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Carburetor CFM Calculator

This calculator requires the use of Javascript enabled and capable browsers. This calculator is designed to give the engine's air intake volume requirements. Enter the designation of displacement, 1 for cubic inches or 2 for cubic centimeters. Enter the engine displacement size for the designation. Enter the anticipated maximum safe engine RPMs, typically known as red line. Enter the volumetric efficiency of the engine. (Most factory engines are a compromise between economy, efficiency, reliability and performance; about 80% at red line. Engines that have been tuned for improved performance or have a stronger performance camshaft and valve combination may have up to 92%. A competition roller cam and valve combination may yield 95% while blowers often achieve up to 115%.) Click on Calculate to finalize the calculation; values are updated subsequent to each field change. The value will be returned in Cubic Feet Per Minute required in both the current and optimum volumetric efficiencies (VE), based on the entry values you have made. The default values are for a typical mid 1960s to 1970s muscle car. To do another, click the Clear Values button and then enter a new value. Calculated accuracy of current Javascript enabled browsers is generally 16 places.

This calculator will show you the requirement at WOT, or at the maximum RPM entered, if your Engine is capable of turning 8000 RPM but you shift at 5800 then use the shift point not the max RPM

Big Stall Convertors, huge gears and very light cars are not part of the Calculation and a competent Carburetor Professional should be consulted.
Call Us at 541-942-5920 for the correct carb for your application.
Required Data Entry
Enter Displacement Type (1=CI 2=CC)   
Enter Engine Displacement Size   CI / CC
Enter Maximum Safe Engine RPM   
Enter Volumetric Efficiency Of Engine   % VE
Calculated Results
Required Carburetor Size In CFM
CFM Required Stock heads average 80- 85% 100% VE
CFM Required User % VE
CFM Required (Rounded) 100% VE
CFM Required (Rounded) User % VE
Version 1.2.2

Helpful links:

Carburetor size and series charts



For more calculators go to : http://www.csgnetwork.com/converters.html



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