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And, here are a few Automotive
Formulas!
Formulas for
displacement, bore and stroke:
cylinder volume = pi/4 x
bore^2 x stroke
stroke = displacement /
(pi/4 x bore^2 x number of cylinders)
Formulas for
compression ratio:
(CylVolume + ChamberVolume)
/ ChamberVolume
cylinder volume = pi/4 x
bore^2 x stroke
chamber volume = cylinder
volume / compression ratio - 1.0
displacement ratio =
cylinder volume / chamber volume
amount to mill = (new disp.
ratio - old disp. ratio / new disp. ratio x old disp. ratio) x stroke
Formulas for
piston speed:
piston speed in fpm = stroke
in inches x rpm / 6
rpm = piston speed in fpm x
6 / stroke in inches
Formulas for
brake horsepower:
horsepower = rpm x torque /
5252
torque = 5252 x horsepower /
rpm
brake specific fuel
consumption = fuel pounds per hour / brake horsepower
bhp loss = elevation in feet
/ 1000 x 0.03 x bhp at sea level
Formulas for_indicated horsepower & torque:
horsepower = mep x
displcement x rpm / 792,00
torque = mep x displacement
/ 150.8
mep = hp x 792,000 /
displacement x rpm
mep = hp x 792,000 /
displacement x rpm
mechanical efficiency =
brake output / indocated output x 100
friction output = indicated
output - brake output
taxable horsepower = bore2 x
cylinders / 2.5
Formulas for air
capacity & volumetric efficiency:
theoretical cfm = rpm x
displacement / 3456
volumetric efficiency =
acutal cfm / theoretical cfm x 100
street carb cfm = rpm x
displacement / 3456 x 0.85
racin carb cfm = rpm x
displacement / 3456 x 1.1
Formulas for tire
size & their effect:
effective ratio = (old tire
diameter / new tire diameter) x original ratio
actual mph = (new tire
diameter / old tire diameter) x actual mph
Formulas for g
force & weight transfer:
drive wheel torque =
flywheel torque x first gear x final drive x 0.85
wheel thrust = drive wheel
torque / rolling radius
g = wheel thrust / weight
weight transfer = weight x
cg height / wheelbase x g
lateral acceleration = 1.227
x raduis / time^2
lateral weight transfer =
weight x cg height / wheel track x g
centrufugal force = weight x
g
Formulas for
shift points:
rpm after shift = ratio
shift into / ratio shift from x rpm before shift
drivehsaft torque = flywheel
torque x transmission ratio
Formula for
instrument error:
actual mph = 3600 / seconds
per mile
speedo error percent =
difference between actual and indicated speed / actual speed x 100
indicated distance =
odometer reading at finish - odometer reading at start
odo error percent =
difference between actual and indicated distances / actual distance x 100
Formulas for MPH
RPM gears & tires:
mph = (rpm x tire diameter)
/ (gear ratio x 336)
rpm = (mph x gear ratio x
336) / tire daimeter
gear ratio = (rpm x tire
diameter) / (mph x 336)
tire diameter = (mph x gear
ratio x 336) / rpm
Formulas for
weight distribution:
percent of weight on wheels
= weight on wheels / overweight x 100
increased weight on wheels =
[ distance of cg from wheels / wheelbase x weight ] + weight
Formulas for
center of gravity:
cg location behind front
wheels = rear wheel weights / overall weight x wheelbase
cg location off-center to
heavy side = track / 2 - [ weight on light side / overall weight ] x track
cg height = [ level
wheelbase x raised wheelbase x added weight on scale / distance raised ] x
overall weight
"Share My"` Formulas
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