[kennybobby]

You got me curious, how would you change the gear ratio of the tesla inverter/motor/gearbox/differential?

How would you control the motor if you separated it from the inverter and gearbox? What about routing for the coolant ports. How would you couple the motor shaft? The motor "wiring" is internal to the drivetrain, the external wiring runs to the inverter.

What are you planning to use for a battery pack? The battery pack is one of the primary factors that determines how fast you can accelerate (voltage, current capacity, weight).

 

[4G63T]

You got me curious, how would you change the gear ratio of the tesla inverter/motor/gearbox/differential?

How would you control the motor if you separated it from the inverter and gearbox? What about routing for the coolant ports. How would you couple the motor shaft? The motor "wiring" is internal to the drivetrain, the external wiring runs to the inverter.

What are you planning to use for a battery pack? The battery pack is one of the primary factors that determines how fast you can accelerate (voltage, current capacity, weight).

ZeroEV sells reduction gears to 4.5:1 . Check out this clip .
https://m.youtube.com/watch?v=_GigD0s47RI

For option 2 , I would separate and install it elsewhere. I play to source a broken Gear case of the inverter side. Install the inverter there, modify the casing to connect coolant feed and return lines . And regarding the 3 Inverter leads/connectors/terminals , I would just run extended wiring to the motor.

As for the Cooling of the other half where the motor and trans are, I would modify the inverter ports on the case so the coolant flow continued back to area that cools the gears and return.

For option 3, I would separate the inverter but keep attached to that half of the case. Again modify the fluid ports and use the same 3 inverter to motor leads but with extended wires.

Coupling the motor Option 3 : After watching videos of disassembly and removal of the gears, I believe I can get/have made couplers to fit the motor splines and U joint on the other end to bolt to the rear differential .

Haven’t decided battery pack yet . Leaning towards LG chem. Range is not as important as power, 70 miles would be awesome but it might be less at 40 miles, I can live with that.

 

[electro wrks]

2. Keep oem rear differential with 3.307 ratio and mount another rear differential at the front of the car. I will install a gear reduction 4.5:1 inside the Tesla drive unit. This would give me a total ratio of 7.807:1 .

For the 4.5:1 Tesla ratio change for option 2 are you referring to something like these Quaife supplied parts?: https://www.youtube.com/watch?v=_GigD0s47RI Last I heard, Quaife was having durability problems with this gear set. Does anyone know if this has been resolved?
Also, when you calculate the overall ratio of gear boxes or gear trains in series, you don't add the separate ratios, you multiply them. 4.5:1 Quaife set-up Tesla X 3.307:1 stock axle ratio = ~14.88:1 overall ratio.

 

[4G63T]

2. Keep oem rear differential with 3.307 ratio and mount another rear differential at the front of the car. I will install a gear reduction 4.5:1 inside the Tesla drive unit. This would give me a total ratio of 7.807:1 .

For the 4.5:1 Tesla ratio change for option 2 are you referring to something like these Quaife supplied parts?: https://www.youtube.com/watch?v=_GigD0s47RI Last I heard, Quaife was having durability problems with this gear set. Does anyone know if this has been resolved?
Also, when you calculate the overall ratio of gear boxes or gear trains in series, you don't add the separate ratios, you multiply them. 4.5:1 Quaife set-up Tesla X 3.307:1 stock axle ratio = ~14.88:1 overall ratio.

Your right overall ratio is calculated by multiplying . I was wrong.

I don’t think there are differential ratios of 2:1 and doing something custom to accomplish that is out of my capabilities . So option 2 won’t work.


I guess then I just need to know is 3.307 ratio too “tall” for each motor ? Tesla designed the drive unit to have 9.X:1 ratio for a ~4800 lbs car. I estimate mine to be around 3300 lbs. Perhaps the power curve of the motor will still allow it to be adequate for tall ratio?

 

[remy_martian]

Option 4. Ditch the idea of using a Tesla drive unit

 

[4G63T]

Option 4. Ditch the idea of using a Tesla drive unit

So then what do you recommend to use ?

 

[ev-swap]

Hi 4G63T,

I think its a great idea to keep your evo 8 all wheel drive! And in my opinion, Tesla drive units are the way to go. With over 500,000 Model 3's produced so far, the junk yards of the world are going to fill up with these modern ev drives. And Damien Maguire is so close to cracking the code on these newer drives, its just a matter of time before they become the defacto standard.

So, back to your design. There is a guy named Sam that converted his AWD Audi by splitting a Tesla Large Drive unit (like you propose), putting in a gear reducer to make it more like an ICE (rpm wise) and putting the electric motor where the engine was; connecting it directly to the front transaxle.

Its a slick build. With a lot of custom fabrication (especially since he indicates that he built the reducer from scratch).

https://www.youtube.com/watch?v=IOYY_AlRWQA

Go for it!