Gear lightening

[Bill Edgeworth]

Originally Posted by Jeff Lee

I have a dana 60 with all the good parts from MW; MW disk brakes, 40 spline gun-drilled axles, back-cut ring gear, CM axle tubes. What I do not have is an aluminum spool. I have a MW lightened steel spool. So for all my light parts that was one area I did not want to push. The bonus is every time a change a R&P for ratio it always looks new.
I'm still of the opinion these light parts are worth it however I have no back-to-back data to prove it.
I am looking at going from a 168 tooth flywheel to a 142 tooth flywheel. I guess that falls into that "center of inertia" theory Bill was talking about. From what I have read and heard, it will be worth the effort.
I hope...

I think the aluminum spools are real source of controversy exactly because of your observation of gear condition; is the very small advantage of the aluminum spool negated by the extra friction created by all the distortion that takes place with an aluminum spool?
I guess if someone really wants that extra 0.005 they can drop a few grand on a titanium spool.

I think your flywheel will be money well spent; it is any time you can lighten things up prior to any gear reduction. One of the other factors is that the flywheel gets accelerated 4 times in your stick car the spool only once. You should see it in your 60’ it’s a diminishing return thing through the gears. It takes way more energy to accelerate a part at 2000 rpm/second in first gear than at 600 rpm/second down track. It will be a little different animal though. With the same clutch setting your motor will pull down faster due to the reduction in rotating inertia.

I think even the tech department at NHRA has clued in on the center of inertia thing. I noticed with all the recent crankshaft chatter the rules state you can only add enough heavy metal to do a normal balance job. Not sure if that’s exactly how they worded it.
But if you were to turn a bunch of weight off of your crank counterweights and then add heavy metal to get the assembly to balance it’s going to be a faster piece. It won’t show up on the dyno but the motor will accelerate quicker.