The easiest trick to extract more power out of your modified motor seems to be to use higher octane fuel. You don’t have to change any mechanical bits, just drive up to a different pump and fill up with whatever has “super” or “power” in its name.
For instance, in this lightly fettled Ford Fiesta ST that was built by Cobb Tuning for The Smoking Tire, it really adds a lot of power. You wouldn’t think changing the fuel would have this dramatic an effect, but dynos don’t lie.
With regular 91 fuel, the Fiesta was rated at 217 hp (at the wheels), but with 100 octane that was bumped up to 240 hp – 23 hp more. Torque went up proportionally too.
Check out the video below if you want to build up your Fiesta ST – it contains quite useful information.