Toyota MGR Transaxle - Alternative Orientations?

[Matthew Dresser]

Hi,

I'm at the easy stage of my project at the moment: ripping the crappy old ICE out of my car


https://imgur.com/gallery/l4ckLr4


I'm planning to put in its place the MGR unit from a Lexus RX450h. I have a feeling that it's not going to fit very well in its usual orientation (motor forward of axle line). What would happen if I mounted this thing the other way around and ran it in reverse?
Alternatively, if I mount the unit in the correct direction, how much of an angle can I get away with on the CV joints?

Thanks!

[sfk]

The MGR depends on running forward for lubrication. The differential "slings" fluid from the lower pool up into a distribution reservoir where it trickles down through various passages back to the bottom. Running it in reverse or not horizontal will prevent lubrication.

The CV joints will tolerate some displacement. Less is better obviously.

[Matthew Dresser]

Thanks for the reply @sfk
I watched this video and he mentioned about the oil lubrication mechanism also.
I heard some people mention about providing cooling to this motor by circulating the oil through a water/oil heat exchanger. Perhaps if some oil pump was added with a new input port strategically added, it could allow this system to work running in reverse?

[sfk]

Yes you could probably make it run in reverse if you put a port near the bottom, an oil pump and then probably a cooler (the MGR isn't intended to run constantly, just add rear traction when needed) and then a port near the top to fill that reservoir.

I assume you have a Q211 MGR trans

Q211
· Layout - 3-shaft type
· Electric motor - 2FM (50 kW / 130 Nm or 139 Nm), with permanent magnets
· Gear ratio - 6.859 (1st stage - 23:40, final gear - 18:71)
· Capacity - 1.8 l (ATF WS)
· Module weight - 41.8 kg

1 - fluid catch tank, 2 - differential ring gear. a - fluid slung, b - MGR lubrication

1 - motor generator (MGR), 2 - counter drive gear, 3 - counter driven gear, 4 - differential drive pinion gear, 5 - differential ring gear, 6 - differential gear unit, 7 - differential side gear shaft. a - to left rear wheel, b - to right rear wheel

Model Production
Alphard/Vellfire ATH20 2008-2015
Alphard/Vellfire AYH30 2015-..
Estima AHR20 2006-2019
Harrier MHU38 2005-2012
Harrier AVU65 2013-..
Highlander MHU28 2005-2007
Highlander MHU48 2007-2010
Highlander GVU48 2010-2014
Highlander GVU58 2014-..
Kluger MHU28 2005-2007
Lexus RX400h MHU38 2005-2008
Lexus RX450h GYL15 2009-2015
Lexus RX450h GYL25 2015-..
Lexus NX300h AYZ15 2014-..
RAV4 AVA44 2015-..

[sfk]

With your rear engined Fiat 124 I would be more inclined to try keeping the gearbox and driveshafts and just mount a Nissan Leaf electric motor in place of the ICE. Wouldn't it be a lot simpler??

More info about Toyota MGR's here -
https://toyota-club.net/files/faq/19-10 ... wd_eng.htm

Q211 is the most common and most powerful

[Kevin Sharpe]

Look out for Damien's "Blue Yacht" project which is designed to test the limits of the MGR on the road

[Matthew Dresser]

Oh cool will be watching that eagerly! Nissan Leaf motor would be pretty damn powerful for a fiat 126 - but quite pricey surely? Wouldn’t I be looking at around £1K ?

[Matthew Dresser]

How feasible would it be to saw the unneeded parts from a Prius transaxle and mount that to my fiat gearbox?

[konstantin8818]

How feasible would it be to saw the unneeded parts from a Prius transaxle and mount that to my fiat gearbox?

In Russia one guy already did it back in 2016.
Here is his profile on russian forum: https://electrotransport.ru/ussr/index. ... le;u=28011 However he is not active for over two years.
Here is photo of his sawed gen2 motor:https://drive.google.com/file/d/0B20j3E ... VCNTg/view
https://drive.google.com/file/d/0B20j3E ... tzWjQ/view
So apparently it is possible=)

P.S. In the same thread in 2017 the other guy showed this video of Estima MGR being operated by gen2 prius invertor:
https://drive.google.com/file/d/0B9oHiL ... d0STA/view
2350 rev/minute ~300km/h without load

P.P.S. here link to a thread where in the bottom of the page there are three videos from man who sawed and rewinded MG1 from gen2 gearbox and used it as boat motor: https://electrotransport.ru/ussr/index. ... 360#topmsg

[sfk]

Oh cool will be watching that eagerly! Nissan Leaf motor would be pretty damn powerful for a fiat 126 - but quite pricey surely? Wouldn’t I be looking at around £1K ?

Yes it would be quite powerful but you could easily limit the inverter output to protect the gearbox.

The motors themselves are quite cheap to buy. It's the batteries people want.

[Matthew Dresser]

@konstantin8818 that looks really interesting!

@sfk thanks for the detailed info - very interesting stuff there. Looking on eBay I don't see Leaf motors below about 700 GBP is that about right, or do I just need to wait for a better deal?
I'm thinking that 1) I would need some sort of oil cooling for continuous use of this MGR anyway, so it probably won't be much more effort to drill another hole for an oil input somewhere. One thought though, running helical gears in reverse would cause axial loads on the gearbox in the opposite direction to what it's designed for. Need to check if the bearings are the same on both sides of each gear...

