# Supercharger Cfm

safe supercharger cfm = __(162)(3.14)(stroke)(bore ÷ 2)__^{2}

compression

Pictured is a supercharger with 2 carburetors and the air intake on top.

## What you do:

Calculate the super charger cfm (cubic feet per minute or ft^{3}/min)
your engine can handle.

Factors to consider:

^{2})
and determined by how many cfm the supercharger is pushing in compared to how many
cfm the engine would normally draw in.

maximum supercharger boost in psi = __14.7 psi x supercharger cfm__

engine cfm

Engine cfm is typically between 500 - 1500. The algorithm to accurately calculate engine cfm is long, so see factor 2 (below) to get an easier set of equations to use.

First, calculate the cubic inches of the cylinder when the piston is at tdc (top dead center). The term tdc means the piston is at the top of its travel.

cubic inches at tdc = __(3.14)(stroke)(bore / 2)__^{2}

compression

heat factor = __ supercharger cfm __

cubic inches at tdc

If heat factor > 162, your supercharger is beginning to produce significant heat. You can still increase the supercharger cfm past this point, but you will soon begin to lose horsepower. The equation below puts it all together.

safe supercharger cfm = __(162)(3.14)(stroke)(bore / 2)__^{2}

compression

supercharger weight = __supercharger cfm__ + 50

10

Supercharger weight includes the belt, pulleys and intake pieces, such as spacers.

A supercharger is driven by the crank, so its cfm is related to rpm (revolutions per minute). There is no lag in boost, like a turbo would have.

Definitions:

cfm = cubic feet per minute = ft

^{3}/min

psi = pounds per square inch = lbs/in

^{2}

rpm = revolutions per minute