tested and refurbished Drive Unit Motor/Inverter/Gearbox Assembly from salvaged Tesla Model S with Quaife ATB Differential installed.
GEVCU Controller with Tesla control software
Wiring harness
EVIC Tesla Display from Andromeda Interface
PKP2400 CAN Control Switch Panel for Tesla Drive Unit
This research is a bit dated (1 year old) but I used it to decide on how to control the Tesla Model S drive unit.
I chose opensource route myself because of cost, customizability, and longterm flexibility, but each option seems to have it's merit.
Open Source (Ebay + EVBMW)
Control Method: EVBMW PCB
Total Price (Base Drive): $4,140*
Total Price (Base Drive + Quaife): $6,140*
Total Price (Performance Drive): $5,140*
Total Price (Performance Drive + Quaife): $7,140*
Includes:*
Damien Logic board: $739.20 shipped
Used Tesla drive unit (Base): $3,000 shipped
Used Tesla drive unit (Performance): $4,000 shipped e46 Pedal: $100
Low voltage wiring/miscellaneous: $200
Optional Quaife Differential: $2,000
Comments: This options requires you to do quite a bit of research on your own and support is provided by the Openinverter forum. It isn't plug and play out of the box. Prices estimated based on Ebay auctions September 2019.
If you get into a jam Damien offers paid support in a few forms - single email (€10), 30 minute support call (€60), or a full day (€450).
HSR Motors (057 Technologies)
Control Method: Outside controller talking to Tesla board
(1) High-voltage wires with connections for drive unit
(1) Instructions, pinouts, protocols for controller, etc
Comments::
EV Controls
Control Method: Outside controller talking to Tesla board
Total Price (Base Drive): $6,799*
Total Price (Base Drive + Quaife): $8,799*
Total Price (Performance Drive): $7,799*
Total Price (Performance Drive + Quaife): $9,799*
Includes:
The EV Controls T-1C Controller that communicates with the inverter over the CAN bus, and will allow you to do the following;
-Engage drive, neutral and reverse modes via the 7″ touchscreen,
-Adjust peak power output and regenerative braking power levels via the touchscreen,
-Display the following data on the 7″ touchscreen;
-Drive mode (D, N ,R)
-Traction pack voltage (HV)
-Inverter 12V supply voltage
-Accelerator position
-Stator current
-Actual power in kilowatts, positive or negative (regenerative braking)
-Max power limit
-Max regen power limit
-Five internal inverter temperature readings
-Vehicle speed (user adjustable scaling to account for wheel diameter)
-Current brake pedal and regen state
-Diagnostic data.
$3499 for everything listed above.
Comments: Requires pedal and low voltage wiring added to the price.
I don't see customizability to other gauges so I believe you need to be satisfied with the 7"" screen output.
Limited to S-85 and P-85 drive units
Stealth EV
Control Method: EVBMW PCB
Total Price (Base Drive): $7,800
Total Price (Base Drive + Quaife):
Total Price (Performance Drive):
Total Price (Performance Drive + Quaife):
Includes: Tesla Base Rear Drive Unit: Drive units removed from Tesla Model S and Model X vehicles with less than 25,000 Miles. Each drive unit houses an AC induction propulsion 3-Phase/4-Pole motor that can spin up to 16,000 RPM in large drive units and 18,000 RPM in low power and front drive units. The housing also includes the controller w/ Inverter and differential. Each drive unit comes with our own Stealth EV Controller Board replacement that allows for CANbus communication with any BMS, VCU, Hall Throttle, and switchgear. Wi-Fi access also comes standard for “in the field” or “on the fly” controller adjustments, no longer requiring USB connectivity or proprietary equipment.
Comments: Appears to be a drive unit with the EVBMW (Damien's) board installed. Requires pedal and low voltage wiring added to the price.
