[WIP] 1981 Porsche 928 with 2015 Nissan Leaf [FINISHED]

[bapshago]

My daughter and I decided to convert an electric car in July of 2025. We opted to use the Nissan Leaf Stack and Nissan Leaf Battery with a Zombieverter VCU in an attempt to keep cost low. The primary goal is to gain experience and knowledge in the conversion process. A friend had an old 928 with no hope of restoration and he was willing to donate it to the project. Since the 928 uses a transaxle and rear CV joints we choose to remove the entire engine, torque tube and transmission and mount the Nissan leaf motor and gear box in the rear of the vehicle. We took inspiration from a few folks on you tube who had gone a similar route with Tesla and MG electric motors. To minimize any structure changes to the car we decided we would mount the motor and gear box backwards, planning to swap the phases and resolver wires.

[bapshago]

The first order of business was to pick up the Porsche from my friend’s house, 10 hours away, and take it back to the shop in Ohio. We rented a uhaul trailer and borrowed my nephews truck and the adventure began.

[bapshago]

Once the car was in the shop we could remove the fuel system, transmissions, torque tube, bell housing and engine. The harbor freight engine hoist we purchased was not long enough to remove the 928 8 cylinder engine, so we had to rent one.

[bapshago]

We purchased a wrecked 2015 Nissan leaf from CoPart and began to remove anything we thought we might need. Removing the entire front clip was the easiest way to remove the stack.

Then we decided to buy a second 2015 leaf via copart. The idea was to have spare parts and to be able to keep the bench test setup while we installed the other components in the Porsche. This wasn’t really necessary, but it was interesting to see how much faster you take apart the second Leaf.

We named the endeavor “Angry Pixie Garage” and got some t shirts!

[bapshago]

We ordered our Zombieverter and spent a lot of time researching the settings we would use as well as documenting how we would wire the test best. We ordered buttons and switches for our test bed and some second hand control cabinets from HGRINC. Once the ZV arrived we build out the drive train along with the cooling system outside of the Porsche.

[bapshago]

The Nissan Leaf wiki on the openinverter website made the configuration and the wiring easy. Thanks to the authors. Next up was making room for the motor in the Porsche by removing the battery well and the spare tire well. We strapped the motor and gear box in to its approximate location and mocked up brackets using a Sketchup to .dxf workflow. We then cut out wood prototypes on the laser cutter and glued them together with a hot glue gun. This was a highly iterative process but gave us the confidence to order the metal components on sendcutsend. Once those pieces arrived we welded them up and test fit. We tried to use all of the existing leaf motor mounts but it ended up working better with off the shelf LS aftermarket motor mounts. We were able to use the front motor mount and brackets from the leaf mated to an adapter plate. This adapter plate connects to the existing transmission mounts. We also used the rear seatbelt locations to reinforce this bracket.

[bapshago]

Before I pulled out the transfer case and the transmission of the Porsche I measure the attachment points of the transmission to CV joints. I took these measurements on all three axis (X,Y and Z). I also knew the transmission was 12” wide. We were lucky because the Nissan Leaf CV cups were very close to 12” apart as well. With the Leaf motor hanging on straps we lined up the approximate location of the gearbox and motor pair. The inverter and PDU would need to be offset from the motor because keeping them connected would require us cut a major component of the Porsche frame. With the gear box in place I cut one of the Porsche axles in half, ground off the stops of the Nissan Leaf CV cups (motor side CV connection), removed the Leaf tripods and axles and cut the Leaf axles to the correct size. To get the measurement we installed both Porsche axles to the wheel assemblies and the Leaf axles to the gear box. I cutdown some tubing and hose clamped it to the axles to spin the wheels and test clearances in different states of shock/spring height. We did end up adjusting the motor forward an inch and reordered a new connection plate for the forward motor mount. We had intentions of welding our own axles together to save money, so we made some v rollers to remove any runout from our new shafts. That plan ended up changing and we decided to spend the money and have Dutchman axles make us new axles.

