Fourteen Alden-Conger High School students built a car that gets 866 miles per gallon. Their secret? They take what they already know and build on it.

It’s that knowledge that helped them take first place in the design proposal portion of the 20th annual Supermileage Challenge presented by the Minnesota Technology Education Association — the reason for building the car.

“It’s a learning experience for these kids,” said science teacher Dave Bosma.

In addition, the supermileage car placed second in the modified class May 19 and 20 at the competition at the Brainerd International Raceway and Resort.

Students on the Alden-Conger team also built a stock car, which took fifth in the class, and an E-85 car that didn’t place because it wasn’t able to get enough runs around the track.

One hundred cars competed in the MTEA Supermileage Challenge with the goal to build the car with the highest mileage run of the year.

The car entered in the modified class by Alden-Conger students was the car with the highest mileage at 866.66 mpg.

Alden-Conger students have entered the competition for at least 12 years, and many students on the winning team had been involved since the beginning of high school.

Students who had worked on supermileage cars before took previous designs and used that information to better this year’s design.

The frame was completely rebuilt with carbon fiber tubing to make it light. The car has a fuel-injection engine, and senior Jon Soli built a modified circuit to work with the engine.

Bosma said the students incorporated a more efficient fuel injector system instead of a carburetor. The car also shut down the pistons once it hit 30 mph and rolled the rest of the way to save on gas, he said.

And the key is to go small with the car. Soli was the only one who drove the car, and it seemed to be made just to fit him as he reclined.

“It can be a model for design for another vehicle,” Soli said.

The design work started with a few students in a small engines class at school in the fall. Each student was required to put in more than 20 hours of work on the car in order to go on the trip to Brainerd.

Soli said he and Evan Guenther must have put in more than 100 hours of work on the car each.

“It was a good learning experience for next year and years to come,” said Trae Swehla. This was his first year participating.

Many students involved said this knowledge could lead to them tinkering on their own cars to improve mileage.

Last year the E-85 car took first place in the competition.

Supermileage cars this year were judged based on an average of the best six runs — a run is considered two laps around a three-mile track. The average speed of the car had to be at least 15 mph and no faster than 30 mph.

“I wish we could have gotten first,” said Soli.

There was a small issue on the second day, he said, with the fuel injectors.

“I think we did well,” said Zach Rinehart. “This being my first year, I learned a lot.”

Winning students were awarded free computer drafting software to further their interest.