The Model S large rear Drive unit has a gear reduction ratio of 9.73:1 . I’m contemplating on different installation options of this drive unit as I plan to keep my Mitsubishi Evolution 8 all wheel drive.
Options I’ve been thinking of:
1. Install large rear drive unit as rear axle and add small front drive unit at the front. Dual motor awd. Not 100% sure if large rear drive unit will fit the back. So below are my other secondary plan B or C options.
(EDIT) Option 2 won’t work as I incorrectly calculated multiple ratios . Should be multiplied not added.
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 .
Then I will rotate the motor orientation horizontally so the left axle is facing towards the rear and right axle is facing the front of the car. The drive unit will spin both “rear diff’s” at rear and front of the car. Essentially creating a single Tesla motor awd setup.
3. Again install oem rear differential in the rear and one more in the front of the car. This time completely remove the Tesla transmission and directly connect the motor to the rear diff. I’ll do the same at the front with a second drive unit. But doing this will result in each motors having to spin a ratio of 3.307 : 1 .
Now here is my concerns . As the ratio is reduced the effort the motor will need to propel the car is increased. I don’t want to have a drastic decrease in performance .
Option 3, I will have two motors rated at 700-800 combined awd hp (in oem ratio) but now they will try to spin a ratio of 3.307 : 1 .
What do you guys think about option 3 ? Its mainly the ratio and how much it will effect power output that I’m concerned about . Is the ratio too low to be useful or outside of power curve of the motor(s) . Other issues I missed ? I don’t care about increased top speed, I just don’t want to lose on acceleration 0-60 etc..