Chevy Colorado Mid-Size Pickup

The all-new 2004 Colorado puts Chevrolet on the map in mid-size pickups with a combination of power, comfort, utility and good looks that sets new standards for the segment.

"Colorado is large, spacious and has many combinations and configurations to appeal to a broad base of customers," said Janet Eckhoff, Colorado marketing director. "The heart of any truck is its powertrain - and that's an area in which Colorado is particularly strong, with two smooth, powerful and efficient engines.

"Colorado really does set a whole new standard for mid-size pickups," Eckhoff added. "This is a personal-use truck for singles, couples or families who want more out of their mid-size pickups, but who still share one thing in common: Any truck they drive had better be 'a real truck.' As soon as buyers see and drive Colorado, they'll discover that this truck delivers on that promise."

Colorado marks the fifth all-new Chevy Truck since the announcement of the Chevy Avalanche at the 1999 North American International Auto Show. Colorado production will begin at the General Motors Shreveport truck plant in Shreveport, La., in the fourth quarter of 2003.

'Real truck' styling and design
Aerodynamic and contemporary, Colorado sports an athletic stance. Up front, a prominent gold Chevy bowtie, set against a grille bar, reflects Colorado's Chevy Truck DNA.

Colorado covers the segment with nine model configurations, including three suspension packages (standard, sport and off-road), three cab styles (crew, extended and regular) and two- or four-wheel drive.

Inside, Colorado looks and feels more like a spacious, well-appointed full-size pickup than a typical mid-size truck. It brings a new level of comfort and capability to the segment, with craftsmanship and attention to detail evident throughout. With crew cabs comprising almost one-third of the mid-size pickup market, Colorado's crew cab offers a 60/40-split folding rear seat capable of accommodating three adults. The extended-cab model comes standard with four doors. And the regular-cab model features 60/40 bench seats, in cloth or vinyl, with bucket seats available.

From its superb torsional rigidity to its aerodynamically efficient exterior, Colorado was designed to be the smoothest, quietest pickup in its class.

Rugged, rigid and versatile
With its ladder-type frame, Colorado's chassis meets or exceeds every design target for torsional stiffness and durability. Independent front suspension and a live rear axle are standard on rear-drive models, as is torsion-bar suspension on four-wheel-drive models.

Colorado's standard anti-lock brake system (ABS) was designed for heavy-duty service, with tandem power boosters, dual-piston disc front brakes with audible wear sensors, and 295-mm diameter rear drums. Fifteen-inch wheels and tires are standard, with step-up optional aluminum wheels available. Rack-and-pinion steering is standard.

Colorado offers several traction assistance options. The shift-on-the-fly 4WD system is activated with a dash-mounted switch. A new segment-first locking differential is available on rear- and four-wheel drive models with either the four- or five-cylinder engine along with a segment-first traction control option on rear-wheel-drive models.

Colorado is first in its class with optional roof rail side air bags. Dual-stage front air bags are standard; on the regular-cab model, the passenger-side air bag can be disabled. A battery saver system is standard on Colorado as well. Options include a remote locking system, heated seats, the OnStar safety and security system, XM Satellite Radio and a driver information system including an oil life monitor.

Advanced powertrain choices
The 2004 Chevrolet Colorado will feature new inline five-cylinder and four-cylinder engines that will provide the power of a V-6 and the efficiency of an I-4. The Vortec 3500 and Vortec 2800 are derivatives of the award-winning Vortec 4200 six-cylinder engine featured in the TrailBlazer and TrailBlazer EXT.

With their common design, the new I-5 and I-4 engines feature the same all-aluminum construction, dual overhead camshafts and four-valves-per-cylinder technology as the Vortec 4200. The new engines also share the I-6's high 10:1 compression ratio, electronic throttle control, exhaust cam phasing, coil-on-plug ignition, direct-mount accessories and easy maintenance features.

The cast aluminum four- and five-cylinder engine blocks and aluminum cylinder heads are produced using the same lost foam casting process as the Vortec 4200. This process allows more exact dimensional control while reducing machining efforts in oil galleries, coolant and other internal passages.

Overall, the new engines share 75 percent of their components with Vortec 4200 and 89 percent of their components with each other. This provides customers with highly proven design features and enables GM to develop and introduce them more quickly and at a lower cost.

The Vortec 3500 I-5 will produce 220 horsepower and 225 lbs.-ft. of torque. The Vortec 2800 I-4 will deliver 175 horsepower and 185 lbs.-ft. of torque.

"The real key to these engines is that they're part of a carefully planned and developed inline family," said Ron Kociba, Vortec inline engine chief engineer. "The Vortec 4200 I-6 was the first and the I-5 and I-4 take advantage of much of the same technology to provide the same benefits for Colorado customers as the I-6 provides in the TrailBlazer."

