2004 Mitsubishi Eclipse Spyder technical highlights

ENGINE

The combination of bold styling, responsive power and exciting performance made the Mitsubishi Eclipse Spyder convertible an immediate success upon its introduction three years ago. The Eclipse Spyder offers two engine options: a powerful 2.4-liter four cylinder and a spirited 3.0-liter V6. Each of the Spyder's engines is designed to deliver superior torque while maintaining good fuel economy and meeting Low Emission Vehicle (LEV) standards.

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

The Eclipse Spyder GS shares the responsive 2.4-liter, SOHC, 16-valve four-cylinder engine with its Coupe sibling. This powerplant is tuned to the sporting characteristics of the Spyder and provides ample torque for brisk acceleration from a standing start.

The large-for-a-four-cylinder 2.4-liter in-line engine found in the Spyder GS produces 147 horsepower at 5500 rpm (140 horsepower when mated to the automatic transmission) and an impressive 158 pound-feet of torque at 4000 rpm (155 pound-feet with the automatic transmission). The large displacement and low-speed torque capabilities of the 4G64 minimize this engine's need for high rpm to make power as required in smaller displacement four-cylinder engines.

Features that contribute to the 2.4-liter engine's responsiveness include torque-savvy cam profiles and an isometric intake manifold with 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 to be fed to the cylinders.

This cooler, denser air charge helps produce more complete combustion of the fuel mixture and better power. The intake manifold runners are tuned for maximum mid-range response, yet contoured for effectiveness at both low engine speeds and wide open throttle conditions. The aggressive camshaft profile, with increased valve lift and duration, enhances the engine's ability to "inhale" the fuel mixture and "exhale" spent fumes efficiently. These features combine to produce ready horsepower and torque for a quick off-the-line feel and impressive highway passing power.

Counter-rotating balance shafts quell the low-speed rumble and high-rpm tremble common to large, powerful four-cylinder engines. An induction-hardened steel crankshaft-secured to the block by twice the usual number of bolts-makes the engine strong and helps to minimize vibration. Coupled with a liquid-filled engine mount that isolates the engine from the chassis, the Eclipse Spyder provides a refined and comfortable driving experience rarely achieved in a four-cylinder.

• 3.0-liter V6 with Mitsubishi Variable Induction Management System (6G72 Engine with MVIM)

The 2004 Eclipse Spyder GT and GTS features a 3.0-liter, SOHC, 24-valve V6 engine with Mitsubishi's Variable Induction Management system (MVIM) that produces 210 horsepower at 5750 rpm and 205 pound-feet of torque at 3750 rpm. This rugged V6 with a cast-iron block and aluminum heads delivers linear power throughout its rev range for quick acceleration.

The power increase over the base V6 found in the GT Coupe is the result of higher compression (10.0:1) and a flexible, higher flowing induction system. The variable intake system varies intake runner length according to a given engine rpm. Thus, the engine achieves optimum intake tuning across its entire rev-band for superior responsiveness and ultimate power from 0 to redline. A refined six-cylinder, this 6G72 is designed to generate very low levels of noise, vibration and harshness due to its 60-degree Vee architecture and its large-bore and 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 rousing performance.

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

TRANSMISSION

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

• Five-Speed Manual

A five-speed manual transmission is standard equipment on GS, GT and GTS enabling drivers to take control of Spyder's power. Double-cone synchronizers on first gear and triple-cone synchronizers on second gear ensure smooth gear transfers and ease of use. The V6 model adds a double-cone synchronizer on third gear. The synchronizers use a keyless design for smooth operation.

The reverse gear also is fitted with dual-cone synchronizers to eliminate possible grinding when engaging reverse. This transmission's gear spacing is designed to maximize the engine's power, keeping the revs floating near the torque-curve's "sweet spot." In addition, the final drive ratios of the Spyder GT and GTS are numerically higher to improve off-the-line acceleration.

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

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

The Spyder GS, GT, and GTS also offer the flexibility of an optional automatic transmission with Mitsubishi's Sportronic(TM) Sequential Shifter, allowing the driver to manually control gear selection. By moving the shift level into the Sportronic(TM) gate and toggling the shifter forward or backward, the transmission will upshift or downshift, stepping one gear at a time, sequentially, at the driver's command. In Sportronic(TM) mode, the transmission shifts faster, with greater urgency than in basic automatic mode, making for more exhilarating driving while maintaining its pure automatic capability for hassle-free crawls through traffic.

Unlike some manufacturers' systems, 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, the fuel cutoff will intervene but the transmission remains 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, drivers don't have to lift off the gas when changing gears, allowing for uninterrupted shifts.

SUSPENSION

The Eclipse Spyder is designed for exceptional performance in three primary areas: ride quality, handling response and straight-line stability. Each represents a significant step forward in the comfort, cornering and long-distance cruising ability of Mitsubishi's open-top convertible.

The Eclipse Spyder 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 reinforced, die-cast aluminum crossmember in V6 models and a steel crossmember with a longitudinal support stay in four-cylinder models. Thanks to the Spyder's highly rigid unibody and subframes, the front suspension and steering gear no longer have to take up the slack created by chassis flex. The GS, GT, and GTS trim levels enjoy 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.

The roll center of the Spyder is set low to aid in cornering stability. This helps the front tires stay perpendicular to the road as the suspension moves up and down through stroke and rebound, yielding more road contact through varying road conditions, thus providing 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 same link is used on the rear stabilizer bar of the Spyder.

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

STEERING

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

BRAKES, WHEELS & TIRES

The Eclipse Spyder GS features 10.1-inch ventilated discs up front, while GT and GTS discs increase to 10.9-inch diameters for added stopping performance. In the rear, GS uses 9.0-inch drum brakes, and GT and GTS models upgrade to 10.3-inch solid rear discs.

The Spyder GS features 205/55R16 tires, while the GT and GTS upgrade to 215/50R17 treads. All three models roll on stylish aluminum alloy wheels.

CHASSIS

Although there is a coupe version of the Eclipse, the Eclipse Spyder was engineered from the beginning to be a convertible, incorporating the benefits of state-of-the-art CAD/CAM engineering. This specially designed, unitized chassis structure is much stronger and more resistant to the body shake and shudder affecting most convertibles.

The unitized chassis also gives the vehicle considerable bending and torsional (twisting) rigidity without producing a significant weight increase. This built-in rigidity is also responsible for the Spyder's superior handling.

The Eclipse Spyder's robust structure starts with a rolled-steel bar that runs behind the dashboard and attaches to the base of the A-pillars with large gussets that are tied into vertical boxed pillars at the front of the door frames. A three-dimensional structure inside the front fenders attaches to the upper front portion of the pillar, while lower side sills attach to the lower rear portion of the pillar and run under the door. Together with a larger B-pillar that runs from the floor to the beltline at the trailing edge of the door frame, and a structural rear inner-fender, these unitized pieces create load-bearing strength across the side of the car.

Cross-cabin reinforcements at the rear of the vehicle include an "upside-down" strut tower brace that runs across the leading edge of the trunk floor to form the bottom portion of the rear bulkhead. Meanwhile, freestanding U-shaped pillars, connected with a corrugated-steel plate, form a second structure behind the rear seat, and a massive high-rigidity floor crossmember runs laterally below the rear seat to connect the B-pillars.

The rolled-steel bar under the dash and a structural front bumper beam complete the lateral strengthening members of the body. A standard front strut tower brace, with additional attachment points at the firewall, and boxed lower rear suspension arms work independently to provide lateral stiffness under high cornering loads.

Throughout the rest of the vehicle, large cross-section joints made of high-tensile-strength steel plating connect various sub-structures of the chassis. Three-dimensional steel plates are welded into the rear inner-fender to form a secure mounting point for the upper rear-suspension A-arm.

The Spyder's body/chassis unit, with its extensive network of welded reinforcements, is the foundation for a tight, smooth-riding and secure convertible.

SAFETY

Open-air driving enjoyment does not come at the expense of safety. As with other models, the Eclipse Spyder is fitted with a package of safety features designed to help enhance the safety of passengers in the event a collision does occur.

Mitsubishi Motors' engineers use the acronym RISE-Refined Impact Safety Evolution-as a design ideology that aims to take passenger compartment safety to an even 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 protecting occupants from the full force of collision impact energy.

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

Traction control is also included on Eclipse Spyder GTS when equipped with the Sportronic(TM) automatic transmission. The system uses minute computer-controlled front braking actions to slow a spinning wheel and restore traction. 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.

Passengers are further protected by a driver's and front passenger's airbag inflatable Supplemental Restraint System (SRS). In addition, the Spyder GTS includes dual front, side-impact airbags that can help minimize head and thorax injuries in side impact collisions.

CONVERTIBLE TOP

The Spyder's power-operated top features a high-quality, three-layer fabric with a separate polyester/cotton interior headliner, twin electric motors and a heated glass rear window. The engineering involved in the design of the retracting top helps make Eclipse Spyder a true all-season convertible.

The convertible top material starts with an acrylic outer layer that is solution-dyed before the threads are spun together. This coloring method ensures that the top's color will remain consistent for years, even at high-wear points like the frame/bow connections and window seams. The Spyder's top also incorporates a natural rubber second layer, which serves as a membrane between the acrylic outer and cotton inner lining. Rubber was chosen for its natural ability to hold its shape and resist shrinking and stretching.

The four rear structural bows of the convertible top frame are made of a rigid yet lightweight extruded aluminum material. These bows place significant tension on the cloth, while the die-cast aluminum front bow member and side rails are tailored to achieve a precise, aerodynamic fit with the windshield header and side glass. The Spyder's rear quarter windows rise straight out of the fenders and plug into "pockets" within the top seal. The windows themselves are fitted with a triangulated rubber strip at the leading edge, effectively fusing the front and rear windows when both are raised.

WARRANTY

The Eclipse Spyder 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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