Unsprung weight vs. sprung?

[TroyV]

Is there any sort of tangible info that I can get my hands on that quantifies the value of unsprung weight loss over sprung weight loss?


Lets say I can lose 50 pounds of unsprung weight by having lighter wheels and tires. What does that translate to? Does it actually allow a whole bunch of extra torque? If I pulled 50 pounds out of the interior...what does that translate to?

I guess I'm asking if (for the Mustang platform) there is a specific formula or formulas that give more than just an idea of what is to gain by removing weight above the springs and or below...

[TroyV]

For example: I was once told that, all else being equal, for each 100 lbs off the sprung weight of the car, you gain about .1 in the quarter.. I honestly don't know if that's true...it was just what someone told me..

I'm just looking for a guideline like that is for unsprung weight...

[99GrandTouring]

Less unsprung weight will help you achieve greater times, however I don't believe there is a solid formula for figuring it out..
If the suspension (controll arms, etc...) weight less, then thats less mass that has to move/stop/move in an opposite direction, so it can react quicker and hence give better handeling

[Gene Fine]

I did a little digging, and couldn't find any sort of formula to calculate the value of a reduction of unsprung vs. sprung weight.

Most of those comments, like "100lbs off of the car equals .1 in the quarter" are very rough estimates, that can't really be proven. We use to run into all sorts of comments like that in motorcycle racing, but really proper suspension tuning rider/driver skill made it near impossible to really quantify it accurately.

FWIW, Carroll Smith's comments on the ratio of unsprung to sprung weight in "Tune to Win" are as follows:

Personally, I think - but cannot prove - that we have reached the point of diminishing returns in the reduction of unsprung weight and that, while we should always bear it in mind, the potential rewards to be gained by small decreases in this area do not merit the expenditure of large amounts of time and money.

[TroyV]

Thanks Guys..