Lighter wheels = any E.T reduction?

[FED 387]

Gentlemen--- Car Craft Magazine had an article a while back whereby they tested different transmissions and the Horsepower required to turn a transmission. I do not know if these are totally stock trans or were modified in any way, I also do not know if theTorque Convertor was used in these tests. These are THEIR results:

Powerglide---18 HP
Turbo 350-----36 HP
Turbo 400-----44 HP
C-6--------------55-60 HP
C-4--------------28 HP
A904------------25 HP
727--------------45 HP

[Myron Piatek]

Originally Posted by 340Cuda

I guess we have all bought a lot of stuff that was supposed to be good for a tenth and were disappointed.

However a long time ago Paul Forte told us one of his 904 transmissions would be a tenth quicker than the 727 we were running and he was right.

I am guessing about half of that was less static weight and the other half was reduced rotating weight.

I read about the 727/904 difference decades ago. There was an article (maybe in the Direct Connection manuals) where Paul was testing with a few Stock and/or SS cars around the mid-'70s. I remember the difference being stated as .15, with everything else being made as equal as possible. (converter, weight, etc.)

Physics says that any weight reduction will help a race car accelerate faster, even if it's rotating and the same reduced amount replaced with static weight. But any of the small gains can often be masked by some of the many other variables that can't be consistently and minutely controlled.

My theory has always been to try things that "might" help.....as long as there was a certainty that it couldn't hurt.....and you could afford it. Unfortunately, the "afford it" part usually restricts me.

[Myron Piatek]

Originally Posted by FED 387

Gentlemen--- Car Craft Magazine had an article a while back whereby they tested different transmissions and the Horsepower required to turn a transmission. I do not know if these are totally stock trans or were modified in any way, I also do not know if theTorque Convertor was used in these tests. These are THEIR results:

Powerglide---18 HP
Turbo 350-----36 HP
Turbo 400-----44 HP
C-6--------------55-60 HP
C-4--------------28 HP
A904------------25 HP
727--------------45 HP

Somebody also had an interesting comparison of differential efficiency. I don't recall who, but do remember that a Dana 60 and GM 12 bolt were at the top while the Ford 9" was at the bottom. Mopar 8 3/4 was in between, but I don't remember what else was included.

[Dan Fahey]

The Rotational benefit from lighter wheels is minimal.

Losing weight going to a aluminum vs steel wheel is a benefit.

Less Friction from meshing or rolling parts would offer bigger gains.
Or going to a Radial Tire vs Bias.

[Rick Kolber]

Many years ago one of the popular magazines did a drag test using a stock vehicle and comparing the difference in et between stock steel wheels and aluminum racing wheels..weight difference approx. 60lbs and approx. .010 difference in et. More recently on the Hot Rod Network there was a redo of that test but there findings were 80lbs difference which meant .011 and 1mph gain. The whole scenario is if you keep taking rotational weight off here and there it all adds up..the more the better. Again not for someone on a budget. Just my opinion

[Ed Wright]

If the magazine tested wheels on a stock vehicle, they would see more benefit than a race car, due to HP difference.

As for transmissions, my T350 Pro Trans with lower dia & lighter internals (and other things I likely don't know about) is a solid min 5 hun quicker than another well known/professionally built T350 I had.

[Jim Caughlin]

Originally Posted by 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'

Flywheel weight vs wheel weight is a totally different situation. When I reduced the flywheel/clutch weight and dia, I got HUGE results.

Jim

[Tim Kish]

Originally Posted by Jim Caughlin

Flywheel weight vs wheel weight is a totally different situation. When I reduced the flywheel/clutch weight and dia, I got HUGE results.

Jim

Car probably slows down - on the low HP stuff there isn't enough power to get the car moving if the flywheel/clutch is too light, need that inertia to not bog it down....

I'd say my low HP car doesn't repeat well enough to measure gains of a few hundredths, weather and wind move it more than that run to 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

[Chad Fergen]

Originally Posted by RJ Sledge

My old friend Charlie Ford told me over 30 years ago that "If everything I bought that was suppose to pick me up a Tenth or so was true.....I'd be going zero right now!"

Ain't it the truth......lol

RJ

Ha! That is a "Classic" #loveit