In stock form, 800-1000cc engines gain up to 4 horsepower at the wheels from optimum ignition timing. About 6hp is the maximum achievable with fine tuning per cylinder and premium octane fuel. Electronic Throttle models can gain from 10 – 20rwhp. Turbo model gains start at 20hp, then up depending on boost and setup.
Any other horsepower gains is from modified airflow and proper fuel delivery. Or from the removal of factory detuning implementations. Especially when additional engine modifications are added and the ecu holds things back. Gains of 10-15hp can be seen.
Other Sides of Peak Power
Ever feel your machine accelerate real well up to a certain speed and then just die off? Then it takes forever to reach top speed? Or if you open the intake system up more, allowing more air in, rpms just fall flat? Or there is no difference between 3/4 to full throttle? This is detuning happening. (Or torque limiting on ETC models).
Other than peak power numbers, gains can be had above the peak power point at both higher rpm’s and higher speeds. One example is once the restrictions are removed from reprogramming, 8-10hp can be seen from 40mph to 90mph. The machine no longer falls flat. Instead pulls the same from low speed to top speed.
On the lower end, when accelerating off the line and you can’t spin your wheels, spin sideways or wheelie, this is torque limiting at low speeds. Or you add performance parts and your not gaining any power. The electronic throttle just closes more vs the faster the wheel want to turn. Limiting power output. Once properly unleashed, you can spin tires and roost at will. Gain the horsepower your performance parts are capable of. See gains of 10+ hp as the engine revs much quicker reaching peak power. And holds it. No longer will there be a hang up at 4000rpm when you mash the throttle.
Torque Limiting Example