MAF

[Greg Hermann]

><snip>
>>170 Gm/sec works out to 300 cfm (and about 205 HP) (at sea level), which
>>works out to 84% or so VE--
>
>Could you elaborate on the math??
>
>Thanks

454 grams = 1 lb. (conversion constant)
.075 lbs./cubic foot = typical sea level density of air at a reasonable
temperature

(1) therefore 170 grams per second /454 grams/ lb. = .374 lbs./sec

(2) therefore, .374 lbs./sec. x 60 seconds/minute  = 22.47 lbs./min. (of
air, number used in (3) & (4) below)

(3) therefore 22.47 lb/min. / .075 lbs./cubic ft. = 299.6 cubic feet/min.
(cfm) of air.

(4) therefore, 22.47 lbs./ min. x 60 min/hour = 1348 lbs/hour of air.

(5) therefore 1348 lbs./ hour / 13.5 (typical WOT a/f ratio for an NA
engine) =  99.87 lbs./hour of fuel

(6) therefore 99.87 lbs./ hour of fuel/ .48 lbs. fuel/ brake horsepower
hour ( a pretty typical brake specific fuel consumption figure for an NA
engine) = 208 Horsepower.

(NA = naturally aspirated)

Regards, Greg