CFM output for M90

Matt SC ESC

Registered User
does anyone know what the stock m90, with the stock pulley, puts out CFM-wise at idle? roughly 850-950 rpm. Also, does anyone know the formula to calculate required CFM on a n/a engine?
 
M90= 90ci (I would assume that is per revolution) So take that times rpm times the drive ratio divided by 12^3 to convert to ft^3.

I don't know if that is much of a start or not. :rolleyes:

I would guess around 100 cfm.
^^
From (850/5200)*13000*90/12^3
 
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If the M90 means 90 cubic inches displacement per revoulution, I come up with 270.8 CFM at 5200, not 100 CFM....

90 * 5200 = 468000 = cubic inches per minute at 5200 RPM

12 * 12 * 12 = 1728 = number of cubic inches in a cubic foot

468000 / 1728 = 270.833 = number of cubic feet per minute at 5200 RPM.

I'm not sure that M90 means 90 in^3 per revoultion, but it may.
 
Doesn't the blower spin at 15,000rpm? due to the jacshaft, ect. Its not spinning at the same speed as the motor. Maybe something else to look at.
 
The figures I have heard are ~500 CFM. But this is at rated boost,
which is around 12# at the hat. It is rated with a system similar
to the one that turbos use, CFM @ rated boost. You can also
kind of convert it to CFM @ atmospheric, by converting boost
to bars of pressure, 12# would be like 1.8 bar absolute and
then the 500 CFM is multiplied by 1.8 to get CFM @ atmospheric
pressure, which is ~900 CFM. Your inlet tubing and MAF should
be able to flow 900 CFM to properly feed the beast.
 
figured out all the numbers, but now i need to calculate how im going to keep it below about 6-7lbs of boost. Its going on a 5.0L f150. im hoping i dont have to run a 12 inch pulley, to accomodate less boost.
 
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