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Text that follows from 2003 Chevrolet SSR Press Kit, (PUBLIC DOMAIN) Copyright © 2003 General Motors
CHEVROLET SSR: THE ULTIMATE BOULEVARD CRUISER>
Some vehicles carry groceries, others go to work. Then there’s the Chevrolet SSR – the Chevy that loves to play.
Sure, the SSR is functional. But, come on, it’s really about experiencing the virtues of the SSR’s Chevy small-block V-8, its refined roadster handling and head-turning good looks.
“Nobody offers this much fun and function in a single package,” said Brent Dewar, Chevrolet general marketing manager. “I can’t think of a better way to get a suntan.”
The SSR is a vehicle that suggests it’s a throwback to simpler times, but it’s truly an invention of the 21st Century.
- It features large, flared fenders and a sculpted hood that come from a special steel stamping process.
- Power comes from a new aluminum block version of GM's Vortec 5300 5.3L small-block V-8 and drives the rear wheels through a four-speed automatic transmission.
- Its frame, chassis and bold stance evolved from Chevy's heralded TrailBlazer family of sport utilities.
- The retractable hardtop is an engineering marvel.
INNOVATIVE RETRACTABLE HARDTOP
One of the biggest challenges with the SSR was to enable the roadster design without impinging on the vehicle’s truck attributes. That is, how do you provide for a top for the passenger compartment without taking away from the cargo area when the top was in storage?
The answer is an ingenious power-retractable hardtop system that became one of the SSR’s most distinguishing features. The top, called a “top stack,” is the only system of its kind where the roof panels move independently to stack vertically behind the passenger compartment – a design that ensures quick operation and minimal stowage requirements.
A single button on the console transforms the SSR from an enclosed roadster to a convertible in 25 seconds, neatly tucking the roof panels rearward in waterfall fashion between the passenger compartment and pickup bed.
“As far as we know, this is the only retractable hardtop system with roof panels that actually operate independently, held together by a linkage as they move,” said Gary Forgue, chief engineer for the retractable roof system.
The design process for the SSR’s retractable roof system was completed in about four months – a remarkably quick turnaround considering the level of innovation incorporated. A team of engineers from General Motors, ASC Inc. and Karmann USA developed the system, which has been designed for long-lasting, reliable performance.
The push of a button transforms the SSR into a convertible in a smooth, quiet kinematic sequence orchestrated by the system’s controller using information collected from a series of sensors. The button that actuates the sequence must remain depressed until the entire event is complete; releasing it at any time temporarily halts the process.
Just as with the top-down process, pushing and holding the button converts the SSR back to a closed-cabin roadster. If the windows are up, the controller lowers them to allow the top to find its true position without interference from the door glass.
The controller also can detect the position of the door glass for optimal operation. For example, when a door handle is pulled, it drops the glass in that door just slightly to clear the seals. When the door is closed, the glass comes back up against its seals.
SSR FENDERS: SOMETHING OLD, SOMETHING NEW
The striking flared fenders linking the 2003 Chevrolet SSR to its innovative pickup past are the result of a process that very appropriately combines a contemporary forming technology with one used to produce the original 1947-1953 Advanced Design Chevy lineup of trucks, which inspired the SSR.
Even before production began, one of the first questions was whether the fenders could be cost-effectively produced of steel since shapes like that hadn’t been stamped in steel for decades, according to David F. Bjerke, lead body integration engineer for the SSR.
“The challenge was whether the fenders and rear quarter panels could be made with that much draw (stretching the steel in the dies to create the extreme curves of the SSR components),” Bjerke said. “The front fenders, for example, required about 10 inches of draw and the quarter panels are even more severe, as much as 18 inches.”
The draw, plus the many subtleties and nuances in the SSR fender and quarter panel shapes, posed a much more demanding forming challenge than the original pickup, which was produced when tolerances were much looser – 10 or 20 thousandths of an inch compared with only 2 to 3 thousandths of an inch today.
