What Is A Carburetor?
A carburetor is an engine component that sits on top of the intake manifold and controls the amount of fuel and air that enters the engine, helping it run. It maintains engine speed from driver input to the throttle blades via a cable and gas / accelerator pedal. It is important to choose a carburetor for your specific car or truck application. JEGS has many carburetors for sale to match your vehicle application and use.
What Is The Function Of A Carburetor?
The main function of the carburetor is to control engine speed from driver input to the throttle. It does this by controlling the amount of fuel and air that enters the engine. In addition, it meters fuel and air to transition from idle to part throttle and to wide open throttle smoothly.
What Is CFM On A Carburetor?
CFM, which stands for “cubic feet per minute” is the amount of air that can enter the throttle bores of the carburetor. The correct carburetor CFM size is based on the engine size, the maximum rpm the engine will be used at, and the main purpose of the vehicle, whether street or race use. The formula to calculate CFM size is (engine) cubic inches x (max engine) RPM x volumetric efficiency. Volumetric efficiency is the actual amount of air flowing into an engine vs the maximum it could flow based on calculation, shown as a percentage. As is it not easy to know exactly what your engine's VE percentage is, you will need to make an educated guess. We advise that your guess be "conservative" and realistic for the calculation. Most street engines have a volumetric efficiency of around 85%. A VE of 95% is considered extremely well-flowing. A highly-developed match of the intake passages, combustion chambers, exhaust passages, and valves through planning, machine work, and testing can put an engine at 100%-110%, such as in NHRA Top Fuel, Funny Car, and Pro Stock applications. Bigger is not always better as too big of a carburetor will hurt performance just as much as too small of a carburetor. Once you come up with the answer to the first part of the equation, it is then divided by “3456”. This is the number of cubic inches in a cubic foot (1728) times the number of revolutions (2) for a 4-stroke engine to fill and empty all of its cylinders. For example, a 350 CID engine with a max rpm of 6000 and an estimated volumetric efficiency of 85% is calculated as 350 x 6000 x .85 = 1,785,000, which is then divided by 3456. The answer is 516.49. The closest carburetor cfm available to that answer is your ideal carb size. If the engine will primarily be used on the street, a 500 CFM carb in this example would be ideal. If the engine will primarily be used for racing, a 550 CFM carburetor would be acceptable.
Below is a calculator to make it easy to select or confirm the correct carburetor CFM size:
Carburetor CFM Calculator
What Is The Best Way To Clean A Carburetor?
The best way to clean a carburetor is by using a brush to remove corrosion and buildup from the exterior and then spraying it with carburetor cleaner. This will remove most of the gunk from the outside of the carb. If you want to clean the inside of the carburetor, carefully take it apart, noting all of the pieces and the order they were removed to make reassembly easier. You can then use a brush and carburetor cleaner to clean the internal parts as needed.
What Is A Good Carburetor Cleaner?
For many people, the best type of carb cleaner is the aerosol version which helps to clean hard-to-reach areas. JEGS offers carb cleaners to keep your carb looking good and help prevent it from gumming up. Having a straw included with the can of cleaner is a plus, or getting one to fit the nozzle if the cleaner doesn’t include it can help.
What Is In A Carburetor Rebuild Kit?
A carburetor rebuild kit typically includes all of the replaceable seals and gaskets needed to renew the carburetor performance and keep it leak-free. It can also include a power valve (for Holley applications), accelerator pump diaphragm, needle and seat, and additional components depending on the design of the carburetor (such as Edelbrock or Holley brands) and the kit.
