How many HP ?

[miche25]

With 91 octane, can you get more HP at Stage 2 than Stage 1 -- or is it the same?

 

[92683]

comparison to what octane?

but the octane is not hp or less hp. that's the mapping doing that.
mapping structures certain ecu maps to do certain functions. maps can include but not limited to timing advancement or retarding, fueling, etc.

 

[AzteCypher]

By itself, higher octane won't do much. Higher stage tunes usually require higher octane so as to prevent detonation while increasing the HP.