S-A Desiqn Brookland Books
slide show image slide show image slide show image slide show image slide show image slide show image slide show image slide show image slide show image slide show image slide show image slide show image slide show image slide show image slide show image

Automotive Performance Calculators

Estimate 1/4 mile E.T from Weight and wheel HP

ET[seconds] = (Weight[lbs] / Wheel_HP) ^ (1 / 3) * 5.825

ET in seconds:

Estimate Maximum HP from Cylinder Head Flow

HorsePower = CFM * 0.2575 * Number_of_Cylinders

HorsePower:

Estimate Wheel HP From Weight and MPH

Wheel_HP = Weight[lbs] * (Trap_Speed[MPH] / 234) ^ 3

Wheel HP:

Estimate Wheel HP From Weight and ET

Wheel_HP = Weight[lbs] * (5.825 / ET) ^ 3

Wheel HP:

Estimate HP from Torque and Engine RPM

HorsePower = Torque[ft*lb] * Engine_RPM / 5252

HorsePower:

Estimate Torque from HP and RPM

Torque[ft*lb] = (5252 * HorsePower) / Engine_RPM

Torque in ft*lb:

Calculate Displacement from Bore and Stroke

Displacement[in^3] = Number_of_Cylinders * 3.14159 *(Bore[inches] / 2) ^ 2 * Stroke[inches]

Displacement in in^3:

Calculate Tire Diameter from P[section width] / [profile] R[diameter]

Diameter[inches] = Section_Width[mm] * Profile[% of Section] / 1270 + Wheel_Diameter[inches]

Diameter in inches:

Find Rear Gear Ratio

Gear_Ratio = (Tire_Diameter[inches] * Engine_RPM) / (Transmission_Ratio * MPH * 336)

Gear Ratio:

Estimate 1/4 mile ET from 1/8 mile ET

Quarter_mile_ET = Eighth_mile_ET * 1.5832

Quarter mile ET:

Calculate Piston Speed

Piston_Speed[ft/min] = Stroke[inches] * RPM / 6

Piston Speed in ft/min:

HP loss based on Elevation

HP_at_Elevation = HP_at_Sea_Level * (1 - Elevation[ft] / 1000 * 0.03)

HP at Elevation:

RPM after Shift

RPM_after_Shift = Shift_to_Ratio / Shift_from_Ratio * RPM_before_Shift

RPM after Shift:

Calculate Maximum Required CFM

Max_CFM = Max_RPM * Displacement[cubic inches] / 3456

Max CFM:

Many Thanks to Aaron Murray for compiling these equations on his site and allowing us to use them.

Advanced Search

Newsletter Sign Up

Your Cart
Got an Idea?

Do you have an idea for a calculator? Let us know!

Submit Idea

Share Your Calculator Idea exit
Related Titles
CarTech Blog
© 2012 CarTech Inc. All Rights Reserved.
Rapid SSL cert