Saturdays of Thunder

"Saturdays of Thunder" is the ninth episode of the The Simpsons' third season. The episode aired on November 14, 1991.

Synopsis
When the local Soap Box Derby is held in Springfield, Bart has his heart set on first prize. But the catch is that he must build his own Soap Box Racer. In the meantime, after taking a fatherhood quiz, Homer discovers he knows next to nothing about his son. He offers to help his son by building him one as a surprise. Unfortunately, Homer's less than adept building skills brings Bart a very shoddy, rickety piece of junk for a racer (named Li'l Lightnin'). This is especially so in comparison to Martin Prince's personally designed and built space shuttle-like racer, Honor Roller. Unable to gather the courage to tell his father that his racer is terrible, Bart initially attempts to use it in the preliminary match...where he and Martin form an alliance vowing that either must somehow beat bully Nelson Muntz and his very intimidating racer, the Roadkill 2000, armed with every dirty trick in the book.

When the race is underway, Bart can barely reach any kind of noticeable speed with Homer's racer, which eventually falls apart. Meanwhile, Martin has difficulty controlling his racer, as it is moving too fast, which eventually causes him to crash. After being injured, Martin finds that he can no longer race and opts for Bart and himself to combine forces by having Bart race Martin's racer over the racer he and Homer built. Bart seeing no other way to win agrees, which breaks Homer's heart. When Bart later apologizes and desires Homer's best wishes, Homer selfishly denounces both Bart and Martin telling Bart to do whatever he wants. Dejected, Bart gets ready to race in the final match with Martin's newly tuned racer. As he does this, Homer thinks to himself about how selfish he's been, realizing he has learnt a lot about his son, and that Bart needs his support regardless of whose racer he's using and he rushes off to the race. At the starting line, Homer wishes Bart luck and tells him that no matter how the race ends he'll still be proud of him. The race is tough as Nelson pulls every dirty trick in his arsenal, but eventually through his skill Bart comes out on top and the "team" enjoy their victory.