HP and weight question.
Thread Starter
Racer
Joined: Aug 2006
Posts: 261
Likes: 0
From: Virginia Beach VA
HP and weight question.
Is there a rule of thumb that X number of pounds of weight reduction acts the same as X number of horse power increase? And what is the difference between sprung and unsprung weight?
Team Owner
Joined: May 2005
Posts: 23,682
Likes: 9
From: Flagstaff Az.
I think it is about 10-1, not sure. Sprung weight is all weight supported by any type of spring on the car's suspension. Unsprung weight would be the tires, wheels, brakes, and other parts of the suspension that are "under" the springs.
Race Director
Joined: Mar 2007
Posts: 18,308
Likes: 21
From: Marlton. Increasing performance one speeding ticket at a time! NJ
What your looking for is power to weight ratio. There is no set rule, but for our cars its about 10:1 as tiojames mentioned. For example:
Stock: 3200lbs/350hp=9.143lbs/hp.
Take 100lbs off and it becomes: 3100lbs/350hp=8.857lbs/hp.
To get the same weight/hp ratio, you'd have to increase hp to 361hp, or 11hp per 100lb reduction.
That ratio doesn't work for other cars (like a 4400lbs SRT8), or if the weight reduction was too dramatic. But it gives you a ballpark.
Stock: 3200lbs/350hp=9.143lbs/hp.
Take 100lbs off and it becomes: 3100lbs/350hp=8.857lbs/hp.
To get the same weight/hp ratio, you'd have to increase hp to 361hp, or 11hp per 100lb reduction.
That ratio doesn't work for other cars (like a 4400lbs SRT8), or if the weight reduction was too dramatic. But it gives you a ballpark.
Last edited by nj02vette; Jul 3, 2007 at 08:35 AM.
