Whats the formula to figure out how much air a motor needs at a certain RPM? I remember it had to do with the CC size and RPM with some division, ahhhh I dont remember - anyone?

 

Anyone?

 

Assuming 100 volumetric efficiency, which changes depending on motor type, forced induction, etc, the formula is:

Air required, in liters/minute = (RPM * displacement in liters * (VE/100))/2

*gets out his TI86 for conversions.......*

For CFM conversion, divide answer above by 28.32


Hopefully I didn't forget anything! This gave 257CFM for my B18C1 at 8100 rpm. Good luck.

-Nick

 

for what motor? if it's an H22 I've done quite a bit of research on figuring out the VE % for a Lude.

VE% for a H22 @ 7000 RPM = 102%
VE% for an S2K @ peak HP RPM = 112%

here are some threads I participated in a while back where we discussed some of what you are asking about. A lot of the stuff I was typing down was stuff I learned from reading Maximum Boost and from a few other sites.

https://honda-tech.com/zerothread?id=96443

https://honda-tech.com/zerothread?id=142398