GRANITE FALLS — Sara Rood inspected a tangle of electrical wires inside the Iron Maiden.

The student-built car has changed a lot since school started. Sara, 17, needs to know it inside and out. The Granite Falls High School senior will be the ShopGirls team driver in a prestigious fuel mileage competition at the end of the month.

“I’m the only one with a driver’s license,” she explained.

She’s also been part of ShopGirls, the school’s all-girl eco-car team, since 2010.

That year, they took a first place in the Shell Eco-marathon Americas event. Granite Falls won in the prototype diesel division after achieving 470 miles a gallon.

Sara and her teammates plan to reclaim their title in Houston.

The event, which runs March 29 through April 1, has high school and college students build their own cars and compete to travel the greatest distance on the least amount of fuel.

The ShopGirls’ three-wheeled, single seat Iron Maiden has been tweaked and retweaked to improve its chances of success.

It now has a toggle-switch ignition instead of a key and the car’s rear wheel was repositioned to keep its drive chain from falling off, like it did during last year’s event.

“I’m looking forward to definitely beating the old record and just doing our best and hopefully winning,” Sara said.

Another Granite Falls High School team is also working daily to make sure their car is ready to race.

Sophomore Jasmine Bates, 16, was part of last year’s co-ed UrbanAutos team that set a new Shell Eco-marathon Americas record of 186.5 miles per gallon in the UrbanConcept diesel energy category.

The event helped solidify the feeling that she was part of the team, Bates said.

“It was the real initiation,” she said. “We were there, we had to work together, and we were around each other all the time. It was fun.”

Students after last year’s competition designed a long tail so their car could be driven in September on a course at the Bonneville Salt Flats in Utah. A group of six students spent almost a week there and discovered that with the tail their car was faster, reaching a speed of 31 mph.

The team took some of what they learned in Bonneville and are adapting P219-D or Phillipe III — their new car — for the competition. Phillipe’s shorter tail is meant to make it more aerodynamic, Bates said.

They’re also working to lighten it up with changes that include replacing a cast-iron steering arm with aluminum and drilling holes in other heavy parts.

Competition rules limit cars such as theirs to 450 pounds or less.

Setting a competition record against cars built by college teams was exciting, but this year’s team has a new goal, Bates said.

“This year we’re shooting for 200 miles per gallon,” she said. “Hopefully we reduce the weight a bit, too.”

The five members of UrbanAutos and four members of the ShopGirls plan to leave March 28 for Houston.

They’ll compete against more than 100 other teams from throughout the United States, Canada, Mexico and Brazil.

The team members meet every day after school to work on their cars. Being part of the Granite Falls High School EcoTeams requires dedication and time outside of school manufacturing teacher Michael Werner said.

“It’s not just an hour after school, but it’s going to presentations, going to shows, going to competitions and working overtime,” he said.

Students learn teamwork and skills they can apply to a future career, Werner added. They also work with younger kids to promote an interest in the program. Students from Monte Cristo Elementary School were invited to the high school manufacturing lab last year to design the new tail for the UrbanAutos car. A couple students were given rides in the car as a reward for having the best ideas.

“One little girl, she got out (of the car) and said, ‘This was the most awesomest day of my life,’” Werner said. “That’s where you catch them … and in high school they want to be part of the real team.”

Freshman Dansil Green remembers attending a mini eco-car camp in June 2009. She still has one of the models that she built.

Now a member of the ShopGirls, Dansil, 15, is eager to experience her first Shell Eco-marathon Americas competition. Her goal is simple.

“I want it to work,” she said.

Amy Daybert: 425-339-3491; adaybert@heraldnet.com.