Toyota MGR Rear Traction Transaxle

[Bassmobile]

The highest oil temps recorded under the most severe testing that ORNL conducted as sited in the report linked above by ZooKeeper were in the 80ºC range.

So any GL-5 synthetic high performance gear oil will be rated with a viscosity degradation temperature in excess of 120ºC and a thermal flash point (PMCC) @ 200ºC. The standardization of the methods for determination of performance specifications for API GL-5 Lubricants are defined in the most recent version of ASTM D7450 if you want to get scientific about the analysis.

Bottom line is that there seems to be no science supporting the need for and MGR oil circulation scheme, so long as a high quality lubricant is used, and regular PM schedules are followed. It would probably be a good idea to install a probe to monitor gear oil temperature when in operation.

references:
https://en.wikipedia.org/wiki/Pensky%E2 ... d-cup_test

[bexander]

Is there anyone how knows what type of temperature sensor is used in the MGR?
As far as I have measured it's a NTC type 47kohm or 50kohm thermistor.
I don't have any good idea of how to characterise the sensor over its whole operating range without disassemble the MGR.
Any ideas?

[ZooKeeper]

The highest oil temps recorded under the most severe testing that ORNL conducted as sited in the report linked above by ZooKeeper were in the 80ºC range.

However, the rotor temps were over 200*C and an MGR/Q211 does not have cooling loops like a Prius has. So for an EV drive, I would submit that testing is needed to establish actual fluid temperatures during operation.

[slow67]

Spraying oil directly on the windings and thru a cooler if it runs too hot.

[519 Kustomz]

Wonder if I could get some assistance with a couple dimensions for the RS axle stub shaft? (The long one) I’m just finishing up my adapters but I didnt have a stock right side to measure. Primarily looking for the diameters of the steps after the spline. First one should be 27mm dia. Also need the offset from the very end of the splines to the diameter changes. Greatly appreciated!

[UStas]

Now anyone could say how the rpm/V is? I really need 600V for reach the 50kW?

I`ve rewinded MGR from 42 to 10 turns and got 60 rpm/V. With 150V now give arround 9000 rpm.
Initially it was 12 rpm/V.

[Mouse]

I`ve rewinded MGR from 42 to 10 turns and got 60 rpm/V.

Did you take any photos of this process? I've rewound ebike motors but not considered anything as big as this.

[jalovick]

Spraying oil directly on the windings and thru a cooler if it runs too hot.

There are plenty of aftermarket diff cooling units that would do the job just fine, it's a matter of working out where the input and output bungs should be welded in or if existing ones can be used.

I have an MGR on order, so will test this sometime next near, as the cheapest place for me to get one is from Japan, shipped via container to Australia, wreckers/breakers/salvage yards here put a premium on hybrid parts. I'm sure someone else will beat me to it.

Jamie

[konstantin8818]

I was trying to design an adapter plate wich could be bolted to MGR output flange on one end and to BMW CV housing on the other end. Almost immidietly realised that it is impossible, or adapter plate must be thic and over complicated.
So I see two ways: cut MGR flange and weld BMW flange to it. Not cheap procedure but the most tidy one. The other option is cheap, yet rely on your welding skill, and this is to make as Damied did - cut schafts in the middle and weld them using metal sleeves.
I'm now going Damien's way.

[Mouse]

This sort of thing is not beyond the hobbyist if you have access to a lathe.
You could weld a plate to the MGR flange and then turn it to the dimensions of the BMW CV joint so it would just bolt on.
I did this for the last bike project I made using VW CV joints and it worked very well.

I've also welded a shaft for the same project with a little bit more finesse than Damien probably only because I've got a lathe in my tool kit
I did buy high tensile rods for this job.

The modified flange is in the left of the photo.

Modified flange and shaft. Been in constant daily use for 4 years.

[bexander]

I was trying to design an adapter plate wich could be bolted to MGR output flange on one end and to BMW CV housing on the other end. Almost immidietly realised that it is impossible, or adapter plate must be thic and over complicated.
So I see two ways: cut MGR flange and weld BMW flange to it. Not cheap procedure but the most tidy one. The other option is cheap, yet rely on your welding skill, and this is to make as Damied did - cut schafts in the middle and weld them using metal sleeves.
I'm now going Damien's way.

What is the PCD of the BMW flange?

Here is how I did to adapt MGR to small VW flange. Maybe you can do something similar?
viewtopic.php?f=11&t=912#p14765
viewtopic.php?f=11&t=912#p16959

[konstantin8818]

What is the PCD of the BMW flange?

It's 80,1mm.
Unfortunately for now I haven't got my own lathe. Flange I've designed was pretty similar to yours. Lathe operator said it would be expensive one. To cut MGR flange and weld BMW one to it would be cheaper, yet the most cheap way was to buy two drive schafts from Lexus and to make two sleeves.

[JFJ]

Short picture series showing how you can shorten and reuse the power plug. The copper tubes is made from 12mm water pipe and fit perfect when crimped with 35mm2 jars on my YKQ-70 crimp tool, I advise on of those, low cost and fine quality, I would not like to make EV cables without a hydraulic Crimping Tool.
I have used EMC Grounding Glands size M20x1.5mm that can handle the 14mm shielded 35mm2 cable I use in my build.

[TheSilverBuick]

You're the second person I've seen this week use copper pipe to make crimped cable ends. Nice!