Zero EV
Control Method: Replacement PCB - based on EVBMW but further customized by Zero EV
Total Price (Base Drive): $12,159
Total Price (Base Drive + Quaife): $13,509
Total Price (Performance Drive): $17,086
Total Price (Performance Drive + Quaife): $18,436
Includes: Large Standard Drive Unit, Zero EV Control System, Open Diff, Drive Shaft Stumps, Display, Throttle, Gear Selector & Low Voltage Junction Box with Loom.
Options:
Performace Large Drive Unit 150BHP increase £3,995
Quaife ABT Limited Slip Diff (Highley recommended) £1095*when bought with drive unit kit.
Quaife Spool Locked Diff (for drif/ off road use only) £750*when bought with drive unit kit.
Drive Unit Coolant System Upgrade £795
Comments:
EV West Drop in Unit
Control Method: Outside controller talking to Tesla board
Total Price (Base Drive): $11,900
Total Price (Base Drive + Quaife):
Total Price (Performance Drive):
Total Price (Performance Drive + Quaife):
Includes: Includes: Tesla motor, inverter, gear box, dash display and control unit (EV Controls), throttle pedal, throttle pedal plug and pins, brake switch, brake switch plug and pins, encoder plug and pins, inverter plug and pins, axle clips, 2 axles, pre-charge relay, and pre-charge resistor.
Comments: Looks to be the EV Controls controller with a drive unit and all the trimmings to make it go out of the gate.
I don't see customizability to other gauges so I believe you need to be satisfied with the 7"" screen output.
Limited to S-85 and P-85 drive units
EV Shop EU
Control Method: EVBMW PCB
Total Price (Base Drive): $12,165
Total Price (Base Drive + Quaife):
Total Price (Performance Drive):
Total Price (Performance Drive + Quaife):
Includes: This kit includes the Tesla motor, inverter, gear box, power cables and drive shafts. And, Damian’s EVBMW inverter board.
Comments: Looks like they are packaging a used drive unit with Damian's inverter board installed.
EVTV.me
Control Method: Outside controller talking to Tesla board
Total Price (Base Drive):
Total Price (Base Drive + Quaife): $16,995
Total Price (Performance Drive):
Total Price (Performance Drive + Quaife):
Includes:
Tested and refurbished Drive Unit Motor/Inverter/Gearbox Assembly from salvaged Tesla Model S with Quaife ATB Differential installed.
GEVCU Controller with Tesla control software
Wiring harness
EVIC Tesla Display from Andromeda Interface
PKP2400 CAN Control Switch Panel for Tesla Drive Unit
Here's a shot from my 12-hour drive home. Drove it through the night with no issues other than - gas smell and no start unless you twist the key 5-10 times.
At this point, I started to plot and plan. I got the tesla drive unit measurements, jacked up the car, and started to measure. I'd never seen the underside of an RX-7 so at this point I was still going on blind faith that I could get something to work.
When you remove the gas tank and cut out the rear spare wheel well there is plenty of clearance in the back:
and plenty of width for the drive unit gearbox to fit if you cut the center of the subframe out:
This gave me enough confidence to buy a drive unit. Which I needed to do because without it, it would be impossible to figure out how to fit it in there. I bought it from a Tesla dismantler in CA, super cool guy and they delivered it freight right to my house. Here is unpacking day:
I found a spare rear subframe on ebay for $350 and I figured it might be wise to cut that one up and leave the one in the car intact for reference. Starting to eyeball up what needs to be done:
Behold! I found somebody online doing the same thing. He posted a couple pics on diyelectriccar.com and has the driveunit mounted so I know there is a path forward. He posted this picture on a forum and then disappeared... so no chance of getting help from him. In hindsight I can see that he dramatically modified the back of the subframe, cutting away the vertical supports completely and encroaching on the rear frame section of the car that goes across. My goal is to not modify the car itself so I won't make as many changes. He managed to get his drive unit farther forward with these modifications.
