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The Case of The Raving Racer
Spring fatigue causes a race car to surge ahead at full throttle
Myron J. Boyajian, President, Engineering Consultants -- Design News, March 16, 2009
A Chicago-area drag racing team decided to "go pro" by upgrading its car from a time handicapped "bracket racer" to run in all-out races.
These racers lightened their car and installed a new camshaft, new cylinder heads and a new carburetor. Like many auto racers of every class and type over the past 100 years, they chose to defy the adage, "to make a small fortune in racing, you must start with a large fortune."
The Scene of the Crime
Modifications complete, they readied to go to the track. Firing up, they eased down the driveway from a rented garage to their trailer. On the street, the driver decided to do a tire-smoking burnout. The driver lifted his foot from the accelerator, but the car continued to surge forward at full throttle, overcoming the car's brakes. Just missing the trailer, the car veered toward the curb. The car ran across a lawn striking a neighbor who came out to see the racers' antics. The car then struck the injured man's house and stopped.
The injured man was hospitalized and the racers were ticketed. The smashed car was returned to their rented garage. The injured man sued, citing the race team for negligent vehicle operation, and the manufacturer of the carburetor, citing negligent design of the throttle system. I was retained to inspect the vehicle to determine the cause of the accident.
The Investigation
With little success, the attorney attempted several times to arrange a time for me to inspect the car. As time dragged on, I learned that not only did all these impecunious drag racers flee the area, they removed all the race goodies from the car, leaving the stripped hulk in the rented garage. This left only the carburetor manufacturer from which monetary damages could be recovered.
I dug into the police reports and pored over a bevy of photos taken by a police evidence technician of the car, engine and accident site. I noted the new carburetor with its throttle shaft and operating lever to which a stub shaft was mounted. The accelerator pedal linkage connected to this shaft. The stub shaft had a small, cross-drilled hole through which the eye of a tension spring was installed. The eye hung loosely as it broke from the body of the throttle return spring. With the spring eye trapped in the hole of the stub shaft, each rotation of the throttle shaft produced a bending stress where the eye joined the body of the tension spring. I surmised these racers used the existing spring from their prior race setup and long usage with improper installation fatigued the spring.
The Smoking Gun
Considering a possible failure-to-warn issue, I viewed the carburetor installation manual. Clearly shown, but not used by these racers, were dual springs connected with a bracket that isolated the throttle springs from the stub shaft rotation. Also, contrary to good racing practice, the racers failed to install a readily accessible steering wheel mounted ignition "kill" switch. The responsibility for this needless accident all fell on the shoulders of the now elusive racers. With no hope of recovery of monetary damages, the attorney dropped the case.
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I agree with the above comment. The proper spring arrangement in the article is standard practice for any reputable Drag Racer. I hate to see this sort of thing. You never do burnouts or test runs outside of the track, there is too much of a possibility of something going wrong even when everything IS done correctly. It just casts those of us that do know what we are doing in a bad light. I hope that these guys are caught and prosecuted to the full letter of the law.
Gary Ferringer - 2009-13-6 22:44:15 EDT -
Obviously these "racers" were not going by the sanctioning body rule book. As a former drag racer, I can state for sure that both IHRA and NHRA required, for many years, the double spring arrrangement on a carb if you wanted to make it through tech inspection. You might just get into a small time non affiliated track to bracket race, but either sanctioning body would have nailed them at the tech inspection.
James Edward Renninger - 2009-26-3 16:42:23 EDT
