Sorry for the dumb general question, but what does a higher octane gas do in turbocharged cars?

 

prevents detenation (uncontrolled combustion of fuel)

higher octane gas is less volatile. ('harder' to burn)

 

Octane is just a rating on gasoline that states its volitility level. The higher the octane, the lesser likely that your engine will ping, detonate, or pre-ignite the A/F mixure. Boosted cars need higher octane because of the higher compression and higher heat levels. Without it, the engine can ping or in bad cases, cause damage.

 

and octane ratings are found by using an Anti Knock Index, that shows its resistance to knocking. The higher the octane number the more additives that are used.