Methanol

Methanol was pioneered by the Nazi era Germans to increase power in boosted internal combustion engines.  This enables less fuel trim, more advanceded timing, and higher compression without detonation.  These can also “clean” the engine.  They pose a slight risk of hydrolock with a stuck injector.

Most people will gain power without a specific tune, but with a specific tune and a tuner willing to push it is possible to unlock massive gains like the German’s did often exceeding 35%.