When I cut this subframe in half it's going to be in two pieces. I figured the first thing I needed to do was put it in a jig. I think there are a couple of ways to do this. Were I to do it again I think I would just weld pars directly to the subframe. I chose to drill holes in barstock, attach it at the suspension points, and then weld it to a frame I built. With the idea being to maintain the same suspension points.
After that I added a bar across that will eventually have the motormount attached to it. I went with 1.75 DOM steel tubing that is spec'd for roll cages. I figured if it's strong enough for that it's probably strong enough for this application. When I start cutting the center section out it will help provide support.
Now I'm starting to cut away the center section. Going a little bit at a time:
Even with that removed you can see there is a major issue. The motor and invertor are hitting the vertical supports for the suspension:
When I zoom in on the other guys subframe it is apparent that he's done some major major rework of this section. Nearly to the point that it looks like he's rebuilt the whole vertical piece:
You can also see that I decided moving a 300# object for test fits wasn't working. I created a scale mockup of the drive-unit. Much easier to move around
I also put my sweet jig on wheels because I am lazy
Now, here is where it's at after that grinding. You can see the axle inputs on the mockup. They are forward of the suspension pillars but ~2 inches behind the stock location for the RX-7 differential. If you look at the rubber pads on the bottom of the subframe, that is where the axles typically pass
Pulling it in to where it will live for the next few months. Once I start taking this thing apart it will only leave with that motor mounted.
Quick note - I got a quickjack over the holidays that runs off of 12v. It is rad. Not as good as having a lift obviously but I love it and I feel so much safer using it.
No mas wheel well. I expect this to be the only thing I cut on the vehicle. Truly, this would be easy to weld back in and convert everything back to ICE.
I did some final cutting on the rear subframe. At this point, I think my next step is to mock it up with the actual drive unit so I can add a cross support that will keep everything stable while I unbolt it from the jig. I originally planned to take this somewhere for final welding but...with the lockdown I'm gonna take a go at it.
Small progress. I have the motor mocked up at the right level and it allowed me to figure out how much more to cut out. I have one small bit I'm going to cut tomorrow and then I'll move on to fortifying the subframe so I can take it out of the jig.
I mocked it up with the tesla axles - these things are beefy. I didn't insert them all the way but I am concerned that it's sitting pretty far back. The only way to really tell will be to get the suspension on here and look at it.
Progress this weekend. I now have the two top lateral support bars completely welded in. I still need to clean up the welds more after I take it out of the jig but they are pretty much done.
Alright - now I feel like this thing will have the structural integrity it needs to pull it out of the jig. This is going to hurt ground clearance so I may come up with a better design when I get it all together. Last thing I'm going to work on before I do that is installing the front motor mount.
I took the advice and cranked up the welders so I've gotten some great looking welds and some crappy looking welds. Getting ready to pop it into the car and mount the suspension and motor to create the other motor mounts.
I decided this is a subframe so who cares what it looks like. I know if I started to do it then I would go down a rathole, so, if it looks like a 4 year old painted it. Well, a 4 year old did paint it.
I managed to get the motor up and the front motor mount bolted on.
I put the suspension and axles in to test fit everything. It looks like I have good clearance on the axles (these are just the rx7 axles in there for mockup purposes right now). The fit between the motor and the subframe is really close. I may have too clearance some material if I get contact. Not sure how much wiggle these motor mounts will allow.
Now that this is all looking good I am going to start working on the rear and side motor mounts.
Axle time! After quite a few "no you can't do that's" from machine shops I stumbled across a 4x4 forum and apparently shortening axles is a regular thing in that world. Dutchman in Utah specializes in this kind of work and it was incredibly painless and cheap.
Here are the two axles before (Tesla is the beefy long one)
Shipment back from Dutchman after just a week and a half and $175
And here are two of the beefy re-splined Tesla axles next to the Rx7 axle
11-30-21 | 10:15 PM
. The only cutting done has been to remove the spare tire wheel well and that can easily be welded back in.
