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silver05bullet · 12-28-2005, 12:27 PM

ACTIVE CENTER DIFFERENTIAL (Doesnt split the torque its always 50/50)

First employed on the Japanese-market Evolution VII, Mitsubishi’s Active Center Differential (ACD) made its North American debut in Lancer Evolution VIII MR, and is standard equipment on all Lancer Evolutions. Combined with a front helical limited slip differential, the ACD helps raise the Evo’s dynamic handling performance to a new level.

The ACD uses a center differential to split torque up to 50:50 between the front and rear wheels using an electronically controlled hydraulic multi-plate clutch. An ECU optimizes clutch cover clamp load for different driving conditions, regulating the differential limiting action between a free state (where torque is split equally between front and rear wheels) and locked states according to driving conditions. The result is better steering response and better traction. From a switch on the dash, the driver may select between three ACD modes – Tarmac, Gravel, and Snow – for response to changes in road surfaces.

The ACD computer receives data from various sensors to calculate the limited-slip torque suitable for a variety of conditions. For instance, steering wheel angle, throttle opening, wheel speeds, and longitudinal and lateral movements of the vehicle are constantly measured to determine the vehicle’s path of travel, which helps to determine whether limited-slip torque should increase or decrease at any given time.

The viscous coupling unit (VCU) limited-slip mechanism from the Lancer Evolution’s center differential has been replaced by a hydraulic multi-plate clutch in the Evolution. The maximum limited-slip torque of the multi-plate clutch is about three times that of a conventional VCU. The hydraulic unit housed in the engine compartment regulates the hydraulic pressure of the multi-plate clutch within the range of 0 to 145 psi.

With the adoption of the ACD, the front differential is changed from an open differential to a helical limited-slip differential. The helical-type limited slip differential provides better durability and higher performance when it’s needed most – while steering. Unlike an open differential, which shifts power to the wheel with less grip, the helical limited-slip constantly shifts the bias toward the wheel that has more traction.
Under straight-line acceleration, power remains evenly split between the front wheels. While cornering (e.g., accelerating out of a turn), the helical LSD directs power away from the inside wheel and toward the outside wheel, allowing the driver to begin accelerating earlier and exit the turn at a higher speed, without losing traction.
All Lancer Evolution models use a reliable, mechanical, plate-style, 1.5-way limited slip differential at the rear. This unit’s effective design has proven itself in competition providing traction and durability.

To complete this the turbo EVO 9's improved and the MIVEC provides on average an additional 30-40 hp stock over the EVO 8

Cosmetic diffrences: The front fascia was redesigned, the rear bumper was also changed on the JDM version of the EVO IX but not brought to the US because of crash safety standards, the wheels shave of about 1.5lbs out of the evo there was a misprint in the evo 9 brocure that could be read that each wheel save 1.5 lbs, its incorrect all 4 save about 1.5 lbs

EVO 8:

EVO 9:

All of the evos shine with a catless turbo back exhaust, boost controller, intake and a tune, as previously stated while those mods at 21-22psi will yield approximately 320hp out of the EVO VIII, the EVO IX's with just these mods are yielding upwards of 350hp, just because of the slight improvements and mivec especially, and evo 8 will need cams to achieve similar numbers as the 9. The only drawback there is no cams available for the evo 9 at this time.

Any questions post them up ill try to find out and post answers for you

Thanks,
Silver05Bullet

12-28-2005, 12:27 PM	#2
silver05bullet Tri-State Addict Join Date: Nov 2005 Location: Jerzey Son Member #1084 iTrader: (0)	ACTIVE CENTER DIFFERENTIAL (Doesnt split the torque its always 50/50) First employed on the Japanese-market Evolution VII, Mitsubishi’s Active Center Differential (ACD) made its North American debut in Lancer Evolution VIII MR, and is standard equipment on all Lancer Evolutions. Combined with a front helical limited slip differential, the ACD helps raise the Evo’s dynamic handling performance to a new level. The ACD uses a center differential to split torque up to 50:50 between the front and rear wheels using an electronically controlled hydraulic multi-plate clutch. An ECU optimizes clutch cover clamp load for different driving conditions, regulating the differential limiting action between a free state (where torque is split equally between front and rear wheels) and locked states according to driving conditions. The result is better steering response and better traction. From a switch on the dash, the driver may select between three ACD modes – Tarmac, Gravel, and Snow – for response to changes in road surfaces. The ACD computer receives data from various sensors to calculate the limited-slip torque suitable for a variety of conditions. For instance, steering wheel angle, throttle opening, wheel speeds, and longitudinal and lateral movements of the vehicle are constantly measured to determine the vehicle’s path of travel, which helps to determine whether limited-slip torque should increase or decrease at any given time. The viscous coupling unit (VCU) limited-slip mechanism from the Lancer Evolution’s center differential has been replaced by a hydraulic multi-plate clutch in the Evolution. The maximum limited-slip torque of the multi-plate clutch is about three times that of a conventional VCU. The hydraulic unit housed in the engine compartment regulates the hydraulic pressure of the multi-plate clutch within the range of 0 to 145 psi. With the adoption of the ACD, the front differential is changed from an open differential to a helical limited-slip differential. The helical-type limited slip differential provides better durability and higher performance when it’s needed most – while steering. Unlike an open differential, which shifts power to the wheel with less grip, the helical limited-slip constantly shifts the bias toward the wheel that has more traction. Under straight-line acceleration, power remains evenly split between the front wheels. While cornering (e.g., accelerating out of a turn), the helical LSD directs power away from the inside wheel and toward the outside wheel, allowing the driver to begin accelerating earlier and exit the turn at a higher speed, without losing traction. All Lancer Evolution models use a reliable, mechanical, plate-style, 1.5-way limited slip differential at the rear. This unit’s effective design has proven itself in competition providing traction and durability. To complete this the turbo EVO 9's improved and the MIVEC provides on average an additional 30-40 hp stock over the EVO 8 Cosmetic diffrences: The front fascia was redesigned, the rear bumper was also changed on the JDM version of the EVO IX but not brought to the US because of crash safety standards, the wheels shave of about 1.5lbs out of the evo there was a misprint in the evo 9 brocure that could be read that each wheel save 1.5 lbs, its incorrect all 4 save about 1.5 lbs EVO 8: EVO 9: All of the evos shine with a catless turbo back exhaust, boost controller, intake and a tune, as previously stated while those mods at 21-22psi will yield approximately 320hp out of the EVO VIII, the EVO IX's with just these mods are yielding upwards of 350hp, just because of the slight improvements and mivec especially, and evo 8 will need cams to achieve similar numbers as the 9. The only drawback there is no cams available for the evo 9 at this time. Any questions post them up ill try to find out and post answers for you Thanks, Silver05Bullet __________________ 666 To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures. Last edited by silver05bullet; 12-28-2005 at 01:01 PM.