Sherri Singer
Assistant Editor
No one can accuse Trans-Am racers of being technophobes. The early years of racing were marked by rumors that some owners dipped their car bodies in acid to melt off excess weight and lower the center of gravity. Built with a thin margin for error, the cars were known for sometimes falling apart on the track. The quest for speed came first, with little concern for safety.
The early no-holds-barred approach to building these modified stock cars has evolved into a more standardized and high-tech competition. Trans-Am cars, like Nascar racecars, are basically tube frame chassis attached to a stock car body replica. Compared to their early days, there are far-reaching rules that spell out how the cars can be built. For example, all vehicles must use the same sort of chassis, made by any of only seven suppliers: Rousch, Riley & Scott, Weaver, Selix-Weaver, Pratt & Miller, Hoerr, and Rocketsports.
Engine block and cylinder heads must be the standard equipment for the manufacturer’s street model, or an approved alternate. The most commonly used combination is the 311-in.3 V8. The crankshaft, connecting rods, and camshaft are unrestricted, and rules prohibit any type of turbo or supercharging.
Every Trans-Am vehicle must use an 8,200-maximum rev limiter. Rules dictate a coil-over-shock front suspension with a live-axle rear end. Active suspension, telemetry, traction control, and ABS brakes are not allowed. But, chassis data-gathering systems are okay.
LOOKING FOR THAT TECHNICAL EDGE
Ever-tightening rules force Trans- Am racers to become more clever about finding a technological edge. Examples of some current strategies can be found on the car run by Johnny Miller, driver of the #64 PLCDirect Chevy Camaro. Miller was named the 1996 rookie-of-the-year, finishing 13th overall in the Series with 147 points.
Looking for ways to advance technology in racing, PLCDirect, sponsor of Miller’s Camaro, tested its new factory automation product in an extreme environment, the racecar. The Direct- Touch operator interface is a touch panel that looks like a laptop computer screen. In its usual operating mode, the panel displays graphical and text data that keep machine operators aware of what’s going on with factory-floor equipment.
Miller’s Camaro carries a PLCDirect operator interface in its trunk. A screen sits inside a metal box along with a programmable logic controller and a video camera. The PLC gathers information about the car such as speed, rpm, g forces, and cockpit temperature. It then applies the necessary conversion factors to the raw sensor signals and displays the data on the screen.
For example, the PLC counts signals from a pulse generator attached to a wheel to compute car speed. It displays data on the screen in the form of simulated dial gages and digital readouts.
The video camera is aimed at the screen. A transmitter beams the resulting images to a TV crew covering the race. The TV audience can watch the changing readouts as the car hits 180 mph and steers past concrete walls and other vehicles. The PLC, camera, and associated electronics must be rugged enough to work in temperatures that average 110°F.
The PLC saves the data it receives so Miller’s team can review it after the race. “The data acquisition system provides a great show for the fans while proving that the product holds up under adverse conditions,” says Miller. The team may have the electronics track shift points and the gear being used in the future.
CLUTCHLESS SHIFTING
The 311-in.3 V8 power plant that pushes most Trans-Am cars to 185 mph is a push-rod engine with a valve-train movement that is notoriously hard to control. Valve-train problems tend to emerge when the engines hit high rpm. The future of the Trans-Am Series appears to be in overhead cam engines which can take higher rpm with less trouble. Toyota is slated to run its overhead cam, multivalve engines in future Series.
A look at the Trans-Am body, undercarriage, and drivetrain confirms the fact that these are racecars, not your father’s Oldsmobile. The vehicle’s body parts are carbon-fiber Kevlar honeycomb composite. The Rocketsports chassis is chromoly fabricated steel tubing with titanium and carbon fiber for fire and heat protection.
A five-speed Hewland ST transmission allows shifts without using a clutch. The driver only uses the clutch when pulling away from the pit area. The “dog ring” transmission uses the accelerator to release and change gears. It is the same transmission found in Indy cars, installed sideways behind the motor. Eliminating the clutch cuts shift time down to a tenth of a second. However, the transmission has a relatively short life and is pricey at $15,000 per unit.
An independent front suspension employs control arms and coil-over shocks. The rear suspension is a solid axle with multiple connecting links and coil-over shocks. Three-piece modular alloy wheels are 16 × 12 in. front and rear. Mandated BFGoodrich tires measure 25.5 × 13 × 16 in. on front, and 27 × 14 × 16 in. in the rear. Exhaust systems are also required, with a maximum sound level of 107 dB.
The fuel system includes a fuel cell. Unlike conventional metal tanks, the fuel-cell system incorporates a rubber bladder full of very porous foam, which holds approximately 32 gallons of 116-octane fuel. If the tank is punctured, the flexible material bladder keeps fuel from spraying, eliminating a potential hazard.
RACE DAY ARRIVES
It takes about 100 hr of maintenance work to get ready for a race weekend. A catastrophe such as engine failure or a crash can boost that figure dramatically. The crews works 15 to 18-hr days to keep the car running while racing. Race-day preparation for drivers requires mental and physical concentration on the race. Miller, for example, follows a specific diet designed for high energy and drinks water frequently to stay hydrated. Small wonder, cockpit temperatures regularly exceed 100°F. Dressed in three layers of fireproof clothing, drivers must wear a “water jacket” filled with circulating ice water to prevent heat stroke.
