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Discussion Starter · #1 ·
Hi folks. Just started to plan for my 1993 MR2 conversion. I'm a Toyota engineer full time working on their fuel cell semi's so a BEV seems comparably simpler.

Where I stand: I have an MR2 donor with good body and no rust. It came stock with the 3SGTE, so the trans and CVs should be able to handle some extra immediate torque. I like the idea of keeping the stock transmission because shifting is fun.

With a little searching I came across the EV west MR2 conversion kit here but I don't love everything about it.

Right off the bat here's my initial feelings:

Pros:
Comes with lots of necessary components that match together well
Trans adapter plate fits with my existing hardware
Professional support from EV west for integration

Cons:
Not incredibly powerful motor
Seems to be a very high markup for parts compared with other sites

So here are my current questions:
1. Does anyone have experience with this kit? Do you like it?
2. How do yall like the HPEVS AC50? I don't need much power but it would be nice to spin the wheels every once in a while. I doubt it will beat my roommate's kitted out MR2 turbo in a 1/4 mile, but that doesn't mean I wont try.
3. Any experience working with EV west? How is their customer support?
4. Has anyone registered an EV conversion in Michigan? I have seen some real shitboxes on the roads so I don't expect troubles. But I dont want to get 6 months into the build only to find out I cant drive it to work.
5. The trans adapter plate sold by EV west seems like it has compatibility with several 'C Face' style motors. Is this an industry standard connection method? And does this mean that all primary motor support will come from the transmission as in no extra mounts needed?

Thanks in advance for all the help. This is a long term project so the first few months will be all just planning (and maybe painting the car)
 

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I'm a Toyota engineer full time working on their fuel cell semi's so a BEV seems comparably simpler.
That's certainly true! On the other hand, packaging components into the available space will be a much greater challenge. Placing bulky battery modules like that stack of fuel cylinders behind the cab of those trucks is not an option.

5. The trans adapter plate sold by EV west seems like it has compatibility with several 'C Face' style motors. Is this an industry standard connection method? And does this mean that all primary motor support will come from the transmission as in no extra mounts needed?
Yes, face mount patterns developed by NEMA are industry standards... in the electrical industry, not just EV conversions. Those motors are face-mounted; some conversions add other mounting arrangements, some of which are likely structurally questionable. Since two of the three mounts of the combined engine and transaxle are usually on the engine, and the motor is not designed with mounting points other than the face, some additional structure is required.
 

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Discussion Starter · #3 ·
Yes, face mount patterns developed by NEMA are industry standards... in the electrical industry, not just EV conversions.
That is very good to hear. Thanks Brian.

Battery location/size is still obviously a big question. I've seen them do it below the trunk in the rear of the vehicle. But that seems like a very small area and also would mess with the weight distribution of an already tail happy car. So still a big decision.
 

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I'm a Toyota engineer full time
The Open Inverter forum is particularly invested in repurposing old Toyota and Lexus parts, I bet you'd have interesting tidbits to advise them with there, if you're looking to volunteer.

3. Any experience working with EV west? How is their customer support?
Sales support is great. They'll answer right away if they're selling you something.

Product support? Abysmal. Will ghost you for months. Will sell you used products that are broken and then want you to spend your time and money diagnosing them to fix them. One user here (Snowdog) bought a kit from them, and basically gave up after dozens of attempts to communicate with them any possible way. Was given the run-around and told to try BS like removing all his pins and replacing them with gold-plated ones (on faulty hardware they sold him) and other crap like that. The end resolution was no resolution. He just threw in the towel, gave up, and bought replacement from a different company. I think literally every part they sold him was malfunctioning.

EV West used to have a stellar reputation here but in the last few years it's plummeted. I would certainly avoid.
 

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@MisterToo
If you are still checking back here... I hope you are, and still pursuing this project. I think you will learn a lot about Toyota's best years of engineering and production quality working on this car, and how that compares to the quality of some of the DIY EV parts you may encounter in your build.

Behind the rear axle is certainly bad, but up front is bad, too. Stacking masses at the ends of a short-wheelbase car is always bad.
Good point. Though being an MR2, and depending on the battery size, I believe the batteries will need to be distributed about the car including the front trunk and a bit behind the rear axle. Most should go in the fuel tank tunnel and in the engine bay. Any extras, if needed, can then migrate towards the ends of the car. I haven't looked at a second gen MR2 for a while, but some of the frunk on my '85-89 generation cars is still behind the front axle line.

