2004 Mitsubishi Eclipse Coupe Technical highlights

ENGINE

Three engines are available for the 2004 Mitsubishi Eclipse coupe. All three motors are engineered to deliver smooth power while maintaining good fuel economy and Low Emission Vehicle (LEV) standards.

• 2.4-liter four-cylinder (Engine 4G64)

The Eclipse RS and GS models come equipped with a durable 2.4-liter, SOHC, 16-valve four-cylinder engine. This powerplant is tuned to the sporting characteristics of the Eclipse and provides ample torque for brisk acceleration from a standing start.

The large-displacement 2.4-liter engine allows the Eclipse to produce 147 horsepower at 5500 rpm (142 horsepower with automatic transmission) and an impressive 158 pound-feet of torque at 4000 rpm, minimizing the need to "wind up" the engine as is often required in smaller displacement four-cylinder engines. The 4G64's block is a closed-deck cast-iron design while the cylinder head is cast in aluminum. In keeping with the low-rpm power-producing nature of this motor is its under-square design with an 86.5-mm bore and 100-mm stroke combination.

Features that contribute to the 2.4-liter engine's responsiveness include optimized valve timing and a high-velocity runner intake manifold with a cold-air induction system. Drawing air from above the radiator rather than from inside the hot engine compartment, the cold-air induction system allows a cooler, denser charge of air/fuel mixture to be fed to the cylinders. This combination produces a more complete and powerful combustion. The intake manifold runners are tuned for mid-range punch and contoured to increase airflow at both low and high engine speeds.

The 2.4-liter motor's camshaft profiles are designed to provide more lift and duration, enhancing the engine's combustion efficiency. The 2.4-liter unit produces low-rev horsepower and torque for a quick off-the-line feel and swift highway passing power.

Counter-rotating balance shafts quell the low-speed rumble and high-rpm tremble inherent in large, powerful four-cylinder engines. An induction-hardened steel crankshaft-secured to the block by twice the usual number of main bolts-insures stability for the reciprocating assembly. Thanks to a liquid-filled engine mount that isolates the engine from the chassis, the Eclipse provides a refined driving experience rarely achieved in a four-cylinder car.

• 3.0-liter V6 (Engine 6G72)

The 2004 Eclipse GT features a 3.0-liter, SOHC, 24-valve V6 engine that produces 200 horsepower at 5500 rpm and 205 pound-feet of torque at 4000 rpm. The cast-iron block with aluminum head V6 delivers linear power throughout its rev range for quick, smooth and consistent acceleration. This compact V6 is also designed to generate very low levels of noise, vibration and harshness thanks to its 60-degree architecture and large-bore, short-stroke design.

Like the four-cylinder engine, the V6 uses a cold-air induction system to feed the cylinders. In addition, a low-restriction exhaust system adds power and a sports car exhaust note to the rousing performance of Mitsubishi's top sports coupe.

Designed to let the engine exhale more easily, the system is tuned to eliminate the booming sounds that often accompany a high-performance exhaust. Although a 60-degree V6 is inherently smooth running, a crankshaft girdle, structurally-supportive aluminum oil pan and aluminum engine support bracket all contribute to greater refinement and outstanding durability.

• 3.0-liter V6 with Variable Induction

The Eclipse GTS is powered by a 3.0-liter, SOHC, 24-valve V6 engine that is designed to deliver superior power and responsiveness. This engine develops 210 horsepower at 5750 rpm, and a peak torque of 205 pound-feet at 4000 rpm. The increase in power can be attributed to a higher 10.0:1 compression ratio, and a variable-length intake runner induction system called Mitsubishi Variable Induction Management (MVIM) that optimizes the intake runner length for a given rpm. The length of the intake runner relative to engine speed promotes superior mixture quality and velocity for optimum combustion. The internal architecture of this motor is the same as the V6 under the hood of the Eclipse GT coupe and features 91-mm bore and a 76-mm stroke.

TRANSMISSION

The Eclipse offers three different transmissions to complement the power and engineering behind the engines.

• Five-Speed Manual

A five-speed manual transmission is available on RS, GS, GT and GTS models, enabling the driver to maintain exceptional control over power delivery. Double-cone synchronizers on first gear and triple-cone synchronizers on second gear help to ensure smooth gear transfers and ease of use. The V6 model also adds a double-cone synchronizer on third gear. A keyless synchronizer design is used for smooth operation. Reverse gear also is fitted with dual-cone synchronizers for easy gear engagement to eliminate gear grinding and help improve reliability. The GTS model is outfitted with a 4.01:1 final drive ratio for improved acceleration through the gears with the five-speed.

The transmission shifter features a fulcrum-action lever that reduces the range of motion needed to select a gear, providing a more positive feel.

• Four-Speed Automatic

All Eclipse editions are available with a four-speed automatic transmission featuring Mitsubishi's Adaptive Shift Control. With the gear selector in Drive, the transmission relies on "learned control" to tailor shifts to the driver's style. For a relaxed driving style, the transmission will shift at lower engine speeds for smooth and quiet operation and improved fuel economy. During more spirited driving, the transmission will shift at higher engine speeds, improving responsiveness and acceleration.

The automatic transmission remains in constant communication with the engine so that power output is momentarily reduced during shifts. This quick, momentary reduction in power provides a much smoother gear change under normal driving conditions, while reducing shift shock during hard acceleration.

Additionally, the transmission will downshift for engine braking if the computer senses that the driver brakes frequently while descending a hill. The transmission also will hold a lower gear while climbing hills for more power and to prevent constant upshifting and downshifting.

