Lighter wheels = any E.T reduction?

[nhramnl]

I tend to agree with Jim. Remember that most of the super-trick, gun-drilled, unobtanium stuff was designed for Pro Stock (and maybe Comp), where getting the entire car to a crazy light weight was the challenge. I honestly think that today, it's mostly for the coolness factor.

[ss3011]

Originally Posted by nhramnl

I tend to agree with Jim. Remember that most of the super-trick, gun-drilled, unobtanium stuff was designed for Pro Stock (and maybe Comp), where getting the entire car to a crazy light weight was the challenge. I honestly think that today, it's mostly for the coolness factor.

Interesting idea , but I don't agree with Jim . I believe the lightweight stuff does work for all weights of cars , but the faster the acceleration rate, the more important lower inertia parts are . Higher horsepower cars accelerate quicker , so for them its more important . Also the farther that lightweight part is from the engine the less effect it has on hp it takes to spin it up . Another point is a tire is only spun up from zero to maybe 1600 rpm in say 9 secs , a driveshaft from zero to 8000 rpm , and an engine spins up several times , depending on how many gears you have in the trans . So if I were to prioritize what things to concentrate on reducing mass just for pure acceleration it would be the engine , then the tires , followed by the wheels , and finally the driveshaft . There are other reasons for lightening up stuff like overall weight , ease of doing , or expense . If we all had unlimited funds , we would do all the above .

[Bobby DiDomenico]

Originally Posted by ss3011

"Interesting idea , but I don't agree with Jim." "If we all had unlimited funds , we would do all the above .

Yep, lighter, stronger always better! Return on investment in this case? Like you I'm spending that $600 or more on engine/trans.
I wouldn't spend it on slightly lighter than light wheels. I still agree with Jim, for the results save the money if you are on a budget.

[FED 387]

You would be surprised at how many revs a tire actually turns from the time it leaves the starting line until it goes a 1/4 mile. Actually About 150 to maybe 175 times depending on if you have smaller or larger diameter tires. The same with engine maybe 1200 actual revolutions on an engine turning 7200 rpm in a 10.5 second run

[voltdr]

Because we can't test in a "vacuum", our test results are subject to interpretation based on any differences in track surface, track temps, wind direction changes, and any other number of variables. I do believe that if you apply all of the things that are supposed to be better, then it will be better. You just may or may not see the results immediately.
It's the same in my electrical business, I can guarantee that you will use less electricity by switching to a more efficient electric motor or LED lights, but you might not see a difference in your electric bill due to differences in running time of all of the components are different each month.
Dan

[nhramnl]

Originally Posted by ss3011

Interesting idea , but I don't agree with Jim . I believe the lightweight stuff does work for all weights of cars , but the faster the acceleration rate, the more important lower inertia parts are . Higher horsepower cars accelerate quicker , so for them its more important . Also the farther that lightweight part is from the engine the less effect it has on hp it takes to spin it up . Another point is a tire is only spun up from zero to maybe 1600 rpm in say 9 secs , a driveshaft from zero to 8000 rpm , and an engine spins up several times , depending on how many gears you have in the trans . So if I were to prioritize what things to concentrate on reducing mass just for pure acceleration it would be the engine , then the tires , followed by the wheels , and finally the driveshaft . There are other reasons for lightening up stuff like overall weight , ease of doing , or expense . If we all had unlimited funds , we would do all the above .

I think we're saying the same thing, just differently. As another poster suggested, if I'm choosing between gun-drilled, 40-spline axles, an aluminum spool and a lightened ring and pinion, I would probably save the money and put it in the engine. Reducing unsprung mass does allow quicker acceleration of the component in question, but the question becomes "At what price for what gain?"

[The Hawk]

I`d have to agree with Jim on this as well. I`ve done back to back runs with steel wheels and Centerlines with the same size tire and saw no noticeable improvement on a V/SA Buick Skyhawk or Skylark.

[Ed Wright]

I went from four Stock steel wheels to four light aluminum wheels on my '56 Chevy Jr Stocker, and was disappointed to find zero change in ET or MPH.

Same results from going to an aluminum spool, lightened ring gear & drilled axles on my C/MP '69 Camaro a few years later. I have wasted a lot (to me) of money testing "trick" parts over the years.

[Bob Mulry]

The further away from the centerline of rotation the greater benefit of rotating weight reduction..

Remove 1 pound of rotating weight from the OD of the flywheel vs. a 1 pound reduction from gun drilled axles.....

It's called moment of inertia.

Just sayin'

[Wayne Scraba]

I maybe shouldn't wade in here because I really don't have a dog in the fight, but on the other hand, perhaps this info can help someone:

Decades ago, when I worked for the late great Super Stock & Drag Illustrated, I penned a tech article on the effects of reducing wheel weight. Sheldon Gecker (most here know of Sheldon) had run some well documented A-B-A tests of wheel weight on his Super Gas car. He went as far as having some heavy wheels made (same configuration as his light wheels), ran them and then switched to lighter wheels and then back to heavy wheels. The car definitely picked up with the light wheels. Keep in mind this was a relatively light, relatively high horsepower car. If I recall correctly, the goal was to improve the vehicle reaction and short times. Obviously for Sheldon, it worked.

On a similar note, shortly after that I was personally involved in another magazine driveshaft test on a very well sorted, consistent mid to high class NHRA Stock Eliminator car. I won't mention the racer's name, but he is smart, seasoned and meticulous. A stock DOM shaft was swapped for a lightweight (illegal of course...L-O-L) aluminum shaft and then back to the DOM shaft (typical A-B-A test). Conditions were monitored closely and it was all accomplished in a short period of time. The car definitely picked up with the light shaft.

My take by looking at the comments here is that the power and weight of the car can make a considerable difference. As a result, your results may vary...L-O-L