Formula for air required @ RPM ?

sparq · #1 03-03-2003, 09:14 AM

Alright, I tried searching but I couldnt think of anything that would bring it up. Im looking for the forumla where you put in displacement, then you times it by RPM and do whatever - whatever, and you come up with how much air you need for the motor.

Also, does this work even if the numbers im looking for are CC and not liters? Like on a 150cc scooter motor?

Twist · #2 03-03-2003, 10:52 AM

I'm pretty certain that cc's are the same as mL's. so take CC and multiply by 10^-3 and !boom! liters. For example, a 1500 cc engine would be 1.5 Liters.

sparq · #3 03-03-2003, 10:54 AM

Yeah but that still doesnt get me the formula...

Twist · #4 03-03-2003, 11:03 AM

Sorry. I can't help you there besides www.google.com .

or maybe one of the formulas here: http://www.rpmoutlet.com/formula.htm

J SPEC SilEighty · #5 03-03-2003, 11:06 AM

((Displacement in liters * 6.10237) * RPM * 1/2 * Volumetric Efficiency) / 1728 = airflow in CFM

CFM * .756 = airflow in lb/min

for volumetric efficiency if you dont know the actual number then you can just use something around .85 for that number

speediva · #6 03-03-2003, 11:17 AM

Conversion factor: 1mL = 1cm^3

Therefore 1000mL = 1L = 1000cm^3

Oh, and cc = cm^3 (Cubic Centimeters)

sparq · #7 03-03-2003, 11:44 AM

Damn it im screwed... 150cc @ 11,000 rpms :o

YellowMaranello · #8 03-03-2003, 01:09 PM

I'm just curious, but is this inspired by the scooter thread?

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