Clayton Kinsler, auto mechanics teacher at West Philadelphia High School, scanned Locust Street to make sure it was clear of pedestrians, then hammered the throttle, rocketing the mean little coupe down the 4800 block.
The car's rear-mounted engine unleashed a primal, metallic roar, temporarily drowning out the jet-like whistle of the car's turbocharger.
A video crew from Discovery Channel Canada was also on the street that Saturday in March, filming what is arguably the country's fastest, most efficient eco-friendly sports car - and the West Philadelphia High School team that created it.
The asphalt-hugging, gunmetal-gray roadster was going through its paces in preparation for the Olympics of environmental auto competitions - the May 10-14 Tour de Sol in upstate New York. And much was riding on this car. The students were pretty sure they had worked out the major bugs.
Last year, the car won the race, garnering national attention for the team of about a dozen mostly African American vocational education students.
In February, the hybrid - which boasts 50 miles a gallon on soybean-based biodiesel fuel - got more media attention at the Philadelphia auto show.
If it won a second Tour de Sol victory, there'd likely be scholarships and well-paying jobs in the auto industry for the students - and badly needed grants, sponsorships, or even lucrative partnerships with major automakers for the city school's automotive academy.
Maybe Hollywood would come knocking.
For the moment, though, on Locust Street, it was time to cut loose and show off for the film crew.
At each high-speed pass by Kinsler, 47, the car's student builders whooped and cheered.
Then, zooming down Locust, Kinsler suddenly felt a loss of power. When he pushed the pedal, the engine revved, but nothing at the wheels. He coasted to a stop at 48th Street.
And sat there.
The students looked at one another and began walking, then running toward the car, as the realization dawned that something had gone horribly wrong.
Even as the video rolled, they swarmed around the car with pit crew precision and removed the engine cover.
Simon Hauger, 36-year-old head of the school's Electric Vehicle Team and mastermind of the project, peered into the tangle of wires, pipes and hoses.
"The axle's done," he announced. As he had feared might happen, the car's unorthodox axle had sheared in two.
Over the last year, the team and their instructors - Kinsler, Hauger, and shop teacher Ron Preiss - had overcome all kinds of obstacles:
How to instill in these urban students the value of hard work, responsibility, and a passion for learning when their environment outside of school often encouraged the opposite.
How to get the money to support the endeavor, which was beyond the school district's ability to fully fund.
And how to use unconventional thinking not just to succeed, but to blow away the world's expectations of them.
The axle - a thick metal rod that transfers engine power to the wheels - had required a lot of unconventional thinking. This was the fourth time in less than a year that it had broken.
The team had custom built the car from a kit called the K-1 Attack, with parts coming from different car makes. The axle presented a peculiar engineering challenge - the car's Volkswagen engine needed a way to spin its Honda rear wheels.
And so, the two rear axles are an amalgam of Volkswagen, Honda and parts-bin bits welded together. The left one, shorter and less flexible, is constantly breaking. A section of cheap steel pipe held its VW and Honda ends together, but the pipe tore under the high torque forces of acceleration. The car goes from zero to 60 in four seconds.
A thicker, higher-quality sleeve might do the trick, Hauger surmised.
A half-dozen team members pushed the stricken vehicle backwards, uphill to the school's garage, and gingerly rolled it onto the cradling metal arms of a power car lift.
Devereaux Knight, the 2005 team captain who'd gone on to one of the area's best technical schools, Automotive Training Center in Warminster, and a job at Central City Toyota, had dropped in. He draped an arm around Kinsler and teased him about his penchant for breaking axles: "Two for you, one for Hauger. "
The atmosphere in the garage was a mixture of adrenaline and disappointment, with team members half-jokingly asking that the mechanical failure be edited out of Discovery's video.
The only thing to do now was saw off new axle halves from whole VW and Honda units, send them out to be welded . . . and wait.
"We didn't expect it to break again," said a disappointed Joseph Pak, a lanky, earringed 10th grader with gel-spiked hair. Still, he said, he was relieved that it had happened well before the May competition.
For Pak and other team members who'd struggled with school, the car was an "in-your-face" affirmation of their talents and dreams.
Pak, the team's only Asian member, admits he used to skip more school than he attended. "I was just hanging out. " Now he gets straight A's and wants to be an engineer.
"I've seen the extreme of not doing things when you should," Pak said. With the Attack, he said he's seen the extreme of what happens when you stay the course.
It was now midafternoon and the French Canadian director was setting up his final shot.
"What you want to do is -" he began.
"Cry," Knight interjected.
Hauger, though, was upbeat. "This is actually pretty good news," Hauger said. Their more complex engineering of the axle had held. This was a simple weld.
The ideas that come out of West Philly's auto shop aren't rocket science, Hauger says, but they do require imagination and some risk-taking - traits he thinks Detroit could use.
He envisions the high school program sharing the team's know-how of building hybrid cars on the cheap. No major automaker sells a performance car that gets such outrageously high mileage.
With oil prices high and demand for hybrids soaring, the timing could not be better.
Developing a car model costs automakers about $1 billion. Even adding back the discounts and freebies the school team received - such as carbon-fiber body panels and custom wheels - the Attack would still have clocked in well under $100,000.
Hauger estimated their two-seater, if mass-produced, could sell for about $50,000.
But before such lofty ambitions could be realized, the Attack's axle had to be repaired.
Sixteen days later, during fourth-period auto mechanics class, a handful of team members gathered in the school shop. On a metal worktable sat the newly welded axle assembly. Machinists at Drexel University had augmented the original design with a beefier, higher-grade steel sleeve.
Kinsler motioned to the damaged axle, lying on the same table and looking like a broken femur.
"If you can't shift into second gear without something breaking, it ain't right," he said.
A student got under the car to pop the axle in place, much like pushing a tight toilet paper holder into place. Kinsler yanked on the suspension to create clearance. But, after many tries, it hadn't connected.
Quietly, Calvin Cheeseboro, a tall, athletic-looking 11th grader with neatly twisted braids, took over. Cheeseboro, who'd twice installed axles in the Attack and can practically assemble its complicated shift linkage in his sleep, now wrestled with the greasy metal rod.
First, the wheel-facing side popped into place. Then, with Kinsler again pulling on the suspension, the inboard side mated to the transmission with a satisfying clunk.
Classmates Bruce Harmon, a quiet senior who becomes animated when the talk turns to cars, and Jeffrey Daniels, a stocky 11th grader with nimble hands, ducked under the car to tighten clamps and make sure the piece was securely in place.
Cheeseboro, who has struggled to maintain passing grades so he can work with the team, said it felt good to be the guy to put in the critical part. Still, he said, he'd sooner not face such drama, especially with the May race fast approaching. "I don't want to break another axle. "
The team had hopefully resolved their thorniest problem.
They'd find out that afternoon, out on Locust Street, if their solution had worked.
Week of May 7: The Inquirer reports on the hectic days before West Philly's biodiesel challenges the best clean cars in the nation.