: I am aware of many instances where cars have gained 75 HP or more by freezing the IC alone, nothing more. IMHO, this is not a real-world number. greg(dallas) did it on his last dyno session with his sport 600s and he saw either a 7 or 17 rwhp gain. It certainly wasn't 'significant' (disclaimer: he was having HP problems due to shitty fuel filters dramatically affecting fuel delivery.)