[konstantin8818]

You're the second person I've seen this week use copper pipe to make crimped cable ends. Nice!

Look closely how factory cable ends are made. Those being sold at electronics shops. They are also pressed from pipes.
Off topic: desided not to cut drive schafts, but bought two hub assemblys from RX400h. They are designed almost perfectly to be fitted to long travel buggy suspension

Also have seen another Lexus MGR on sale for 30 bucks, can't resist to buy it AWD is closer then it looks...

[ZooKeeper]

Short picture series showing how you can shorten and reuse the power plug.
I have used EMC Grounding Glands size M20x1.5mm that can handle the 14mm shielded 35mm2 cable I use in my build.

Great minds think alike, at least I think so

[konstantin8818]

Interestin observation: I've connected my second MGR to inverter without changing any parameter and it spins
It jitters but doesn't run away. So that means for MGR you can start syncofs tuning from 22000 and just tune it a little for motor to run smoothly.
Video is in Russian, but there is nothing, you guys don't know

[ZooKeeper]

Interestin observation: I've connected my second MGR to inverter without changing any parameter and it spins
It jitters but doesn't run away. So that means for MGR you can start syncofs tuning from 22000 and just tune it a little for motor to run smoothly.

Yes, interesting. I tried SO near 22k and could not get good results, ended up about 1/2 of that at 10975.

[konstantin8818]

Yes, interesting. I tried SO near 22k and could not get good results, ended up about 1/2 of that at 10975.

Weird

[ggeter]

New member -- thanks for the patience.

Looking at a 1979 Midget for $1000. Thinking about an MGR unit in engine bay, turned sideways, with one output bolted to existing driveshaft and the other output locked so that it can't spin, so that open diff sends all power out the side bolted to the prop.

Does this sound feasible? This will be my first project, and although a GS450H unit would be wild in this car, hoping to get rolling quickly and learn as much as I can.

Thoughts?

GGeter / Houston, TX

[Mouse]

Hi GGetter,
The actual planetary differential gears and bearings are not meant for continuous rotation so locking one side and the other spinning twice as fast will be very short lived.
However welding the differential gears up like a lot of amateur rally cars to get the same rotation from both sides is reliable and also currently implemented in my current vehicle.
The important thing is to consider the overall gear reduction of mixed and matched parts.
Regards
Russ.

[ggeter]

Thank you, Russ. So, my two options are to 1. weld the MGR diff, attach to existing prop, and drive the MG current diff (3.7 ratio) which would mean more torque, but lower speed at the wheels, or; 2. mount the MGR between the rear wheels in place of the existing diff. I can cut out the existing rear diff, maintaining spacing, etc. May take some time, but perhaps the best option.

I think option 2 may be the way to go from a final drive feasibility perspective.

-g.

Hi GGetter,
The actual planetary differential gears and bearings are not meant for continuous rotation so locking one side and the other spinning twice as fast will be very short lived.
However welding the differential gears up like a lot of amateur rally cars to get the same rotation from both sides is reliable and also currently implemented in my current vehicle.
The important thing is to consider the overall gear reduction of mixed and matched parts.
Regards
Russ.

[UStas]

I`ve rewinded MGR from 42 to 10 turns and got 60 rpm/V.

Did you take any photos of this process? I've rewound ebike motors but not considered anything as big as this.

Not so much a photos.
I forget to do it all the time

You can see more about my project, but russian only here - https://electrotransport.ru/ussr/index. ... 5.0#topmsg

[ZooKeeper]

Thank you, Russ. So, my two options are to 1. weld the MGR diff, attach to existing prop, and drive the MG current diff (3.7 ratio) which would mean more torque, but lower speed at the wheels, or; 2. mount the MGR between the rear wheels in place of the existing diff. I can cut out the existing rear diff, maintaining spacing, etc. May take some time, but perhaps the best option.

I think option 2 may be the way to go from a final drive feasibility perspective.

Option 1 would get you a TOP speed of 25-35 MPH (27% of MGR output RPM to the tires)

Option 2 works well for a vehicle with axle shafts, but not so well where there was/is a solid axle as it requires a LOT more fabrication.

[Damp_Cuttlefish]

Hi Guys, another first time poster here so bear with me.

I think I've found myself in the same tricky position as GGeter.
I was planning a conversion with an Outlander PHEV rear diff assembly, the vehicle has a solid rear axle with a 4.1:1 diff so the plan was to lose the diff and reduction assembly and attach motor straight to propshaft (or gearbox just to get started).
Unfortunately in a wooly headed moment I saw a Lexus MGR going cheap and though "Hey, that looks pretty similar spec to the outlander, why not?" completely forgetting what I actually planned to do with it

I'd like to go a bit over 30mph, my fabrication skills aren't up to the job of splicing it into the existing axle (Nevermind the unsprung weight) and I don't fancy shelling out for a new motor just yet.

Options I'm considering are:
1 - Hack the casing apart, take a shaft straight off the motor then find a way to keep it cool and stop it pissing oil everywhere.
2 - Lose the casing and make a new one for just the motor
3 - Rewind the motor for silly speed and hope the gears can take it
4 - Accept defeat, use this as a test motor and swap for something more suitable when I've got the rest of the build worked out

Can anyone familiar with the MGR guts offer any words of wisdom?