[DRIVING] Project RX8 , Prius gen2, Lexus transaxle to rwd

[Ev8]

You won’t need all those opto isolators, only on the digital inputs

[Ev8]

If you were in the uk I’d give you my board to copy, I’m about to embark on the AC conversion as even with the settings turned down I’ve managed to burn the commutator and brushes,

Anyway I pulled apart a Lexus rx400h transaxle today that I picked up for next to nothing, I plan on making modifications to couple mg1 and mg2 permanently, remove the output gears and use the input shaft as the output then modify the case to trim the bits I don’t need anymore, sounds like a lot of work but should be be fun

[celeron55]

An interesting choice - you really can get a serious amount of motor for almost no money. Interested to see the work involved.

[Ev8]

So project build a motor from a Lexus transaxle because it was basically free has begun in some kind of fashion this week, lots of cutting and swearing at my ugly ass ally mig welds later and we have a case minus differential,

Some tiding up to do and sealing the welds from the inside, then internal coupler between mg1 and mg2, coupler from input shaft to RX8 gearbox and external oil pump as it’ll be spinning backwards and hey presto a 222kw motor or something like that

[Ev8]

Frankenmotor update time, I have finish all modifications to the cases, sealed the internal welds with epoxy as there where some pinholes and I don’t want oil leaks, cleaned and rebuilt with mg1 and mg2, gutted the oil pump and modified the pump housing to provide pickup and feed locations for an electric oil pump (soon to be repurposed power steering pump) machines up a coupling piece from steel to join various parts from the 2 planetary gear sets to make a coupling between mg1 and mg2 and lock the input shaft to become an output, cleaned all the parts and held in place in the lathe ready to weld, attached my drill to the lathe motor pulley and set everything in low gear so it was slow enough to weld,.. welded everything up now I’m just waiting for things to cool down to se if we have a successful part

[Ev8]

And the answer is no, something pulled of square while welding

[RetroZero]

Sorry to hear that. It's looking seriously frankenmotor

[Ev8]

Is it possible to move these recent posts to the Prius gen2 dc motor controller thread maybe?

[Ev8]

So as I’m just coming to the end of a customers mk1 golf build (petrol engine I’m afraid) I have had the odd bit of time here and there to revisit the Lexus frankenmotor idea, obviously the modified case was done and good before but I had issues internally coupling mg1 and mg2, when I welded things they were no longer straight, so I have moved to making a new coupling which is all fitted together with shrink fits, press fits and pins to avoid heat distortion from welding, good news is it’s all assembled a spins smoothly.

[Ev8]

Moving onwards with the adapter plate,
I had this plate cut some months ago to match the gearbox, but with A lack of any accurate way the measure the location of the motor bolt holes I designed in a center section which will be cut out afterwards, and turned up an aluminium sleeve that fits on the motor output shaft to locate the plate centrally, holes will be then marked with transfer pins screwed into the threaded holes and transfer punches through the bolt holes. But now I’m out of the country diving for 3 weeks so next update will be a month or so!

[Ev8]

So a fairly log time with no updates but I’ve managed a bit of work here and there, adapter plate between the Frankensteined motor and gearbox is done, all the motor side holes drilled and countersunk and once I was happy with alignment I’ve cut the centre out of the plate and removed the aluminium shaft extension used for centering the plate, gearbox dropped on top to test fit. Now on ways to making the coupling.

[Ev8]

This week we have a shaft coupling

[Ev8]

Oh and I did a short vid through the bellhousing

https://youtube.com/shorts/OiceSuTFlrQ?feature=share

[Ev8]

DC-AC conversion moving along at last

Might need something other then wood for the engine mounts

[Ev8]

Made a start on over engineering some motor mounts picking up from the motor and the adapter plate

[Ev8]

Second mount fabricated and the motor is off the wooden blocks

[nkiernan]

Nice job

[Ev8]

Thanks, wish I had more time using my tig welder, feels like I get a reason to use it once every couple of years and it’s like learning all over again, I could have made these mounts in 1/4 of the time if I’d just migged them up! Maybe I’m putting off the electronics work I need to get on with!

[Ev8]

Motor mounts all finalised painted and fitted, I made up a front mount to pick up on the large lug on the end of the casing as it was one of the original transaxle mounting points, seemed rude not to use it, I ran out of argon so this mount is all mig welded together, I used a polyurethane bush I had laying around from something else,

I have also tried the to mock up mounting the inverter directly above the motor but it seemed like none of the mounts on the inverter were anywhere need any useful mounting points on the motor, making something to work was looking at being a couple of days work, so the inverter if going to go where it was before in the front as I already have mounts made for there and cooling pipe work in place, it means longer motor cables though, I’m hoping this won’t be a large problem

[Ev8]

So inverter is back in, HV wiring mostly done, as I’ve ditched the boost inverter I’ve used the space inside the inverter to house the maintenance contactors and precharge,

I few bits here to finish up and then I’ll move onto the next job to put off actually putting the 2 gen2 controller boards in 1 housing and wire it all up instead I’m going to revisit the motor oil pump, I was going to use an external electric pump as the original pump spins the wrong way, but now I’m looking at tue spare pump I have here and thinking I may have a go at re arranging the port configuration.

[RetroZero]

Great work and modifications. Are the contactors inside the inverter for anything else than space? I thought closer to the battery pack was better as to not have permanently live HV cabling.

[Ev8]

Thanks for the positive comment,
Mostly it seemed convenient , ideally I would have them at the battery but the pack is in 2 halves, half in the boot half under the inverter, there is always going to be some potentially live cable, I may add a second negative contactor at the rear pack to prevent there being a long run of cable with a large potential difference

[RetroZero]

. Keep it up, looking good. I like the 222Kw potential you are exploiting from the Lexus. I'm interested in how you connect the 2 boards in parallel (I will be doing it to the Prius transaxle)

[Ev8]

One board will be taking the throttle pot input, controlling mg2 and mapping throttle to can, second board will be using the can throttle value to drive mg1, seems to be essentially what is done on damiens twin motor gen3 board except over 2 boards, only slight issue I may have is the 2 WiFi’s clashing, I’m sure I’ll figure something out when I get there

[Ev8]

Ok one oil pump with ports reversed to run backwards coming up

Maybe not the prettiest solution and the feed the the pressure relief valve is via a stainless tube pushed through the middle of the new inlet route but I’ve tested it with a spare end housing and shaft in a drill and it works so that’s one less electric pump to run