The crew chief or team engineer controls the technical aspects of the car such as the data system, shock settings, spring rates, and engine adjustments. Both Miller and his crew chief Scott McLearen work closely together to get optimum performance. Miller, a degreed engineer himself, believes his extensive knowledge of the car helps when tuning to get the best performance.
“If you know how the car works you can communicate with the crew chief on options for correcting problems during practice or qualifying,” he explains. “If I say the car is pushing, meaning it goes straight when I turn the wheel, I can say we need a left front spring or swaybar, or more rear spring or swaybar.” Less technically knowledgeable drivers often have trouble explaining their car’s behavior to their crew chief, Miller claims. The process of tuning the vehicle for track conditions can be more laborious as a result.
Trans-Am Series cars are extremely adjustable, according to Miller. This is a double-edged sword. He only has about 10 min to communicate with McLearen about what’s wrong during qualifying, discuss fixes, and hopefully make the right change.
Though good technology helps, success in racing, Miller surmises, requires “A great driver, great car, and great team.”
THE BAD BOY ERA BEGINS In 1967, Mark Donohue began a five-year run that made a name for himself in the Series. He scored 29 victories, 43 top-three finishes in 55 races, and finished on top of the drivers’ points standings three times. Driving a Camaro for Roger Penske, Donohue continued to battle through the end of the 1960s, waging battles with Parnelli Jones’ Ford Mustang for the entire 1969 season, and winning six of seven races. The 1970-71 season featured American carmakers pitted against each other with AMC Javelins, Ford Mustangs, Chevy Camaros, Dodge Challengers, and Plymouth Barracudas. In 1970, Parnelli Jones won the Drivers’ Championship. Donohue, in his AMC Javelin, won the 1971 Drivers’ Championship, making AMC the winner among the carmakers. These were the Series golden years, before the fuel crisis and major rule changes occurred. The first major rule change for the Series occurred in 1973. FIA’s Groups 1, 2, 3, and 4 Touring and Grand Touring cars became eligible to compete, along with the SCCA’s Sedan Classes A and B. By 1974, the Series reached an alltime low, conducting only three races. In 1975, restructuring occurred because of the fastest production car classes. Group 4 and 5 cars were added in 1976, and the Series went to a two-class system. However, the exotic Category II class was very expensive, and eliminated by 1979. Reformatting in 1980 was done by using a system based on engine size-to-car weight, with the addition of tube-frame chassis which remains today. The Series consisted of 5-liter power plants weighing 2,600 lb. In 1996, the Series celebrated its 30-year anniversary with drivers such as Paul Gentilozzi, Dorsey Schroeder, Tom Kendall, and rookie-of-theyear Johnny Miller. Tom Kendall broke Donohue’s Drivers’ Championship record in 1997 and also received the AARWBA Driver of the Year award. Kendall’s winning year captured the national media’s interest in the Trans-Am Series. Today, a new title sponsor, National Tire and Battery, and BFGoodrich, as the series spec radial racing-tire supplier, join the Series for a new era in muscle-car road racing. |
TRANS-AM RACING GAME GIVES ARMCHAIR DRIVERS THE REAL THING Visualization technology and 3D imagery work to capture the roughness of the Trans-Am Series. Racetracks will mimic the longer, closed-track style featuring minor elevations and obstacles such as trees close to the track. The vehicle physics feature six degrees of freedom — a crashing car rolls, pitches, and bounces. Dr. Al Lynch, EAI vehicle dynamics expert, lends authority to the physical and collision modeling. Braking force noses down the vehicle. As the vehicle accelerates, the rear end squats down with the help of spring effects. Lynch’s physics are readily apparent in crashes when a car flips end-over-side after hitting a corner embankment at high speed. The impact vector, energy, and forces involved all go into calculating the crush effects. Each vertex on the car mesh has a crush parameter so points that are crushed move in, distorting the polygon in realtime to reflect the impact. Pit crews will be able to bang the dents out of 13 classic car makes and models, but different team paint schemes will make the number of selectable vehicles higher. The game will also feature 19 real Trans-Am drivers and 13 tracks of the era. A 3D cockpit will be modeled for each car, letting players glance left or right. Apex tracking pans a camera view into the turn the way drivers naturally turn their heads. Opposing drivers are modeled after famous Trans-Am racers to make players feel they are racing other drivers rather than just cars. A single-player race puts drivers behind the wheel against 19 other nonplayer cars, while as many as 16 players can compete in the multiplayer mode via LAN or the Internet. Effects include smoking brake pads after brake lock up, and three colors of smoke that signify different problems with the engine. Audio will complement all the visual features with a sort of 3D sound and ambient effects. For a finishing touch, an announcer calls the action, complemented by a rock soundtrack. |
TIGHT RESTRICTIONS Technical administrators mark the tires which must then be used for all qualifying sessions and to start the race. Only one tire can be substituted for a similar tire. If more than one tire is substituted, starting position is forfeited and the driver starts at the back of the grid. |