MoTeC MDC Mitsubishi Lancer Evolution VII/VIII/IX/X Center Diff Controller

Most modern four wheel drive cars use a differential to control the distribution of engine torque between the front and the rear wheels. This centre differential has a significant impact on the handling of a 4WD car on different surfaces and individual drivers will have different preferences for how it is set up.

With the introduction of computer-controlled centre differentials and aftermarket electronics it is now possible to customise these handling characteristics. MoTeC supplies a range of centre differential controllers that can be configured to control the torque distribution by adjusting the percentage lock between front and rear differential.

Rally drivers and their teams can adjust the car's setup for various track surfaces and conditions and specific driver requirements. For example, reducing lock will improve turn-in, while increasing lock can promote understeer on both corner entry and exit and improve braking stability on loose surfaces. Naturally, the setup of the differential controller will also influence traction.

MoTeC's SDC (Subaru Diff Controller) and MDC (Mitsubishi Diff Controller) were designed with the current Group N favourites in mind; the 2003–2007 Subaru STi Impreza and the Mitsubishi Evo VII–X. The SDC and MDC units quickly and easily replace the factory centre differential controllers with no wiring modifications needed.

MoTeC’s Mitsubishi Diff Controllers (MDC and MDC2) are suitable for Mitsubishi Lancer Evo models. They replace the factory fitted Active Centre Diff (ACD) controller as a bolt-in replacement making use of the factory mounting points under the dashboard. The MDCs can be used in vehicles fitted with the ACD/AYC (Active Yaw Control), but the AYC will be disabled.

It is worth considering the installation of a MoTeC M800 Plug-In ECU in addition to the MDC to take advantage of several additional features. Using the RS232 serial communication link, all values from sensors connected to the MDC can be logged in the M800 Plug-In ECU without having to duplicate any of the sensors.

Functionality

The MDC is used to adjust the torque split between the front and rear differentials to achieve greater control over handling characteristics such as traction, braking on loose surfaces, turn-in response, and understeer on both corner entry and exit.

The centre differential is essentially a limited slip differential with adjustable preload. The preload is proportional to the fluid pressure in the centre differential. The MDC works by regulating solenoid current, which in turn, controls the fluid pressure. When no pressure is applied (0% lock) the centre differential operates as an 'open diff'. With increasing fluid pressure (increasing percentage lock) the preload increases, requiring more torque difference between front and rear wheels before the centre differential will slip.

There are six selectable control modes: 0% lock, 100% lock and four user-configurable modes. These modes can be cycled through using the factory dash mounted ACD button.