Owners can find the right carburetor parts for their vehicles by calculating the carburetor size that their vehicles need for optimum performance. The standard formula for gasoline engines is engine size in cubic inches multiplied by maximum RPMs and divided by 3,456. This calculates the carburetor's necessary cubic feet per minute capacity at 100-percent volumetric efficiency.
Owners can also use an online calculator to determine carburetor size. GTSparkPlugs has one on its website. Owners enter the engine size, maximum RPMs and volumetric efficiency. They then select if the carburetor is stock or modified. Owners looking for manufacturer-standard carburetors select the stock option, and they select the modified option if looking for race-ready carburetors. Clicking the Calculate button produces charts of carburetor data, and owners can click specific parts of the charts for more information.
Carburetors blend air and fuel in internal combustion engines and allow air to enter the engine's intake manifold. Carburetors are open pipes that start wide, then narrow, and widen again in a Venturi. This makes the air flow faster in the narrow part. Basic carburetors have one Venturi, and more complex carburetors have multiple Venturi. The throttle valve controls the airflow, which then regulates the engine's power and speed, and the vehicle's accelerator pedal usually controls the throttle valve.