Press Release
Engine
The well-proven 2-liter in-line 4-cylinder 16-valve DOHC intercooler-turbocharged 4G63 engine has undergone detail improvements. The power unit retains Lancer Evolution's trademark flat torque band that kicks in from low engine speeds but now generates gutsier torque in the mid- to high-rev band.*
The turbocharger uses a larger turbine nozzle with matching cam profile to deliver higher output at mid- to high engine speeds.*
The turbocharger waste gate now uses two solenoids. This optimizes boost pressure control to give more stable torque in the low to mid-range and helps the powerplant to generate class-topping torque of 40.8kg-m (400N-m) at 3,500 rpm.*
Durability is improved through shape optimization and reinforcement of the cooling water channels, uprating from a 3-ply to 5-ply head gasket and the use of magnetic ion-coated piston rings.
Engine response is improved with the use of lighter silent shafts.
Cooling performance is improved with the use of a larger oil cooler that features two extra rows.
(* RS 5M/T excluded)
Body
Evolution VIII MR is the first steel monocoque body Japanese production car to use an aluminum roof panel, reducing vehicle weight by some 4 kg. Reduction of weight in the upper body lowers the vehicle's center of gravity and reduces roll moment to realize a substantial improvement in handling performance.
To join the steel monocoque frame and aluminum roof panel, Evolution VIII MR employs an innovative method that uses self-piercing rivets, which expand radially into the steel of the structural member below, and a structural adhesive.
The provision of a single longitudinal design bead in the roof panel solves the problem of thermal warping that occurs in the manufacturing process as a result of aluminum having a thermal expansion coefficient nearly twice that of steel. This measure has also enabled any increase in the weight of the roof panel to be minimized.
For increased cabin strength, diagonal braces are used to reinforce the roof joins at the front, center and rear pillars.
The front door side impact bars use aluminum instead of steel, reducing weight by 3.5 kg while providing the same level of impact safety.
Suspension
Shock absorbers jointly developed with Bilstein exclusively for Evolution VIII MR offer superior response characteristics and realize better road holding.
The use of different damping rates for the single-tube front and rear shocks and shape optimization of the rear bump stop has resulted in superior levels of handling stability and road holding together with a sporty ride quality.
Electronically-controlled 4WD system
Harmonized control of the ACD2, Super AYC3 and Sport ABS4 4WD system components is more finely tuned on Evolution VIII MR after feedback from testing programs and from use in actual competition. As a result, the all-wheel control (AWC) system is tuned with greater bias on sporty and competitive use.
On Evolution VIII, the AWC system gave control bias to the Sport ABS in order to stabilize the body attitude under hard braking. For Evolution VIII MR, the system is tuned for optimum response on different road surfaces. More specifically, by keeping ACD + Super AYC control active while Sport ABS is in operation, the car now responds more accurately to steering inputs as it enters, and holds its line better through, corners on dry tarmac and other high-friction surfaces.
The weight of the Super AYC unit has been reduced by 800 grams by switching from steel to aluminum for the clutch case and by reviewing the metal clutch disc gauge. The use of high-strength steel for the differential hypoid gears has raised fatigue strength by some 20%.
- Mitsubishi Racing: a designation first used on the Colt Galant GTO, the first Mitsubishi production car powered by a DOHC engine, and traditionally reserved for the Lancer, GTO and other Mitsubishi high-performance sports models.
- The Active Center Differential incorporates an electronically controlled hydraulic multi-plate clutch. An ECU optimizes clutch cover clamp load for different driving conditions, regulating the differential limiting action between free (where torque is split equally between front and rear wheels) to locked states. The result is improved steering response together with better traction. ACD operation switches automatically between three modes - Tarmac / Gravel / Snow - to realize quicker control response for changes in road surface.
A single ECU provides integrated management of both ACD and Super AYC components.
- The Active Yaw Control system uses a torque-transfer mechanism in the rear differential. Under ECU control, the system operates to raise cornering performance by transferring torque between the rear wheels as dictated by driving conditions and so control the yaw moment acting on the car body. With Super AYC, the use of a bevel- instead of a planetary-gear differential enables the transfer of almost twice as much the torque between the rear wheels. As well as reducing understeer further, Super AYC acts like a limited slip differential to extend cornering limits. The use of a single ECU to integrally manage Super AYC with the ACD produces a synergism that makes both components operate more effectively than if they were under independent control.
- The Sport Anti-lock Braking System ECU uses information from a steering angle sensor that detects steering inputs as well as from lateral G and vehicle speed sensors to apportion pressure to each of the four wheels independently. The result is improved steering response under braking. Integral with Sport ABS, MMC's Electronic Brake Force Distribution (EBD) system optimizes allocation of braking force between the front and rear wheels. Increasing the pressure applied to the rear wheels when braking close to the limit, EBD reduces the load acting on the front wheels to realize better anti-fade performance. The system also compensates for changes in surface and vehicle load conditions to ensure predictable and consistent stopping performance at all times.
Text & photos courtesy Mitsubishi Motors Corp.
