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Hi,
I am currently working on a build plan to mount a Tesla Small Drive Unit to the rear of a Landrover Freelander 2004 V6. The plan is to have about a possible 200hp from the motor.
Problem is the space at the rear allows me to only mount it back to front meaning since speed in the reverse direction is low(or not a great idea) I am left with the option of mounting it upside down.

Questions:
1. What is the risk of installing the Tesla SDU upside down apart from oil cooling challenges that might arise?
2. What other motor options can give the same power/weight/size as the Tesla SDU?

 

[brian_]

Would you have the option to mount a Front Small Drive Unit rather than a rear Small Drive Unit. That changes the differential from the front to the back.

No, it doesn't. The Model S and X drive units all have the motor behind the axle line... front, rear, small, and large.

 

[4G63T]

If you need a drive unit so that axle faces toward the rear of the car, I would suggest waiting for the Model 3 drive unit to be available in the near future .

I am also looking for similar orientation , model 3 drive unit . I emailed EVWest a month ago and they said they are working to have it available in the next couple months or so. I would suggest to wait and do it the way you want or need to . There is also 057 Technology / HSR Motors , I didn’t contact them yet to see if they will have one available soon too. But if you contact them let us know what they say.

 

[ViktorT]

You can mount it backwards so that your reverse becomes forward. You will need to have an external oilpump though as the one in the sdu only works in fwd mode. I think that is easier than mounting it upside down as you would keep the place of the oil level for suction. EV romania has done that in a vw golf

 

[Jack-Lee]

You could switch the tubes in the oilpump! I do this with a small rear drive unit and it works well. So you should switch two of the three motorphases and encoderphases, to turn this Thing in the other direction.

 

[ViktorT]

You could switch the tubes in the oilpump! I do this with a small rear drive unit and it works well. So you should switch two of the three motorphases and encoderphases, to turn this Thing in the other direction.

That is very interesting. Do you have any pictures?

 

[Jack-Lee]

The Oilpump is could turn reverse, only the direction of the oilflow change, so you could change the tubes and lets go. But an external electric Oilpump with a filter is better.
The Motorcables could be seen at the picture too.

 

[brian_]

View attachment 120021

That image was posted in the DIY Electric Car thread Tesla Small Drive Unit by chrishazell of ZeroEV. Do you have a photo of your own modification?

The Oilpump is could turn reverse, only the direction of the oilflow change, so you could change the tubes and lets go.

Can it? Is it a bidirectional gear pump which works just as well in reverse rotation?

 

[Jack-Lee]

@brian_
Sure, somewhere on my phone. Have to search through the thousands of pictures there. The picture here also shows where to start.
Unfortunately I could not open the oil pump without destroying it. However, flow measurements showed the same flow measurement in both directions with the same input power.

 

[brian_]

Unfortunately I could not open the oil pump without destroying it. However, flow measurements showed the same flow measurement in both directions with the same input power.

Good to know - thanks.

 

[Jack-Lee]

 

[4G63T]

^^ If I understand correctly, based on the pics and what your explaining; one would just simply swap the two hoses to run it in reverse ? I assume there is enough clearance for the hoses to cross, clear everything needed etc...

 

[Jack-Lee]

Yes, thats all.

 

[tks007]

Any idea how to decode drive unit serial numbers?

Don't know exactly what you mean? I'm able to login into the DU and extract them from a memory location....

You could switch the tubes in the oilpump! I do this with a small rear drive unit and it works well. So you should switch two of the three motorphases and encoderphases, to turn this Thing in the other direction.

This is a very nice contribution! Thank u! The phase and encoder are indeed the electrical changes need to 'fool' the design.

Is there a special place where you made this work in the inverter? because there are also current measurements going on?

How do you run the inverter?OpenInverter or Standard tesla? I'm trying to get one going but it looks like the IMMO is in the way...

 

[Jack-Lee]

I use the OpenInverter-Board. Works smooth

 

[tks007]

My problem is dutch TUV i fear. I need EMC then how do you go along that in germany?
Could we get a TUV documentation for openinverter? then we would be OK too in NL...?

 

[remy_martian]

You can mount it backwards so that your reverse becomes forward. You will need to have an external oilpump though as the one in the sdu only works in fwd mode. I think that is easier than mounting it upside down as you would keep the place of the oil level for suction. EV romania has done that in a vw golf

Cowboy (gypsy?) engineering.

The axial loads on the bearings change direction.

If you look closely, you'll see roller bearings in that diff. and I wouldn't be surprised to see roller bearings on the other gearbox shafts.

Those will FAIL because you are using them as thrust bearings by running in reverse constantly and at high torque levels.

To do it right, you need to change the roller bearings out for thrust bearings. You might get lucky to where the bearings can get swapped end for end, but I seriously doubt it.

 

[tks007]

Basicly what you say is that you need to flip the bearings too?
What you say is that they are xkN in one dir ection and ykN in another?

Flipping should do it then?!?

 

[remy_martian]

Not flipping them around

Exchanging and turning them

Thrust bearing / ball bearing swap with thrust bearing pushing out on the case.

I doubt the case is machined to be able to do that unless there was a really forward thinking design engineer on it.

My open case is on the other side of the continent, so I can't say for sure, but running in reverse makes those helical gears push out on their spindles in the opposite direction.

In reverse, the car is not going fast, loads are usually low, and miles driven is dozens maybe in the life of the car.

A rule of thumb I'd propose is if the car's gearbox makes a different sound in reverse, under load, the bearings are unsuitable for backwards operation.

 

[tks007]

I don't know i don't have a open DU to check, but in theory if the load has a direction of rotation then the bearing can be flipped...if you argue that i'm lost...by flipping the direction of rotation of the bearing you basicly undo the direction change. Think about it else there are 2 parts numbers for suchs bearings and there aren't because you can flip them to suit your needs.

The only thing that won't be the same is the play of the bearing. If the play is calculated in the distance between the spurr gears then now the distance will increase or be smaller/tighter but if that happens you will notice on driveing (noise) and its not allot but i must admit that the distance is very crucial for noise..