The high octane provided by race gas can offer great benefits to racers on both the track and strip, which is why Dodge devised a way to throw the stuff into the Challenger SRT Demon.
By default, the Demon will require unleaded premium gas -- either 91 or 93 octane, depending on location. But for those who choose to drag with race gas of 100 octane or higher, the Demon Crate will include a second powertrain control module. Plug it in, hit the included "race gas" button, and off you go.
With the new bits plugged in, the Demon's V8 can adjust its spark timing to take advantage of the higher-octane fuel. Dodge promises improved elapsed times on the drag strip with race gas. Thankfully, the race-gas module can retard or advance the timing with premium gas in the tank, or a mix of the two. It won't move to the more aggressive timing unless the knock sensors detect a proper amount of race gas.
The higher a fuel's octane number, the more compression it can withstand without detonating. The spark can take longer to ignite the fuel if there are less concerns of it detonating early, which is called engine knock and can seriously damage an engine's internal components. Igniting the spark plugs earlier (aka retarding the spark timing) reduces power output, but it can prevent knock from consuming an engine.
The Demon will finally be shown off at the New York Auto Show next week.