Tuesday

The Car, It's a Drag


The Car, It's a Drag
By Don Terrill (c) - www.RacingSecrets.com

We focus on making more power, but we should also look at what's keeping the power from becoming speed.

Frictional Losses caused by Tires:

Rolling Friction = Cr * M * G
Cr = coefficient of rolling resistance
M = total mass of the vehicle with driver
G = acceleration due to gravity

As you can see by the formula, we want a lighter car and tires with a lower coefficient of rolling resistance.

Tire Type & Coefficient of Rolling Resistance:

Train wheel, 0.001
Low rolling resistance car tire, 0.006 - 0.01
Ordinary car tire, 0.015
Racing tire, > 0.015

Look to Bicycle racing for how to lower tire friction, but be careful to not lose needed traction - a fine line.

Other (non engine) frictional losses:

Transmission
Rear End
U-Joints
Wheel Bearings

These losses are mainly from fluid and seals. How can you improve?

Aerodynamic Losses (Drag):

Drag = Cd * A * .5 * r * V^2

Cd = drag coefficient
A = frontal area
r = density of the air
V = velocity

As you can see by the formula, we want a lower drag coefficient and a smaller frontal area.

Look to HPV and Salt Flat racing for how to lower aerodynamic drag.

photo by: djshoserhookednet

Want to send off a nasty email about how wrong I am? Well, first read this and then write your own article.