In the late 1940s, dies were much smaller and available stamping processes required numerous forming operations and a relatively large crew of employees. "Duplicating that effort today would have been prohibitively expensive", Bjerke said.
“Plus, nobody had made shapes like these for the last 15 or 20 years in a production vehicle,” he added. “Vehicle stylists have turned to body panels with much less severe shapes, which could be made with a different type of draw – a stretch draw – that didn’t readily lend itself to the shapes demanded for the SSR.”
GM co-developed a die and employed a stamping process, an inverted toggle draw, that is really a marriage between the old and the new – the original toggle draw stamping process and the more recent stretch draw concept.
“This approach, plus the use of new Grade 5 deep-draw quality steels, made it possible to produce the SSR fenders and quarter panels,” said Bjerke.
The interior theme is Chevrolet's twin cockpit approach, with a horizontal cross-car bar and body-colored accents bringing much of the vehicle's exterior theme to the interior. The billet aluminum look used on elements of the exterior continues on the door trim and instrument panel bezels. The clean instrument panel features gauges with bold graphics and a simple three-dial design for all climate controls.
CHEVY SMALL-BLOCK HERITAGE BUILT INTO SSR’S ALUMINUM V-8
The rich heritage of the Chevy SSR is much more than skin deep. A peek under the hood reveals the latest version of the small block Chevy V-8 that’s been the legendary leader of the street cruiser pack since the 1955 model year.
Chevy’s new Super Sport Roadster is powered by the new all-aluminum Vortec 5300 V-8. The original cast-iron Vortec 5300 is a staple of Chevrolet full-size pickups and SUVs.
“The all-aluminum version is refined to provide a quieter yet more aggressive driving experience for SSR owners,” said Chris Meagher, lead engineer on the Vortec 5300. “These refinements include performance, durability and noise improvements through the innovative use of structural materials, calibration and components.”
This aluminum Vortec 5300 is the latest iteration of Chevy’s original small-block V-8 engine that’s been the performance benchmark ever since it debuted October 28, 1954, in the ’55 Chevrolet Bel Air. That first small block was the 265-cubic-inch V-8, the first in a line of engines that are among the most popular ever built, with more than 70 million in 10 different displacements produced over the years.
When the first Chevy small-block V-8 appeared, it marked another major milestone in GM’s tradition of powertrain innovation, which began in 1911 when the Mason Motor Co. – a forerunner of GM Powertrain – was established. Powertrain milestones since then have included the first mass-produced V-8 in the United States and the first high-compression overhead valve V-8.
“The small block was a very lightweight, compact engine for its time,” Meagher said. “The best way to describe its design is ‘intelligent simplicity.’”
The all-aluminum Vortec 5300 continues the tradition of innovation. The aluminum block, for example, reduces the overall weight of the engine by 100 pounds compared with the cast-iron version. The engine capitalizes on the lower mass and thermal efficiency of aluminum, enhancing performance and fuel efficiency over its proven cast-iron counterpart.
Aluminum's thermal characteristics also provide improved heat rejection, resulting in cleaner emissions from faster catalytic converter "light off," faster heater core warm-up for vehicle occupants and cooler piston and oil temperatures for improved durability.
The engine block is produced by the gravity-poured precision sand casting process, which allows cylinder liners to be cast in place and yields excellent cast quality. The engine is tested to identical levels of endurance as the cast-iron Vortec 5300 engine.
The engine also features new quiet-profile pistons to ensure that the pistons track straight in their bores, minimizing clearances as the pistons rock under gas pressure.
The pistons are polymer coated to reduce cold scuffing and engine noise. Polymer-coated pistons, long a mainstay in luxury car engines, enable tighter bore clearances, provide enduring wear surfaces between pistons and cylinder walls, and further reduce piston motion.
In addition to the aluminum block, the SSR engine gains other mass reductions through use of a new oil pan design.
Exhaust catalyst and emissions control system calibration have been improved to allow the engine to meet federal emissions and California Low Emission Vehicle (LEV) standards without an exhaust gas recirculation (EGR) system.
