Posted By: SCATPK
Aluminum vs Steel Replacement Driveshaft Question - 11/14/09 04:41 AM
I am going to order a new driveshaft Monday from Dynotech and wondering is there any advantage in going with an aluminum one over a steel replacement?
Aluminum vs Steel Replacement Driveshaft Question
Posted By: sixpakdodge
Re: Aluminum vs Steel Replacement Driveshaft Question - 11/14/09 04:47 AM
Less rotating mass in the drive train.
Posted By: polyspheric
Re: Aluminum vs Steel Replacement Driveshaft Question - 11/14/09 03:08 PM
It's an improvement, but it's worth very little. Don't expect to see it on your timeslip.
Why:
1. Small mean radius of gyration = low moment of inertia (compared to a clutch disc, converter or ring gear)
2. Low RPM through almost all the race (compared to anything in front of the transmission)
Why:
1. Small mean radius of gyration = low moment of inertia (compared to a clutch disc, converter or ring gear)
2. Low RPM through almost all the race (compared to anything in front of the transmission)
Posted By: Quicktree
Re: Aluminum vs Steel Replacement Driveshaft Question - 11/14/09 03:12 PM
I have their aluminum shaft, saves a few pounds of spinning mass. I would buy another one. great product and custmer service 
Posted By: Cab_Burge
Re: Aluminum vs Steel Replacement Driveshaft Question - 11/14/09 04:47 PM
Quote:It depends on what your doing with the car, if you want it to be as fast as posible I have seen many NHRA class cars pick up MPH and reduce ET by using a lighter driveshaft than a heavier one on back to back test
I am going to order a new driveshaft Monday from Dynotech and wondering is there any advantage in going with an aluminum one over a steel replacement?
A 10 lb. difference in weight loss makes more gain than a 5 lb loss (reduction) does 
Posted By: SCATPK
Re: Aluminum vs Steel Replacement Driveshaft Question - 11/14/09 04:50 PM
Sounds like I should stick with a steel replacment one. I was told that the diameter will need to increase by .050 going with aluminum over the stock piece. Any other suggestions as I have the measurments and will be placing a call first thing Monday morning.
Posted By: jcc
Re: Aluminum vs Steel Replacement Driveshaft Question - 11/14/09 07:18 PM
I would also assum an alum driveshaft would do less damage then a steel one upon a driveshaft failure, with or without a loop, and CF doing the least damage.
Posted By: Anonymous
Re: Aluminum vs Steel Replacement Driveshaft Question - 11/14/09 08:13 PM
I went with a mark williams aluminum driveshaft with 1350 yokes on both ends and it was a smart choice. picked up a little, MW has great customer service and i'd buy another one in a heartbeat.
i like the light weight over the steel shaft.
i like the light weight over the steel shaft.
Posted By: autoxcuda
Re: Aluminum vs Steel Replacement Driveshaft Question - 11/14/09 08:26 PM
Does a lighter driveshaft balance better and give off less harmonics at cruising. Like it could be quieter.
I see aluminum used is OE cars and I doubt it's just for weight. I see short cars like new mustangs with split double driveshafts. I assume thats for noise and vibration??
I see aluminum used is OE cars and I doubt it's just for weight. I see short cars like new mustangs with split double driveshafts. I assume thats for noise and vibration??
Posted By: jcc
Re: Aluminum vs Steel Replacement Driveshaft Question - 11/14/09 09:09 PM
Quote:
Does a lighter driveshaft balance better and give off less harmonics at cruising. Like it could be quieter.
Since alum usually requires a larger(next) diameter, it likely would be stiffer and therefore less harmonics, etc or they would be a higher freq.
One of my cars has a MW bonded alum/1350, which I like, I asked them years ago about lightweight foam filling an alum bonded driveshaft, they just gave a funny look.
Posted By: SCATPK
Re: Aluminum vs Steel Replacement Driveshaft Question - 11/14/09 10:43 PM
Sounds like the aluminum unit may be just a tick lighter but also opens up potential clearance issues with exhaust. Any other pro or cons with one or the other. I figure I am going to spend the money and want to make a smart choice.
Posted By: polyspheric
Re: Aluminum vs Steel Replacement Driveshaft Question *DELETED* - 11/14/09 10:57 PM
Post deleted by polyspheric
Posted By: Quicktree
Re: Aluminum vs Steel Replacement Driveshaft Question - 11/15/09 12:15 AM
Quote:
Since alum usually requires a larger(next) diameter, it likely would be stiffer
No, aluminum is far less stiff than steel and needs the diameter to even be comparable; more wall thickness makes up the remaining difference.
my 3.5" aluminum shaft is rated to over 1000hp
Posted By: 408Dust
Re: Aluminum vs Steel Replacement Driveshaft Question - 11/15/09 12:27 AM
Critical speed is the deciding factor in drive shaft material selection. Aluminum increases your critical speed rating, there is no real performance advantage to it other then raising the critical speed rating.Call Mark Williams, PST etc and give them your drive shaft length and maximum RPM at the stripe and see what they say.