Re: The calculations for supercharging

[bearbvd@domain.elided (Greg Hermann)]

At 2:05 AM 8/4/02, Jon Pike wrote:
>>1 litre is 61.02 cu. inches.  So our motor turning at 3000 rpm will
>>ingest 3051 cu. inches
>>per second, or approx. 183060 cu. inches per minute.

ONLY if it is a TWO stroke with very high volumetric efficiency.

 There are 1728 cu. inches in a cu.
>>ft, therefore the motor ingests 105.93 cfm.  At 6000 rpm  - assuming the
>>same pumping
>>efficiency - the motor ingests twice this amount of air = 211.8 cfm.

More like 105.9 cfm, times about .85 (assumed VE) for a four stroke. Means
90 cfm at 3K rpm, 180 cfm at 6K .
>>
Suggest using the real equation for calculating adiabatic compression of a
gas, and, for a decent centrifugal compressor, an efficiency in the range
of .63 to .70 to figure the HP.

For a Roots, best to work with the VE/AE  vs. speed curves for the
compressor to figure out where you are.

Greg
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