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gone-ot · 10-15-2011, 07:02 PM

...a series of automotive EQUATIONS worth studying:

T = 5252*HP/RPM

HP' = T*RPM/5252

HP" = (AP*CR*VE*CID*RPM)/(5252*150.8)

HP = (T*RPM/5252) = (AP*CR*VE*CID*RPM)/(5252*150.8)

VE = (T*150.8)/(AP*CR*CID)

...where:

T = torque, lb·ft
HP = horsepower
RPM = engine speed
AP = air pressure, psi (~14.7 psi)
CR = compression ratio
CID = engine cubic-inch-displacement
VE = engine volumetric efficiency, %

...use the HP@RPM and T@RPM values for your engine and backsolve for its' VE at those two operating points (remember it's not a constant, but varies with engine load and rpm).

10-15-2011, 07:02 PM	#8 (permalink)
gone-ot ...beats walking... Join Date: Jul 2009 Location: . Posts: 6,190 Thanks: 179 Thanked 1,525 Times in 1,126 Posts	...a series of automotive EQUATIONS worth studying: T = 5252HP/RPM HP' = TRPM/5252 HP" = (APCRVECIDRPM)/(5252150.8) HP = (TRPM/5252) = (APCRVECIDRPM)/(5252150.8) VE = (T150.8)/(APCRCID) ...where: T = torque, lb·ft HP = horsepower RPM = engine speed AP = air pressure, psi (~14.7 psi) CR = compression ratio CID = engine cubic-inch-displacement VE = engine volumetric efficiency, % ...use the HP@RPM and T@RPM values for your engine and backsolve for its' VE at those two operating points (remember it's not a constant, but varies with engine load and rpm). Last edited by gone-ot; 10-15-2011 at 07:15 PM..