Are you sure that's not talking about rotating weight, like wheels? But even those numbers have been quoted as being anywhere from 3-10x. Depends who you talk to. Just my opinion, but I don't believe there is that much difference between unsprung and sprung weight on a drag car. A 440-6 Challenger racer in Stock tested an 8 3/4 and Dana 60 back-to-back while equalizing the weight difference with ballast. I forgot the actual weight difference, but he didn't see any definite ET difference. However, the Dana 60 is suppose to be more efficient and take a little less HP to turn also.
Unsprung weight would probably make the most difference in a circle track/road race car because the suspension has a lot more work to do than on a drag car. Weight would be a big factor with the constant up-n-down movement of the unsprung wheels, tires and and rear end throughout the course.[/QUO
All I can be certain of is my experience. ( I'm pretty sure wheels are unsprung weight) I took off the super heavy hideous aftermarket wheels my Mustang had on it( saving 14.6 lbs per wheel/tire combo !) & my 1/4 mile times & traps were improved, fuel economy went up by an average of 25-30 miles per tank. No way to be 100% certain, but I would say that braking & cornering improved as well. I'm no expert but I dont think removing 60 lbs of interior/sheetmetal would have the same effect. Again, I'm not trying to start anything, just relaying my experiences.:toothy10: