2004 Mitsubishi Diamante Technical highlights

ENGINE

The Diamante comes equipped with a smooth, powerful 3.5-liter, SOHC, 24-valve V6 engine that produces 205 horsepower (210 hp for the VR-X) at 5000 rpm and 231 pound-feet of torque at 4000 rpm. The additional power in the VR-X version is the result of a freer-flowing exhaust system. The Diamante's large V6 propels the contemporary, near-luxury sedan from rest to 60 mph in 8.1 seconds.¹

Several proven engineering technologies are brought to bear here, including a naturally smooth 60-degree cylinder arrangement, durable cast-iron block, weight-saving aluminum heads, quiet belt-driven camshafts and friction-reducing roller-type rocker arms. Hydraulic valve lash adjusters eliminate the need for periodic adjustment.

The 3.5-liter engine's combustion chamber is a compact pent-roof design for high combustion efficiency and low exhaust emissions. In addition, the spark plug is located at the center of the chamber for faster, more stable burning. The breathing characteristics of the engine's four-valve design allow for improved airflow and power.

Mitsubishi's engineers used computer-aided techniques to achieve engine rigidity and reliability. This includes determining the optimum thickness of the engine's cast-iron cylinder block, and where to place its stiffening ribs. A forged steel crankshaft is employed in the reciprocating assembly for better durability.

The engine crankshaft rotates in heavy-duty, four-bolt main-bearing caps, which are linked together by a full-web girdle. This arrangement is designed to increase engine smoothness, enhance engine rigidity and reduce vibration from crankshaft flexing.

TRANSMISSION

The Diamante ES is equipped with a four-speed, electronically controlled automatic transmission featuring Mitsubishi's Adaptive Shift Control, which enables the transmission to rely on "learned control" to tailor shifts to the driver's style. The engines in the LS and VR-X trim lines are mated to a Sportronic(TM) transmission, which can operate in traditional fully automatic mode, or the driver may choose to actuate clutchless shifts for more spirited driving. The Sportronic(TM) INVEC-II system learns a driver's throttle inputs and adapts to them by modifying its shift pattern. A four-position shift lever with a Sports-mode gate allows drivers to experience sporty, positive-feeling manually actuated shifts with a simple push or pull of the shift lever.

In fully automatic mode, the Sportronic(TM) 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.

SUSPENSION

The Diamante's confident handling is the result of a well-conceived fully independent suspension that utilizes a MacPherson strut design up front and a multi-link setup at the rear.

For superior durability, the suspension's front struts use a large, rigid cross section design that resists bending and twisting. This helps to lead to more precise control of wheel geometry and consistency in handling. The lower arm of the suspension is attached to a precision-cast aluminum crossmember, which is much lighter than a conventional steel design and provides more accurate wheel alignment. Rubber bushings isolate the crossmember from the body, and the lower arm is mounted to the crossmember using liquid-filled bushings that absorb vibration, road harshness and noise.

The sophisticated rear multi-link design consists of a pair of high-mounted upper A-arms (wishbones), two lower trailing links and four lower transverse, unequal-length control arms. The upper wishbones are connected to the lower links through long "twisted" arms, providing a mounting point for each wheel hub. The configuration and geometry of the upper arms resists bending forces from camber changes while also providing excellent straight-line stability.

The suspension provides excellent stability when accelerating, and reduces body dive and squat under braking. The Diamante's chassis tuning includes front and rear stabilizer bars, which control body roll during cornering. The rear stabilizer bar and trailing links are mounted by pillow-ball bushings, which provide smooth, progressive roll control and reduce rear impact harshness.

STEERING

All three Diamante models come equipped with speed-sensitive, power-assisted rack-and-pinion steering. Requiring only 3.1 turns-to-lock, the quick response and reassuring feel of this system provide constant input about the road surface and the car's directional dynamics. The variable assist of this system is subtle but effective. It adjusts simultaneously and seamlessly with engine speeds, resulting in greater assist for low-speed maneuvering, such as parallel parking. As speeds increase, the steering's reduced power assist helps provide more road feel, which helps the driver maintain directional stability.

BRAKES, WHEELS & TIRES

To provide confident stopping power, four-wheel disc brakes are part and parcel of the Diamante's high level of performance equipment. The brake system includes antilock brakes (ABS) to help enhance steering control during emergency avoidance maneuvers. Electronic Brakeforce Distribution (EBD) further aids braking by monitoring traction conditions and applying hydraulic force to the front or rear brakes where it will do the most good.

The Diamante features standard V-rated P215/60R16 all-season performance tires wrapped around stylish six-spoke alloy wheels.

SAFETY

The Diamante incorporates numerous technologies designed to help enhance occupant safety in the event of a collision. Mitsubishi Motors' engineers use the acronym RISE-Refined Impact Safety Evolution-as a description of their goal to take safety to an even higher level.

A number of elements, such as high-rigidity side members, roof reinforcement, large-section side sills, door frames and side-guard beams combine 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 the occupants.

Even the crossmember that supports the steering column helps protect passengers. This crossmember acts as part of the front bulkhead and helps to increase resistance in a front impact. It also helps to add rigidity in the event of a side impact.

In addition to the already mentioned antilock braking system, a traction control system (TCL) is available as part of the Cold Zone Package on the LS model. In its most basic form, TCL prevents the drive wheels from spinning on slippery surfaces. When the system detects an excessive slip ratio, the TCL microprocessor works in conjunction with the engine management system to momentarily reduce power until maximum driving force can safely be regained.

In the event of a collision, the Diamante is equipped with a driver's and front passenger's airbag Supplemental Restraint System (SRS). In addition, driver and passenger seatbelt pretensioners are designed to tighten the belts, keeping occupants secure against the seat. The pretensioners work in conjunction with the seatbelt force limiters, which gradually ease pressure on the shoulder belt during an impact situation once a predetermined load is reached. The force limiters essentially decelerate the passenger, helping to reduce the impact load in the event of a frontal impact.

WARRANTY

The Diamante 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 and restraint systems are 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 making hotel and rental car arrangements and contacting family members.

1. Motor Trend.com Buyer's Guide, September 20, 2001

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