Velocity Rules

Meat talk....Wheel talk.

Moderator: hemingray

User avatar
Ken
Site Admin
Posts: 7501
Joined: Wed Jan 07, 2004 4:23 pm
Location: Auburn, CA
Contact:

Velocity Rules

Postby Ken » Fri Jul 21, 2006 4:53 pm

I found the exact article from my NASCAR book. It's called Chassis Engineering by Herb Adams. More than you'd ever want to know about how to get a car to turn.

This would have some impact on tires/weight...so it's worth reading.


Velocity is equal to Acceleration multiplied by time. If you assume constant acceleration for a period of 5 seconds, you could tell how fast a car was going.

Example: Starting Speed: 64MPH @ 4000rpm's

Velocity = A x T

Velocity =
.444g's x 32.2ft x 5 sec x 60 mph sec
(divided) -------------------------------------------
g's x sec(squared) x 88 ft

Velocity change - 48.74 mph

Velocity at end of straight after 5 seconds = 112.74 mph



If you reduce the weight of the car by 15lbs (.5%) the same engine output would allow acceleration of .446g's


The speed at the end of 5 seconds = 112.95 which is a .21 mph improvement factor of 1.


All rotating parts in the chassis have inertia, which resists angular acceleration. These parts include Tires, Wheels, Brake rotors, hubs, bearings, ring gear, differential.

This time, we reduce the weight of these parts by 15lbs.

Under the same conditions, end speed is: 113.34 or a .60 mph improvement. This shows that a 15 lb. reduction in rotating inertia of rotating chassis parts will have a 3x benefit.



Driveline Rotating inertia. The rotating parts include, crankshaft, flywheel, clutch, transmission gears, driveshaft. Since they run at higher RPM's, the effect of rotating inertia is greater.

Reduce the weight of these parts by 15 lbs.

Under the same conditions, end speed is: 115.70 or a 3 mph improvement. This shows that a 15 lb. reduction in rotating inertia of rotating driveline parts will have a 15x benefits.


Here's the breakdown:

Image
The last words spoken before a YouTube video is filmed: "Hold my beer, now watch this..."

Regards,
Ken Hower
RTF Director
http://www.rubicontrail.org/

Who is online

Users browsing this forum: No registered users and 39 guests