Like its iron sibling, the aluminum engine uses platinum-tipped spark plugs to extend plug life to 100,000 miles, while the coolant maintains its cooling and corrosion-inhibiting properties for 150,000 miles. Scheduled maintenance is limited to oil changes when indicated by the engine oil life monitoring system or at 10,000-mile intervals, whichever comes first.
A large 25-gallon fuel tank provides an extensive driving range between fill-ups.
TRANSMISSION A PROVEN PERFORMER
Just as the small block V-8 provides a heritage of power, the SSR's transmission is a proven performer. It’s GM's Hydra-Matic 4L60-E, an electronically controlled, four-speed rear-wheel-drive, automatic overdrive transmission with a torque converter clutch.
The 4L60-E, also used in GM trucks and the Chevrolet Corvette, was selected for its durability, low weight and the ability to optimize its electronic controls for performance-oriented shifting.
The electronic controls are calibrated to give the dependability of a pickup and the performance of a super sport vehicle.
To multiply engine torque, the 4L60-E uses a 300-mm torque converter. The converter is enclosed in a 360 degree-mount structural bell housing for powertrain rigidity.
TORSEN SYSTEM HELPS GET POWER TO THE ROAD
Chevy SSR drivers will know they can count on a great GM small-block V-8 to motivate those big rear wheels. In addition, SSR will have a true performance-car proven system to make sure that power gets to the road with great traction and control.
The SSR will feature a Torsen Traction Differential on the rear axle. The Torsen differential distributes the engine's power to the wheel with the most traction, reacting instantly before any wheel slip can occur. The Torsen system for the SSR is a close relative to the rear differential developed for the Chevrolet Camaro and is the technology of choice for numerous racing teams.
"The Torsen differential will work seamlessly with the standard traction control system to give the SSR strong performance in driving maneuvers such as aggressive acceleration and cornering and the wide variety of road conditions," said Lori J. Cumming, chief engineer for the SSR.
The Chevy SSR will feature an engine-based electronic traction control to manage the level of power, while the Torsen differential provides an extra measure of traction with its precise distribution of power.
RIDES ON A STRONG FOUNDATION
The design and functionality of the Chevrolet SSR combine to form a striking exterior package. But underneath the surface lies a strong foundation that represents advanced GM technology tailored for the unmistakably unique Chevy SSR.
The production version of the SSR has a frame with fully hydroformed steel side rails. The hydroformed frame features great strength and stiffness, relatively low weight and precise quality.
“The hydroformed frame provides an extremely strong foundation for the overall performance of the SSR, with great torsional rigidity and dimensional control,” said Lori J. Cumming, the SSR’s chief engineer. “A traditional stamped frame with this amount of strength and rigidity would weigh roughly 20 percent more than this one. That strength allows the frame to take on the road inputs, which lets the suspension do its job precisely.”
Hydroforming is a technology in which steel tubes are precisely shaped through the application of water at extremely high pressure. It replaces traditional stamping processes, preserving more of the steel’s strength and stiffness as it goes through the forming process. Hydroforming is done at low temperatures, which retains the material's strength throughout the forming process, unlike high temperature processes that decrease material strength. Hydroforming also is efficient and environmentally friendly because it dramatically reduces overall material usage and scrap.
GM pioneered automotive hydroforming on the Chevrolet Corvette and used this process for the first time for a truck frame on the Chevy Silverado, Tahoe and Suburban. The 2002 Chevy TrailBlazer marked the first time hydroforming was used for the entire length of a truck frame’s side rails.
For the SSR frame, the holes for suspension attachments are laser-cut, providing great dimensional accuracy measured to meet minute standards. This gives engineers maximum control of suspension components, allowing them to tune the suspension more precisely.
The frame features eight cross members – four or six are typical – also boosting structural strength for ride quality, handling, and noise and vibration reduction.
In addition, the entire frame is electrostatically coated, rather than wax coated. This type of coating process improves protection from the elements.
