(CNN) -- Seven-year-old Timmy "Mini" Tyrrell gets a high-five as he steps out of his go-kart at the King George Speedway in King George, Virginia.
"Good job, Mini," says another racer.
Dressed in a red fire suit and standing just under 4 feet tall, Timmy has been racing go-karts for fun since he was 4 years old.
Now he races for a greater cause, to raise money for families of children with cancer.
He calls it Mini's Mission.
It all started when his friend Ella Day was diagnosed with a brain tumor.
"We've been friends for a very long time," Timmy said. "I saw that something was wrong, and I wanted to help her."
"We had long conversations about what would happen, how she would lose her hair," said his mother, Tina Tyrrell. "And he said, 'Dad, I want to raise money for kids with cancer. And I need you to help me.'"
So he turned to what he loves most, racing go-karts.
At the races, Timmy collects donations for the Jeffrey Virostek Fund to help families with children with disease.
Tasha Virostek started the fund after her son Jeffrey died of leukemia at age 4.
"The journey is not just the cancer. It takes an emotional and a financial toll," Virostek said. "We give grants to organizations that directly help families who are going through this journey."
Timmy's friend Ella is cancer-free after undergoing six months of radiation and chemotherapy.
"She's doing great," said her mother, Karen Day. "When I heard what Timmy was doing, I thought it was incredible. Families need help. They go through so much ... it's an expense that you couldn't imagine."
Now 8 years old, Ella is one of Timmy's biggest fans.
"It makes me feel really happy because he wants to help other kids with cancer," she said.
Timmy races every Saturday from March to December at the King George Speedway. In less than a year, he has raised more than $22,000 for the cause.
He doesn't plan to slow down any time soon.
"I wanna do this forever until I'm racing in big cars," Timmy said.
"For any child to have that compassion and that understanding and to want to make a difference, as a mother, how proud can you be?" said Tina Tyrrell.
For Timmy, racing is about more than just winning or losing.
"I'm thinking about helping children, thinking about racing my go-kart, thinking how much fun it is, and thinking about how much children I can help and families."
How to help
One-hundred percent of the money raised goes directly to helping families of children with cancer.