Custom Tunes.

[Jackpine]

Lars said it correctly, Levi.

I want to add a couple of things though.

1. Don't ever request a tune for octane ratings that are higher than the gasoline you have available - you would NOT want a custom 93 octane tune.

2. If you travel to a place in the US that has higher elevation, you are likely to find all octane ratings reduced, as Lars stated about the Black Hills. That's because altitude improves the anti-knock properties of gas. So, if you were to travel to the Black Hills, you could safely run 91 octane with your custom 92 octane tune. (And, you should not have to adjust the timing). I use 85 octane gas when we go to Colorado with my 87 octane tunes.

- Jack