Dart 72

Uma das poucas coisas que nunca esquecerei do 2º grau foram as aulas de Física com o Professor Paulo Miguel na Escola 25 de Julho! Lembro-me que me esforçava para terminar as minhas tarefas antes que o restante dos colegas. Assim me sobrava um tempinho para trocar idéias com ele sobre relações de peso X potência, aceleração, velocidade etc... Lembro que a primeira formula que aprendi foi justamente sobre como obter a velocidade em cada marcha e a velocidade máxima. Segue abaixo a formula:

R1 = largura do pneu X altura
Ex: 275 X 60% = 165

R2 = tamanho do aro / 2 X 25.4
Ex: 15 /2 X 25.4 = 190.5

Circunferência do pneu = R1 + R2 X 3,14 X 2 Ex: 165 + 190.5 X 3,14 X 2 = 2,23 metros

circunferência pneu X rpm X 60 / relação de marcha /relação do diferencial
2,23 X 6000 X 60 / 1 / 3.90 = 205,8 km/h


Existem outras formulas complexas, outros calculos para obter-se dados interessantes. Se alguem quiser arriscar-se ai vão as "danadinhas"!!! Espero que possa estar ajudando alguém, mas cuidado pra não fritar os neurônios, não é esse o meu objetivo!!! hehehe... Mas como falei ainda ontem, nada como as maravilhas do mundo moderno!!! O Gustavo Minela da Minela Engines tem tudo isso em um software, sendo assim não precisa calcular nada, é só jogar os numeros pra dentro do programa e buííííí!!!!


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

1/4 mile ET = 1/8 mile ET x 1.5832

1/8 mile ET = 1/4 mile ET / 1.5832



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