Barrel throttles have an inherent advantage over butterfly throttles in regards to flow and power.
Barrels are suitable for engines running at over 15,000 RPM and must be designed to suit a particular engine type. (Source: Jenvey Dynamics)
With conventional wastegated turbochargers or fixed geometry turbochargers (FGT), a turbine flow area cannot be adjusted during operation.
Knocking is abnormal combustion in which the air-fuel mixture ignites prematurely due to exposure to high temperature and pressure, creating an unwanted high-frequency noise. When the compression ratio is increased, the temperature at compression top dead center (TDC) also rises, increasing the probability of knocking.