Some formulas contain notation such as ^2 which means "squared"
or ^3 which means "cubed"
**Formulas for Calculating Performance**

Convert between 1/4 mile and 1/8 mile ET's

1/4 mile ET = 1/8 mile ET x 1.5832 (thanks to Bobby
Mosher for this formula)

1/8 mile ET = 1/4 mile ET / 1.5832 (thanks to Bobby
Mosher for this formula)

Calculate 1/4 mile ET and MPH from HP and Weight

ET = ((Weight / HP)^.333) * 5.825

MPH = ((HP / Weight)^.333) * 234

Calculate HP From ET and Weight

HP = (Weight / ((ET/5.825)^3))

Calculate HP From MPH and Weight

HP = (((MPH / 234)^3) * Weight)

**Formulas for displacement, bore and stroke**

pi/4 = 0.7853982

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 = actual cfm / theoretical cfm x 100

street carb cfm = rpm x displacement / 3456 x 0.85

racing 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

driveshaft torque = flywheel torque x transmission ratio

**Formula for instrument error**

actual mph = 3600 / seconds per mile

speedometer error percent = difference between actual and indicated speed
/ actual speed x 100

indicated distance = odometer reading at finish - odometer reading at
start

odometer 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**

cj 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

Many of these calculations have working examples on Car
Math Calculators. Formula's located on the web site: http://www.prestage.com