• Four-Speed Automatic with Sportronic(TM) Sequential Shifter

The Eclipse GS, GT, and GTS models fitted with automatic transmissions are equipped with the Mitsubishi Sportronic(TM) Sequential Shifter, which enables the driver to manually control gear selection. By simply moving the shift selector forward or backward in the Sportronic(TM) gate, the transmission will upshift or downshift at the driver's command. In Sportronic(TM) mode, the transmission shifts faster and more firmly than in the automatic mode, for extra-quick gear selection. The GTS option features numerically higher final drive ratios of 4.01:1 with the automatic transmission option for improved acceleration.

Unlike the systems in some other manufacturer's cars, Sportronic(TM) will remain in the selected gear all the way to redline without allowing the transmission to upshift. If the driver does not upshift and the transmission reaches the rpm redline, fuel cutoff will intervene but the transmission will remain in the selected gear. Sportronic(TM) is programmed to override the driver's command in one circumstance: if the gearbox is not downshifted to first gear upon stopping the vehicle, the transmission will automatically select first gear.

Double downshifts also are possible, but the transmission's electronic controls will not allow a downshift that over-revs the engine. In slippery conditions, the transmission can be manually shifted into second gear at rest for a more gradual takeoff. Unlike a manual transmission, the driver does not have to lift off the gas when changing gears, allowing for a sporty, uninterrupted succession of shifts.

SUSPENSION

The Eclipse is designed for exceptional performance in three primary areas: ride quality, handling response and straight-line stability.

The Eclipse incorporates large-diameter MacPherson struts in front with offset placement of the front springs relative to the dampers. This design reduces friction in the suspension and diffuses road shock from rough pavement. The lower A-arms are attached to a die-cast aluminum crossmember in V6 models and a steel crossmember with a longitudinal support stay in four-cylinder models. Because of the highly rigid mounting frame, the front suspension and steering gear no longer have to take up the slack created by chassis flex. GT trim lines have the added benefit of a front strut tower brace that further stiffens the chassis. As a result, reflexes are sharp and steering response is direct with a communicative feel.

The Eclipse's roll center is set low to aid in cornering stability. This feature helps the front tires stay perpendicular to the road as the suspension moves up and down through the stroke and rebound. It yields more road contact through varying road conditions and provides better traction and handling. The front stabilizer bar controls body lean by using pillow-ball links that reduce the compression effects of rubber bushings. By pressing a ball joint into a solid housing, the link pivots but does not compress under load. The three-quarter-inch thick rear stabilizer bar found under the GT and GTS trim lines further improves handling.

At the rear, the Eclipse features an independent, multi-link suspension with rigid crossmember mounting points. Additionally, the upper and lower control arms are made from stiff, strong, welded tubular steel, rather than the more common stamped steel. A rubber stop on the bushing (located at the forward end of the trailing link where it connects to the body) is designed to prevent excess lateral motion of the control arm and helps stabilize suspension movement.

STEERING

For quick response and performance, the Eclipse incorporates a variable-assist power rack-and-pinion steering system with a valve and gear design that provides linear transitions between low and high assist levels. In low-speed situations, the hydraulic assist is increased to make parking and urban driving easier, but as the engine and vehicle speed increase, the system gradually reduces assist to give the driver a better feel for the road and a greater sense of control.

BRAKES, WHEELS & TIRES

All Eclipse trim lines use a tandem brake booster and high-rigidity front-hub assemblies for consistent power assist and precise modulation of braking force. RS and GS trim lines feature 10.1-inch ventilated discs up front, while the GT increases to a 10.9-inch diameter for added stopping performance. In the rear, RS and GS feature 9.0-inch drum brakes, while GT and GTS both are equipped with 10.3-inch solid discs. A three-channel, four-wheel anti-lock braking system (ABS) is also standard on the GTS.

The 195/65HR15 tires on the RS, 205/55HR16 tires on the GS and 215/50VR17 tires on the GT and GTS give the Eclipse an outstanding hold of the road. All models have aluminum alloy wheels.

SAFETY

As with other models, the Eclipse is fitted with a total package of safety features designed to help enhance the safety of passengers if a collision occurs.

Mitsubishi Motors' engineers use the acronym RISE-Refined Impact Safety Evolution-as a description of their goal to take safety to a higher level. This includes a number of elements such as high-rigidity side members, roof reinforcement, large-section side sills, door frames and side-guard door beams to create a tough skeletal structure around the interior. This design helps to improve safety in offset crashes and side impacts. In addition, front and rear crumple zones help absorb impact energy to keep the force of a crash away from occupants.

For additional driving security, the GTS trim line comes with a three-channel anti-lock braking system (ABS) that helps to enhance steering control during hard braking. Electronic slip sensors send signals to the ABS computer, apportioning braking power to the appropriate wheels.

Traction control is included on Eclipse GTS when equipped with the optional Sportronic(TM) transmission. The system will activate the front brake calipers to slow a spinning wheel. On low-traction surfaces, the braking of one wheel will automatically transfer power to the opposite wheel, helping the car to pull away from a stop.

The Eclipse is equipped with a driver's and front passenger's airbag inflatable Supplemental Restraint System (SRS). In addition, dual front side-impact airbags are available as part of the GTS trim level. Side airbags are designed to help reduce head and thorax injuries in the event of side impacts.

WARRANTY

The Eclipse is backed by a comprehensive New Vehicle Limited warranty from Mitsubishi Motors that covers the vehicle from bumper-to-bumper for three years or 36,000 miles. In addition, the powertrain is covered by a five-year or 60,000 mile limited warranty, while body panels have a seven-year or 100,000 mile anti-corrosion/perforation limited warranty. The warranty service also includes 24-hour emergency roadside assistance with free towing to the nearest authorized Mitsubishi retailer for warranty-related repairs for three years or 36,000 miles. Mitsubishi will also aid with hotel and rental car arrangements and in contacting family members.

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