Cubic Feet Per Minute (CFM)

[Slymanrs2]

How do you work out the CFM for the following engine?

4.6 Litre V8 (278 cu in)
94mm bore
82mm stroke
5,500rpm (6000rpm MAX)

[sierra1off]

The volume of the 8 cylinders is 278 cubic inches, which takes 2 revolutions to pass through.
So 1 revolution passes 139 cu. in.
at 5500rmp it flows 76450 cu.in
convert this to cfm (/ by 1728 ) = 442cfm.
This assumes a perfect flowing intake, head, and exhaust To be realistic you reduce the cfm by 15% to allow for all the restrictions (or less if its forced induction)
So 442 x .85= 375 cfm maximum flow

Suprising isnt it that we dont need those big Holleys