Banjo-Kazooie Wiki
The Test-O-Track is an area introduced in Banjo-Kazooie: Nuts & Bolts that allows players to test custom built vehicles before saving them and using them in the games stages. It is located in Mumbo's Motors in Showdown Town. It features various areas including a pool, a steep slope, aerial testing tracks, and ice to test a vehicle's compatability with each feature. Some of the other attractions include a loop-de-loop, a rocky ground area resembling rough terrain, a snake tunnel (which will do quite some damage if you go in loops if your vehicle wasn't built right), a raised level where most of the ramps go to (and above this area the aerial testing tracks can be found), a ring area above the rough terrain which grows and shrinks in certain set places, and a main field where the player starts out at with land vehicles. Here a soccer ball can be found (a second can be seen floating in midair. Also, in this mode, the Speedometer isn't visible.
The Test-O-Track has no missions or characters featured during normal gameplay, however, by downloading L.O.G.'s Lost Challenges, the player can add various missions to the area for more Jiggies and Achievements.