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Discussion Starter · #1 ·
Hi:
I'm just getting started with my EV conversion project and while I await the arrival of my donor car, I wanted to pick some brains here if that's possible about mounting the Tesla LDU.
I suspect I will be running into a similar issue that other mid-engine conversions encounter and that's with the LDU not fitting in the stock position of having the motors aft of axle insertion point. Instead, I will need to mount the LDU backwards and upside down with the motors closer to the front of the car (because of suspension issues).

  • I looked in this forum and found some folks talking about using a model 3 motor instead, or making changes to a Tesla SDU, but nothing LDU specific.
  • I KNOW this works because ECC in the UK have done several Ferrari 308 conversions with a similar problem. Ive asked them to see if they would be willing to share a few more details but it does sound like at a minimum, they used an external oil pump. I'm hoping these folks will be willing to answer some of my questions (esp since i'm geographically unable to be a customer of theirs) but just in case they dont, I wanted to open up a thread here.

Q: If the external oil pump is the way to go, what specs should I look for besides the obvious (12V, continuous duty)? I know there are lots of off-brands for all the kids throwing turbos on NA cars on a budget and needing scavenge pumps but will something like this offer sufficient pressure/flow rate?

Also, what's the proper flow (pump -> LDU -> cooler -> reservoir -> pump)?

Q: How do other people solve this issue?
Thanks in advance for your posts.
 

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Discussion Starter · #3 ·
Zero ev makes a reverse oil pump for the Tesla drive units, ev west I think carries the part aswell.

I couldn't find the EVWest version but if I understand the description, you basically swap pump gears into this housing, mount the Tesla LDU backwards but NOT upside down, and run the Tesla motor backwards to make the car move forward.

Do I have that right?
 

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Mercedes B series used a large drive unit made by Tesla that had the motor in front of the axle. Zero futzing with oil pumps. I'm guessing that's what your European secret handshake Ferrari society used.
 

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Mercedes B series used a large drive unit made by Tesla that had the motor in front of the axle. Zero futzing with oil pumps. I'm guessing that's what your European secret handshake Ferrari society used.
The second-generation (2012-2014) RAV4 EV, too. Both would be rare.
But the appeal of Tesla Model S induction drive units is mostly the aftermarket and hobbyist support for controls, and I don't know if that extends to these units; it if does, great. :) If you just want an EV drive unit with the motor ahead of the axle line, that's most of them... and the rest (other than Tesla) have the motor on the axle line.
 

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Don’t mount it upside down, at least 3 reasons

1 there is a vent on top of the gearbox that would leak
2 the pickup system for the fluid splasher would be high and dry (so getting the reverse pump would be pointless)
3 no way to drain the Trans fluid from gearbox
 

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Discussion Starter · #8 ·
Don’t mount it upside down, at least 3 reasons

1 there is a vent on top of the gearbox that would leak
2 the pickup system for the fluid splasher would be high and dry (so getting the reverse pump would be pointless)
3 no way to drain the Trans fluid from gearbox
Thanks for the feedback. I'll think about what you suggest (esp on #1 and #2).
FWIW, I'm not planning on using a reverse pump. Instead, I'll plumb in an external pump/cooler setup outside the LDU to force trans fluid through. Exactly how I plumb the external pump to the LDU is still TBD; I know its been done before so the vent may very well be the right point to have the fluid flow out (which would solve the issue with #1).
As far as #3, that one seems simple. Either disconnect the hose and let it drain out or disconnect the hose as it goes into the LDU and let the oilpump pump its guts out (just like using your fuel pump to drain your gastank).
 

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there are 3 holes for fluid in the gearbox: the vent, a threaded drain hole at bottom and threaded fill hole about 1/3 or 1/4 from bottom. Can’t remember if the vent hole is threaded or if the vent just snaps in to the hole. If upside down it seems like you’d have to use the vent to pull fluid out of the gearbox since it would be at the bottom.

No idea if you’d run in to other issues with coolant routing thru the motor and inverter.

you’d also have your HV cables pointing down toward the ground, probably not the end of the world but may be a disadvantage.


Thanks for the feedback. I'll think about what you suggest (esp on #1 and #2).
FWIW, I'm not planning on using a reverse pump. Instead, I'll plumb in an external pump/cooler setup outside the LDU to force trans fluid through. Exactly how I plumb the external pump to the LDU is still TBD; I know its been done before so the vent may very well be the right point to have the fluid flow out (which would solve the issue with #1).
As far as #3, that one seems simple. Either disconnect the hose and let it drain out or disconnect the hose as it goes into the LDU and let the oilpump pump its guts out (just like using your fuel pump to drain your gastank).
 