[bapshago]

Around this point into the project we took on some side quests. My daughter is going to college next year for electrical engineering and we wanted to work on some of the ancillary electronics. Using inspiration from the forum and some GitHub projects, we build proof of concepts for a thermal control system that adjusts the coolant pump and fan speed using an ESP32 and CAN transceiver. It reads the to use the inverter temp CAN messages to determine optimal speeds. We also build a similar controller to look at engine rpm and adjust the Volvo electric power steering pump power. Lastly we build a web server that has an instrument cluster website that uses the CAN bus data for updates. Since the hardware was very similar in these projects we consolidated the design into one board that can be used for all three controllers. We called it the Angry Pixie Garage Uniboard. We have five made at JLCPCB and then refactored our software to run on the new hardware.

[bapshago]

Another side quest was the rebuilding of a better description would be the clean up of and the connecting of the Volvo power steering pump to the Porsche rack. We used AN6 fitting and bango fitting adapters to build the high and low pressure lines. Designed a bracket to hold the pump and then wired and mounted it in the hood.

[bapshago]

As mentioned the motor to inverter connection could not be a direct mate like it was in the leaf. We needed to move it back and to the passenger side a few inches to allow for clearance. We started this part of the project like the motor mounts, taking measurements and iterating on the design. Design the brackets, cut them on the laser out of wood, test fit the brackets and adjust where needed and we repeated that cycle until we feel we had a workable design. We again used our sketchup to .dxf workflow. Because the tolerances were so tight, this took a while. We had to consider the wire glands we were using, wire size, weldability of design, order of construction of the design, terminal connector shape and size of the wire, hv safety and proximity to surfaces that could cause an arc, and many other factors. We used phenolic sheets to allow for HV protection on the top of the motor and the bottom of the inverter to help stabilize the bus bars. We also had custom bus bars cut using sendcutsend. Once we were sure the design would work and we could put it all together, we ordered all the parts and welded it up. After another test fit and trimming, we painted the parts, crimped the wires and installed the motor to inverter connection plate and wiring.

[bapshago]

Even a blind squirrel finds find a nut. The Nissan leaf AC charging cable is the right size to fit through a hole made by Porsche in the rear frame rail next to the existing fuel fill port. We used Sketchup to CAD out a bracket to attach the Leaf charging port and extended the existing bolts of the filler door to build out the charging port. A 4” diameter exhaust coupler was the perfect size, a quick Amazon order that saved a few bucks. We had our design cut at sendcutsend and my daughter welded it up. She also put a coat of paint on it and for it to the car. An easy win! Hard to find in this project.

[maboyce]

Awesome project! If you haven't found it already, you might find this YouTube channel interesting - it's a 928 conversion project in Australia. They did a complete electronics and drivetrain swap from an MG.

[MattsAwesomeStuff]

A 928 build was one of my dream builds, but I think I waited about 5 years too long for "old junky" Porsches to still be cheap.

I love that the 928 is the luxury version of the 911, and was murdered by Porsche because it was stealing sales from their flagship car.

And I love that it has some degree of rear wheel steering.

Right after I bought my first donor car for converting (my Opel GT), a 928 that was already converted and just needed batteries came up for sale, for only $1000. I cried a little.

I love seeing a well documented build. Looking forward to your updates.

[bapshago]

@maboyce this channel has been very helpful with our project. The episode where they cut out the tire well and battery box to fit the motor helped us make the first cut.

[bapshago]

@MattsAwesomeStuff thanks for the comment. This car was headed to the scrap yard, so we feel like we are giving it another chance of survival.

[bapshago]

When the axles arrived from Dutchman we test fit them, removed them, greased them and then reinstalled them in the car. We also build out the cooling system. We used the motor, radiator, reservoir and hoses from the Nissan Leaf. We needed to purchase some clamps and hose barb couplers, but between the two donor cars we had enough hoses and the correct bends. The intention was to use the original Leaf fans; however, they were too large and just didn’t fit. We bought an aftermarket 7” fan and will add another one of cooling becomes a problem. The resolver was also required to accommodate the phase swap for running the motor in reverse.