How We Do It

ENGINEERING AND DESIGN

The first step of this build was to determine if the transmission was going to stay. Since the goal is to make this vehicle easier to drive, it was decided to eliminate the transmission. Without the mechanical advantage of the transmission, a high torque motor is needed. Enter the Tesla rear drive motor with 327 ft-lbs of torque! By mounting the Tesla motor where the original transmission was, a huge space under the hood (more appropriately, the bonnet) is created.

With the poor drag coefficient of this vehicle, a large battery pack is required to achieve desired range. Therefore a 55 kw-hr battery pack was selected which can deliver the 350Vdc volts that the Tesla motor requires and should provide 150-175 mile range.

DESIGN VALIDATION / PROTYPING

With the internal combustion engine, fuel tank, exhaust system, cooling system, etc. removed, a mock-up installation of the Tesla motor was done. This mock-up set the motor height for the front driveshaft to clear the forward frame cross-member. In addition, it revealed that the seat box and center floor tunnel sheet metal requires modification.

Mock up installation of the battery pack did not reveal any surprises since the Fellten Universal battery pack was sized to fit into Land Rover Series and Defender models.

ENGINEERING PROCESS: EARLY CONFIGURATION

At NomXd Motors, we start by identifying a motor which will match (or slightly exceed) the original gas engine’s output torque. On this build a Tesla Model S rear drive motor was selected to provide ample torque for all driving conditions.

The output of this Tesla motor is capable of delivering almost 6 times more torque to the rear drive wheel! Therefore, the Tesla motor gear ratios need to be changed to reduce the torque output to about twice the original engine’s output.

Since the customer wanted to keep power brakes, a vacuum pump was added to provide vacuum to the brake booster. A vacuum storage canister and pressure switch was also installed so vacuum pump won’t run continuously. In order to provide heat, a 3000 watt heater element will be installed and powered off the traction battery pack.