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New contributor here. I am doing a Tesla Boxster conversion using a Tesla "Sport" model from a P-85 LDU. It is mounted backwards with the Zero-EV reverse oil pump. You cannot operate the motor upside down due to the oil reservoir being at the bottom of the transfer case and the breather on the top.
 

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Discussion Starter · #11 ·
I haven't posted in a while since I have my build thread on ferrarichat since my conversion also involves tearing into a lot of model specific upgrades (coilovers, etc).

As I'm now getting into more EV specific questions, I suspect I'll be posting here more.
One thing you folks might find interesting/useful is that since i don't have a 3D scanner to do virtual modelling (and I'm not great at CAD even though I have several friends who are), I did find making a 3d print of a Tesla LDU to be super helpful. Since my buddy's printer bed was about 20mm too small to print each cross section, I ended up with about 30 bricks to glue together. Turned out great. Manipulating a 14ish LB chunk of plastic is a LOT easier than a 300LB LDU.

First Idea: mount LDU flipped / upside down and flipped (same issue)
Within a few minutes, it helped me realize that my planned original mounting scenario (with the windings of the motor forward of the gear reduction axle take-off) won't work as the axle take-off point interferes with the forward support of the strut top mount. Other folks run this LDU flipped/upside down by reversing the breather/reservoir holes and using an external pump. This discussion on whether that makes more sense OR just running a the reverse internal pump is academic for me because cutting this forward brace AND relocating the support was not ideal because I didn't want to risk accidentally shifting the shock top position/suspension geometry more given the already shimmed-to-hell italian engineering tolerances.



I then tried another idea that had its own issues about potentially mounting the LDU more vertical but the cons outweighed the pros

Pros
  • Easier rear battery box (just a big box area)
  • Fairly easy mounting (just a horizontal brace could hold the rear mount point easily
  • Weight still forward of the axle (mostly)
Cons
  • Even with an external oil pump, the oil intake/return holes on the stock LDU aren't in the right spot for proper cooling; I'd have to drill and tap the LDU body (biggest issue)
  • Higher CG compared to even the stock V8.

My new plan is to use the original Tesla configuration (windings behind the gear reducer)
  • I dropped the subframe and will confirm this today (after installing the rear coilovers to bring the height of the axles up to their proper "max drop" distance but it looks like a good chunk of the weight of the LDU will still be on the subframe.
  • the side/rear brackets might be a little more complicated to deal with but the rear battery box will be simple again since there's nothing else on the subframe.
  • I was worried about shifting the F/R weight too far back but the windings aren't too far back form the centerline of the rear axles (this won't be like a 911); in any case, I'll have a second battery box in the "frunk" of this car to offset this rearward shift




TLDR: if you don't have a 3D scanner to scan your engine bay/subframe, consider printing your own LDU model to help plan for mounting. It's worth the plastic.
 

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Or, you could simply survey how others did it to similar engine bay layouts:



Screenshot (he seems a bit slippery about showing this in greater detail, including disclosing the oiling mod):
Motor vehicle Auto part Gas Automotive exterior Car


TL;DR: mount the LDU bass ackwards. There's an oil pickup reverser kit from EV Zero, FYI, which I believe where this shop gets most of its stuff.

Putting the drive unit in the way you've proposed will mess up the handling of the car by significantly increasing its polar moment.

edit: in reviewing your pics again, looks like your firewall may prevent you doing this. I'll leave this up for other Ferrari converters
 

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Discussion Starter · #13 ·
Or, you could simply survey how others did it to similar engine bay layouts:



Screenshot (he seems a bit slippery about showing this in greater detail, including disclosing the oiling mod):
View attachment 128270

TL;DR: mount the LDU bass ackwards. There's an oil pickup reverser kit from EV Zero, FYI, which I believe where this shop gets most of its stuff.

Putting the drive unit in the way you've proposed will mess up the handling of the car by significantly increasing its polar moment.

edit: in reviewing your pics again, looks like your firewall may prevent you doing this. I'll leave this up for other Ferrari converters
Yes, this build was what made me consider buying a Ferrari for a conversion in the first place.
I've studied their pictures and went so far as to call them to find out what they did with their build. They were very cagey about how they did it. Yes, others use the reverse oil pump.
Here in the US, the E1 drift camaro uses an external oil pump and cooler and run it with the stock pump and it works just fine.

Automotive design Motor vehicle Rim Automotive exterior Auto part


At this point, I know I can mount it backwards. I'm no longer discussing this point.
It's not 100% clear what they did for this 308 build but it does seem like they modified the forward suspension brace.
What I'm working on now is deciding which is a better mounting point that does NOT require me to cut the subframe and reweld new bracing that is strong enough.



I have the rear coilovers mounted now so I can see the axle angle.
 
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