Distinguishing features
A major differentiating feature between the Vortec 3500 and 2800 engines is their dual balance-shaft system. The balance shafts offset secondary forces inherent to inline engines and help to provide smooth, quiet operation throughout the entire operating range.

Incorporated into housings on each side of the engine block, the balance shafts rotate in opposite directions of one another at twice engine speed, countering secondary forces generated by piston movement. They help eliminate vibrations that drivers and passengers might otherwise feel transmitted through the engine mounts to the steering wheel, seats, floor pan or instrument panel.

A rigid block structure and well-balanced crankshaft are also key to low noise, vibration and harshness. The Vortec 3500 crankshaft is optimally counterweighted for its five-cylinder design. Many of the same features used to control noise and vibration on the I-6 engine are found in the I-4 and I-5, such as isolated cam covers and acoustic foam treated induction manifolds, as well as attention to detail in the design process.

A unique manifold-mounted converter - a three-way catalyst constructed as part of the exhaust manifold - also sets the I-5 and I-4 engines apart from the I-6, and enables them to meet foreseeable future emissions requirements with no change in basic configuration. The new engines are designed to meet Federal Tier II / California Low Emission Vehicle II (LEV II).

Close-coupled catalytic converters provide optimum initial "light off" (quick, high temperatures), primarily for oxidizing hydrocarbon and carbon monoxide emissions, with an under-floor catalyst burning the majority of remaining gases.

The engines' exhaust cam phaser is a common feature to the Vortec inline engine family used to enable variable valve timing (VVT). This technology allows more freedom in cam profile selection, which enhances power and torque. It also improves idle smoothness, reduces emissions and improves fuel economy.

VVT is used to time and regulate the opening and closing of the exhaust valves. The valve timing is electronically controlled and programmed for optimum emissions, torque, smooth idle and driveability.

Increasing the overlap of the cams, or "retarding the exhaust cam," creates internal exhaust gas recirculation (EGR) in which gases are evenly distributed to all cylinders. Leftover gases are simply recycled into the next burn cycle - an enabler for emissions control also providing high output and smooth idle.

The new engines use a more powerful, next-generation powertrain control module (PCM), with a new GM common design. The PCM manages all engine and transmission functions and communicates with other electronic vehicle controls. The new PCM provides quicker response time and has flash programmable memory, allowing quick and easy reprogramming to accommodate new features and updates. GM is pursuing commonality in its PCMs to reduce engineering time and cost and to help bring new vehicles to market more quickly.

Technology highlighted
Among the Vortec 3500 and 2800 key features:

Standard electronic throttle control (ETC) allows precise tailoring of throttle progression in each of the engines to meet its particular character. ETC optimizes driveability, fuel economy and emissions control, and enables other functions, such as cruise control, brake-torque management and traction control, available on two-wheel-drive models.

A controller, integrated into the dual microprocessor PCM, manages the electronic throttle. Based on information from two independent throttle position sensors and other data, such as the transmission gear and traction at the wheels, the PCM directs an electric motor to open the throttle at an appropriate rate.

The coil-on-plug ignition system delivers a high-energy spark, which contributes to clean and consistent combustion, enabling compliance with emissions and onboard diagnostic misfire requirements. The electronic engine-sensing and spark control system also contributes to improvements in fuel economy, high-speed performance and engine efficiency. It has no moving parts, requires no timing adjustments and eliminates the need for spark plug wires.

The roller follower valvetrain and state-of-the-art PCM also improve engine performance, efficiency and noise levels.

An intelligent start feature prevents drivers from inadvertently engaging the starter on these smooth, quiet engines when they are already running.

Smooth-shifting transmissions
Available with both the Vortec 3500 and 2800 engines is the precisely controlled, smooth shifting Hydra-Matic 4L60-E 4-speed automatic transmission. Used in all of GM's light-duty applications, it has a long history of customer-pleasing performance and dependability.

Both the Vortec 3500 and 2800 also link to a standard new high-torque capacity five-speed manual transmission. Used by GM for the first time, it provides smoother, higher quality shifts; better launch; improved durability and a higher degree of fuel efficiency.

"The American public discovered the inherent advantages of inline engine technology with the introduction of the TrailBlazer, and this year they're going to realize the same thing in the Colorado," said Bruce Mader, Colorado product manager. "Both the four- and five-cylinder inline engines simultaneously deliver greater horsepower and greater fuel economy, making them among the most advanced engines in the world. These powertrains are indicative of just what a 'true Chevy truck' Colorado really is."