Heres a pic of the MGR being moved into approximate place in the intended orientation:

Basically, that's a big fat NOPE. Unit needs to be about 20cm further forward for driveshafts to be anywhere near in line.

And here we are with MGR turned the wrong way around:

More doable, but still only just fits!

https://imgur.com/gallery/C1YIVMp

[konstantin8818]

Might be helpfull information about oil inside MGR:

Oil around final drive gear is like a milk shake during movement. Air bubbles might damage oil pump and also they make it harder to cool down oil itself. So if you going to drill intake at the bottom of differential, make it as far from final drive as possible.
My idea is to not to drill anything, I want to replace oil check plug with intake tube plug and make cooled oil return through fill plug, so it will mix with oil slinged by final drive and go to the motor.

[arber333]

My idea is to not to drill anything, I want to replace oil check plug with intake tube plug and make cooled oil return through fill plug, so it will mix with oil slinged by final drive and go to the motor.

Be carefull even with the oil plug. It is located at the bottom of the oil pan. All sorts of filings and solid pieces are traveling inside oil stream. I would recommend you make an oil out hose and in the lowest part of the hose install a drum shape container with two hoses on same side. That will act as separator for hard parts. They must not come to your pump because they will damage it. Maybe you can also mount a magnet on the lowest part of container.

[konstantin8818]

Be carefull even with the oil plug. It is located at the bottom of the oil pan.

I'm not talking about oil drain plug, which is under final drive. If you watch closely WeberAuto video from first page, you can see that oil check plug is at front of case right under oil catch. Im going to isert a probe through there with metal net attached as filter. (BTW professor Kelly confused front and rear of MGR)

[Kevin Sharpe]

Unit needs to be about 20cm further forward for driveshafts to be anywhere near in line.

Drive shafts don't need to be in line

[konstantin8818]

Drive shafts don't need to be in line

But it is highly recommended. CV joints will heat up more with more angle. Efficiency is the key. Especially in EV.

[Kevin Sharpe]

But it is highly recommended. CV joints will heat up more with more angle.

If you watch a video of a drive shaft on a vehicle as it drives down the road you'll soon realise it spends almost no time 'in line'.

Efficiency is the key. Especially in EV.

Have a look at BEXUS... 2 tons of BMW heavy metal... if you undertook our course you'd quickly learn that we don't sign up to the efficiency mantra now that we have OEM parts and large capacity batteries.

[konstantin8818]

If you watch a video of a drive shaft on a vehicle as it drives down the road you'll soon realise it spends almost no time 'in line'.

But from the factory drivetrains are designed to work as close as possible to a straight lane. Offroad slow vechicles aside.

if you undertook our course you'd quickly learn that we don't sign up to the efficiency mantra now that we have OEM parts and large capacity batteries.

Yep, you guys are on another level
I believe Matthew Dresser's project, on the other hand, is aimed at low cost and efficiency. I might be wrong.

[Kevin Sharpe]

If you watch a video of a drive shaft on a vehicle as it drives down the road you'll soon realise it spends almost no time 'in line'.

But from the factory drivetrains are designed to work as close as possible to a straight lane. Offroad slow vechicles aside.

A CV joint does not distinguish between movement in the vertical or horizontal direction. I suggest you wait for the Blue Yacht project where we'll demonstrate this in the real world

[konstantin8818]

A CV joint does not distinguish between movement in the vertical or horizontal direction. I suggest you wait for the Blue Yacht project where we'll demonstrate this in the real world

I might not really correctly express myself. It's really hard to do it in English.
As an engineer I studied all types of automotive mechanics, and I know that CV joint designed to be used in most vide angle with as less oscillations as possible, but it is not ideal. None of any mechanical assembly is ideal. Movement create resistance. Resistance create heat, heat destroys lubrication. Lack of lubrication destroys mechanism. So engineers try to design any mechanism with as less unnecessary movement as possible.

For a daily usage it is might be not relevant as long as you don't care about those few kilometers per charge and few thousands kilometers of CV joint life.

In this particular case it is better for CV joint to be bent, rather then MGR being placed backwards.

[slow67]

I think the point Kevin is trying to make, is that majority of cars the the CV axle isn't straight at ride height. His point is that the CV axle can be the same amount of degrees forward as well with no additional wear/tear.

[SciroccoEV]

Unit needs to be about 20cm further forward for driveshafts to be anywhere near in line.

Drive shafts don't need to be in line

In fact, they shouldn't be perfectly in line. It causes premature failure of the joint as all the load and wear is in the same place, rather than spread out. For example Mazda MX5 propshafts are too straight and the UJs get 'notchy'. Not usually a problem on shafts subject to suspension movement.

Having said that 200mm (8 inches) of offset sounds like it would create quite an angle in the driveshafts, which is going to be less efficient and increase wear (general wear, rather than localised). Joint dustboot failure can also be an issue.

[clanger9]

All things being equal, I'd prefer to wreck driveshafts rather than a transaxle. Driveshafts are cheap and will take a surprising amount of abuse...

[SciroccoEV]

I knew something was nagging at my memory.

The 126 doesn't use CV joints at the outer end, it uses a flexible rubber joint;


They're not going to be too happy running continuously at larger angles.

[clanger9]

Ah. I see what you mean. Those will give up the ghost very quickly if run at a significant angle...