Haha, fair! 😀
The Turbo options can be found at the very bottom of the options menu that can be accessed through the title menu 😉 but this will change with the next big version where you'll choose the Turbo mode at the beginning of a race - similar to the Mario Kart games.
There you can change a few other options as well, like seasons, touch controls, language, etc...
Turbo is turbo on by default and makes every chair 20% faster. Super and Ultra Turbo makes them 40% and 60% faster, respectively 😉
The bar at the bottom is your energy or stamina. When it runs out, you'll be 20% slower - this can easily happen on standard or hard difficulty and is less important on easy.
There are a few secret codes that unlock additional characters, options and a chair. You can find the codes here:
https://itch.io/jam/igc-testbuddies-001/topic/5754269/chair-champions-secret-codes-