The SSR’s 116-inch wheelbase is optimized to maintain truck functionality and to offer exceptional passenger room, yet it also allows for a tight turning radius generally associated with a smaller sized vehicle.
The battery is located at the rear – something street rodders have done for years – for better overall weight distribution while preserving front styling. The improved weight distribution yields better steering response, tire wear and full use of the friction circle, extracting the greatest capability from every tire. And, the battery lasts longer since it is away from the heat of the engine.
FINELY TUNED RIDE AND HANDLING
The SSR’s independent front double-A arm and rear five-link live axle suspension is specifically tuned for the SSR’s ride and handling characteristics, while providing durability for on-road truck use.
The front suspension configuration incorporates upper and lower control arms for superior kinematics, damping and stability, which, when combined with rack-and-pinion steering, provides smooth, precise control.
The rear suspension includes monotube shock absorbers for optimal damping, shock absorber mountings outside the frame to enhance body and wheel control, steel coil springs for consistent ride height, and a microcellular urethane auxiliary spring for enhanced ride comfort and stability in fully loaded conditions.
The SSR has a lower stance and wider track than the General Motors mid-size sport-utility platform on which it is based. This provides a lower center of gravity for increased stability and flatter cornering.
Spring rates, internal shock valving, urethane jounce bumpers and rubber bushings are all specifically tuned to create the SSR’s unique ride and handling characteristics.
The body mounts, while usually not thought of as part of the suspension, were also specifically and individually tuned in three directions to balance ride and handling requirements. By adding or adjusting damping and rates in the body mounts at specific locations, the engineers were able to tune out harshness, while minimizing body flex and the usually detrimental handling effects of compliant body mounts. The result: a better balance between ride harshness and handling performance.
TRACTION AND CONTROL
Standard electronic traction control, a Torsen differential and 20-inch tires on the rear axle ensure that the power of the Vortec V-8 engine gets to the pavement with exceptional traction and control.
The Torsen differential works seamlessly with the traction control to maximize performance in driving maneuvers, such as aggressive acceleration and cornering, and over different road conditions. It is a close relative to the rear differential developed for the Chevrolet Camaro and the technology of choice for numerous racing teams.
Responsive steering and brakes, beefy wheels and tires
The hydraulically assisted rack-and-pinion steering has a 16:1 steering ratio that yields quick response and enhanced maneuverability. Its wheel turn angle provides excellent maneuverability, minimizing the number of steering wheel turns required for tight cornering.
Four-wheel vented disc brakes with ABS and dynamic rear proportioning provide outstanding stopping performance and brake feel, reduced wear and low noise.
The SSR’s 19-by-8-inch front and 20-by-10-inch rear aluminum wheels are among the largest GM has ever used on a light-duty truck. The large wheel sizes accentuate the striking, custom-styled appearance of the SSR. Its huge wheels, enhancing its road presence, elevate it to the stature of a true roadster. Created with the same proprietary technology as the Corvette’s, they feature “flow formed” outer flanges for outstanding load-bearing strength.
The on-road low profile P255/45R19 front / P295/40R20 rear Goodyear radials are specially formulated and designed for the SSR’s unique ride and handling requirements and contribute to its aggressive look. The wide tread size serves a dual purpose in providing great handling and a muscular stance.
The asymmetrical tire and wheel sizes are faithful to the unique stance of the original SSR concept vehicle.
The H speed-rated tires with asymmetrical circumferential grooves add to the Eagle RS-A all-season capability. Steel- and nylon-reinforced tread belts enhance the tires’ steering response.
The wide tread width delivers excellent dry traction, and higher lateral stiffness on the tire outside shoulder offers improved dry handling. Lower stiffness and increased blading on the inside shoulder of the asymmetrical tread pattern provide increased wet- and snow-traction.
Total prodution for 2003 model year was 3,416 units*. Click here for production detail.
*Excludes the 25 Signature Series trucks and 2 others, all painted in Ultraviolet.
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