The high-revving 4.5-liter V8 redesigned pistons increase the Speciale's compression ratio from 12.5:1 to 14.0:1. The efficiency increase it brings is the main reason the engine produces 596 hp, 34 more than the regular 458 Italia's, at the same 9000 rpm.
The shape has been optimized to improve the flame velocity
The pressure in the combustion chamber is increased (+10bar at wide open throttle)
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.