is this right? (math involved) - The 1947 - Present Chevrolet & GMC Truck Message Board Network

magnethead · 10-14-2006, 12:37 PM

I have a 454 CID motor.

It is a 4 stroke, so it takes 2 rotations to make a power stroke.

therefore, it moves 454 cubic inches of air per 2 revolutions, correct?

454 cubic inches is 0.26 cubic feet.

My tach indicates 2800 RPM or so going 60 MPH.

That's 1400 power strokes per minute, correct?

therefore, wouldn't cubic feet times the amount of times that much air is moved per minute give us CFM?

1400 times 0.26 = 364 CFM.

Does that not mean a 375 CFM carburetor would be about right for my motor? (this is all hypothetical, i'd imagine there's losses in there somewhere?)

then why do I have a 650 CFM carburetor from the factory? Did i make a bad calculation or assumption?

10-14-2006, 12:37 PM	#1
magnethead 7000 #'s of american IRON Join Date: Dec 2004 Location: north tx Posts: 883	is this right? (math involved) I have a 454 CID motor. It is a 4 stroke, so it takes 2 rotations to make a power stroke. therefore, it moves 454 cubic inches of air per 2 revolutions, correct? 454 cubic inches is 0.26 cubic feet. My tach indicates 2800 RPM or so going 60 MPH. That's 1400 power strokes per minute, correct? therefore, wouldn't cubic feet times the amount of times that much air is moved per minute give us CFM? 1400 times 0.26 = 364 CFM. Does that not mean a 375 CFM carburetor would be about right for my motor? (this is all hypothetical, i'd imagine there's losses in there somewhere?) then why do I have a 650 CFM carburetor from the factory? Did i make a bad calculation or assumption?



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.