steel or aluminum driveshaft?

[Ed Wright]

I changed from a Strange light weight steel spool to aluminum, lightened ring gear, and aluminum driveshaft. My car is evidently dumb, because I saw zero. Well, actually, I lost first round at the last race I ran at Memphis when it cleaned the right side splines out of the spool on the starting line. About got the tree.

Still have the driveshaft. Steel spool stays in it now, and I don't spend money on lightened ring gears.

[SSDiv6]

I was told a story about Kip Martin (RIP) and his Super Stock Mustang.
Kip ran an Aluminum drive shaft which broke at a race.
I was told he found a steel replacement and his car slowed down a few 10th's and MPH.
As soon as he replaced the steel unit with an Aluminum one, he gained back his ET and MPH.

Also, as I understand, Stephen Johnson replaced his steel unit with Aluminum and also picked up ET and MPH on his Fairline.

[Jim Caughlin]

As they say on television, "Your results may vary". All I can say is that a low HP combinations like mine, particularly spinning the driveshaft up to 9200 RPM at the finishline should be the most likely candidate for improvement and I got zip. For what it's worth, this was a back to back test so I'm pretty confident of my results. Funny thing is that if I was going to start over, I would buy the lightweight parts regardless. I know in my mind that it has got to be better even if the performance results don't show. At the very least, the weight reduction results in less unsprung weight and allows more static ballast over the rearend.

Jim Caughlin
SS 6019

[Ed Wright]

I always A-B-A stuff like the driveshaft at the track, same day. I did not the spool. Spent that money, and the lightened ring gear, figuring it HAD to be worth SOMETHING. But it was less than 5 lbs lighter than the lightened Strange steel spool. Mine only runs 8500 in the lights.
It ran the weather station predictions equally with both spools.

[Mark Ugrich]

I've often wondered if the reason that lightened axles,driveshafts,etc. don't show an increase in performance is because of the short distance we run.In other words if you made the same weight saving modifications to a Bonneville salt flats car, it has a longer period of time to effect the car.Of course they don't measure E.T.and I could be wrong also.

[Ed Wright]

The diameter on the weight difference makes a difference. 5lbs on a spool, or an even smaller diameter driveshaft is all that much change in inertia. Five pounds on a 32" tire, for instance, is a different deal. I have a pair of Goodyear radials, same size as my MTs, but five pounds per tire difference. Hook just as hard. Consistent four hundredths slower than the Mickys. Three of it in 60'. I can't imagine how it could be anything but weight.

I spent money to get six more pounds off a crankshaft during a freshen up also. Saw nothing. A very low hp engine? Maybe.