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Discussion Starter · #1 ·
Hi everyone.

I've been looking at using a Tesla LDU in an electric conversion. I see there are a handful of Tesla LDU "conversion" options, including openinverter, AEM EV, EV Controls, and 057 Tech (any others ?). And various sellers of converted LDUs using those controllers. Each with their pros and cons.

One thing I'm not exactly sure of (and can't find any explicit information on), is the actual differences between the Base and Sport LDUs. I gather that they are mechanically the same ? I assume that the ICBs (inverter control boards) are different ? Possibly the IGBTs in the power modules are different ?

It seems like most of the conversion options listed above discriminate between the Base/Sport (for example the AEM EV option states "The Base unit is supported, and the Sport version will be supported soon", even though that kit replaces the ICB, implying something else inside is also different, but if it was only the IGBTs, you would still think their kit could control either motor).

Also, pre-converted LDU purchase options usually list different power levels available. For example, Stealth EV sells 3 power levels of converted LDUs: Base, Performance, Ludicrous. 057 Tech has 3 similar levels: Base, Sport, Sport Plus.

So I guess there are 2 questions here:
1) What exactly is the difference between the Base and Sport LDUs ?
2) Why are there often 3 power levels/versions of converted LDUs sold by these companies, instead of 2 to match the LDU versions ?

I apologise if this has been covered elsewhere, but I couldn't find anything specific/definitive. Thanks for your advice.
 

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1) The inverter has higher current transistors in the Sport. Not sure if Ludicrous has yet another inverter design.

In any case (pun intended), the battery has to be able to deliver those power levels - it's not merely the LDU that governs.
 

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Discussion Starter · #5 ·
I would assume a dragster would be more like 10 seconds rather than minutes. I wouldn't use an LDU for that.

From what I gather, the LDU is good for ~40kW continuous. Maybe a little more with increased oiling/cooling. Sounds like it's possible to run up to 475kW peak. And many have run in race conditions for ~10 minute durations. Hillclimbs and sprints, for example.

35kWh will give me acceptable range for a small vehicle driven sensibly on the street.

So that's my target: a road car that I can drive to work, and race in some local hillclimb and sprint events.
 

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2 volt packs in parallel. tried and true, or some Pacifica hybrid cells.

mechanically the same, higher rated fets

the ldu may have a higher peak out out, but model 3 drive units have higher continuous ratting.

if you separate the motor and inverter coolant loops and run them in parallel, instead of in series, should be able to push a bit higher.

from my understanding the openinverter based replacement boards are the only way to "over clock" the inverter. but i may be wrong here, where as the can based controls may enable pushing past the rated specs
 

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Discussion Starter · #10 · (Edited)
I haven't seen any specific data regardingthe M3DU vs the MS LDU. I believe tiger82 changed over from an MS LDU to a M3 DU in their race car to improve average power output over a race duration, but I can't find any reference to the actual delta. In my understanding, the LDU is better up to a certain duration, after which the improved efficiency of the M3DU is a better option. It would be intersting to know what that point is for his car. Sounds like a race duration is about 20 minutes, so one might assume the LDU is better for up to about 10 minutes, and the M3DU is better for the full duration. Ballpark figures.

If you read this tiger82, care to clarify the delta for your car ? Thanks.

I thought everybody might be interested in an update. This YouTube video summarizes our last 4 years of development and our move to a Tesla Model 3 drive unit and battery pack.
 

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Discussion Starter · #12 · (Edited)
Yes, that is my understanding too.

However the LDU rotor has no magnets, so has a higher temperature limit. The M3DU rotor does have magnets (in my understanding), which have a much lower temperature limit. Or is that just the front drive unit? Not sure.
 

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@serious_sam,
Did you happen to find any further information?

When I've tried reaching out to Stealth EV inquiring about their listing of the "Ludacris" drive via email, FB and Instagram they've never replied.

I'm assuming that their "Ludacris" isn't the S Plaid based on the Plymouth Hyperlite having purchased his through them and it's clearly not the Plaid drive unit

Which then still has me questioning which drive unit it actually is.
 

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Yes, that is my understanding too.

However the LDU rotor has no magnets, so has a higher temperature limit. The M3DU rotor does have magnets (in my understanding), which have a much lower temperature limit. Or is that just the front drive unit? Not sure.
The Model 3 rear drive unit (like the Plaid and various other current Model S and X applications) has a permanent magnet motor.
The original Model S and X drive units (including those generally called "Large Drive Unit" and "Small Drive Unit"), as well as the front drive unit of the Model 3 and Y AWDs, have induction motors. While they are all induction, the designs of the old (Model S and X) and new (Model 3 and Y) induction motors are different (e.g. aluminum versus copper conductors).

It is true that an induction rotor should be able to handle a higher temperature than a permanent magnet rotor; however, for the same output power level, an induction rotor will generate much more heat (due to resistive heating of the rotor's conductors) than a permanent magnet rotor.
 
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