I once loaded my AW11 Mr2 with approx 20kWh of LiFePO4 cells to transport them, many in the frunk, some in passenger side floor, some in trunk, and it really handled like crap. Your generation is a bit heavier to begin with so should take it better. Expect some handling compromise either way with your additional battery weight, but before starting your disassembly get some scales and find out stock distribution. Then with engine and fuel tank removed, fill the car with batteries (if you have access to some) or other weights, like brick clusters wrapped in packing stretch wrap. Frunk, on top of center tunnel above fuel tank, engine bay, trunk above your exhaust area... try to get things to a similar weight distribution. Also account for your electric motor, controller, 12V battery, and charger weights.
I spend all of my EV time with LiFePO4 batteries so I am most comfortable with them (*sets beer down on 200AH cell coaster), and would use them if I decide to convert an MR2 in the near future (still on the bucket list). With salvage modern production EV parts around you will probably be encouraged by other members to use a battery chemistry with higher energy density vs weight/size for this particular car.

Thanks in advance for all the help. This is a long term project so the first few months will be all just planning (and maybe painting the car)
At this point I would only get the car to a blocked and primed state if you plan to paint it. You will be doing all kinds of terrible things to it between now and when it reliably hits the road, including but not limited to: Cutting, grinding (put tape on your mirrors and mask your windows now to be prepared ;)), dragging cables across the body, repeatedly installing and uninstalling parts, having tipsy "helpful assistants" lean on and bounce tools/parts against the body, etc.
Have you bodyworked/painted a whole car before? If no, don't do this one right now. Polish it if it makes you feel better.

Will sell you used products that are broken and then want you to spend your time and money diagnosing them to fix them.
Wow. Yeah skip that kit. Clearly reselling 90% other company's stuff. If you want some of those components shown but in used or slightly broken condition with better support for pennies on the dollar, hit me up!!

Those motors are face-mounted; some conversions add other mounting arrangements, some of which are likely structurally questionable. Since two of the three mounts of the combined engine and transaxle are usually on the engine, and the motor is not designed with mounting points other than the face, some additional structure is required.
(y)(y)(y)
EVwest's kit says all you need to add is batteries etc, but fail to mention the lacking motor mounts that will need to be custom made. For someone like me who is better equipped to build electrical components at the moment, that has left me at the mercy of other local help's timeline or quality. Here I sit with the adaptor plate that comes with the kit you have shown, but also is not shown in the kit page (I purchased from CanEV. If you look at EV west's motor adapter pages for the Toyota S engine adapter, the description text is pasted from CanEV's site - before something terrible happened to their webpage recently). I am waiting for a fabricator friend to complete these custom motor mounts for my '97 Rav4 conversion. The Rav had the 3SFE that shares a block and bellhousing design with your 3SGTE. At this point I need to note that the 3S motors came with two different flywheel bolt patterns, IIRC the turbo'd motors and/or the 3SGE, and some late run 3SFE engines had a different pattern than what that hub adapter will have. CanEV should be able to provide you the drawing that I used to confirm that mine was the correct one, now that the website has lost its content.
Back to brian_'s point. The AC50 also has 1/2" threaded holes on the tail end which makes it immediately tempting to build a quick tail end motor mount to complete the motor/trans installation, but the structural differences between a 3S block and AC50 which is basically a steel 8" pipe with 1/8" thick walls, held together with only 4 really long 1/4"-20 bolts is like.... cant even find a comparison right now. You need to build something really strong that ties the closest-to-face available motor mount location to the tail end of the motor, and then to the factory tail end (engine pulley side) mount on the body. Sorry if that wording is confusing.

1. Does anyone have experience with this kit? Do you like it?
No experience with the kit, but you won't need the shunt if you select a good BMS that handles battery current, such as Orion or others.

2. How do yall like the HPEVS AC50? I don't need much power but it would be nice to spin the wheels every once in a while. I doubt it will beat my roommate's kitted out MR2 turbo in a 1/4 mile, but that doesn't mean I wont try.
You will be disappointed if expecting overall performance comparable to the stock engine. Between traffic lights it will be good, but 96V Curtis wont get you competing with your bud, bud. Also most will say that they are old school and obsolete. If you are like me and crave era-true Alpine stereos for your old Japanese cars, maybe it could be a similar concept.
That said, I have worked with HPEV AC-50 and Curtis 1238 96V systems for about 10 years and they are very very reliable if used in a well designed build.
If you are keen on AC-50, maybe take a look at the power graphs on HPEVS' site, the 144V controller may be worth looking at.

Again, if you are still here, cheers from a fellow 'Yota man
 
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