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Aluminum Driveshaft?

Posted By: RylisPro

Aluminum Driveshaft? - 07/11/13 03:29 AM

Any of you guys that road race use an aluminum driveshaft? I am getting a new steel one made and it's only $100 more for aluminum one. Wondering if it was worth it for the weight savings? Any opinions, pros and cons of steel vs. aluminum?

thanks
Posted By: ahy

Re: Aluminum Driveshaft? - 07/11/13 04:23 AM

Opinion... I thing the biggest benefit of aluminum is to protect a fragile rear with drag starts. Not a factor with RR. Unless there is a major weight savings I'd go steel for strength and fatigue resistance.
Posted By: 72Swinger

Re: Aluminum Driveshaft? - 07/11/13 05:06 AM

I run a 3.5" AL shaft. My thinking was stability at high shaft speed. The jury is still out on that. The OEM's are using them behind Diesel engines and everything else too.

Attached picture 7772632-020.JPG
Posted By: AndyF

Re: Aluminum Driveshaft? - 07/11/13 05:12 AM

We put an aluminum driveshaft in Tim's Valiant last time it was upgraded. Pretty much needed the aluminum in order to keep the weight reasonable. At 160 mph the driveshaft speed is starting to get high enough that we needed the larger shaft diameter. A large diameter shaft gets heavy if it is steel.
Posted By: dart4forte

Re: Aluminum Driveshaft? - 07/11/13 06:10 AM

Quote:

We put an aluminum driveshaft in Tim's Valiant last time it was upgraded. Pretty much needed the aluminum in order to keep the weight reasonable. At 160 mph the driveshaft speed is starting to get high enough that we needed the larger shaft diameter. A large diameter shaft gets heavy if it is steel.



Bonneville car?
Posted By: autoxcuda

Re: Aluminum Driveshaft? - 07/11/13 06:29 AM

Quote:

We put an aluminum driveshaft in Tim's Valiant last time it was upgraded. Pretty much needed the aluminum in order to keep the weight reasonable. At 160 mph the driveshaft speed is starting to get high enough that we needed the larger shaft diameter. A large diameter shaft gets heavy if it is steel.



What was the diameter and wall thickness? What U-joints did you use?
Posted By: BigBlockMopar

Re: Aluminum Driveshaft? - 07/11/13 08:17 AM

Quote:

Opinion... I thing the biggest benefit of aluminum is to protect a fragile rear with drag starts. Not a factor with RR. Unless there is a major weight savings I'd go steel for strength and fatigue resistance.




I beg to differ on the first part. It simply takes less power to rotate a lighter weight part than a heavyweight part.
Since a dragrace is one long acceleration and increase in RPM of the driveshaft, there are benefits.

I also think it would benefit a roadracer since car and driveshaft speeds are constantly changing during the race.
Posted By: Mopar Mitch

Re: Aluminum Driveshaft? - 07/11/13 03:46 PM

Lighter weight = faster acceleration, quicker deceleration, even overall better g-force in the corners... simply, physics (less weight is always better, as long as the strength for critical components is not sacrificed (i.e safety).
Posted By: BergmanAutoCraft

Re: Aluminum Driveshaft? - 07/11/13 04:03 PM

I think one of the most important things is who's making it. I've seen runout on too many custom driveshafts. I run and sell Dynotech shafts. Mine is 3.5 Alum with 1350 joints. Runout under .010. Very smooth at speeds up 130 so far.
Posted By: MuuMuu101

Re: Aluminum Driveshaft? - 07/11/13 04:59 PM

Quote:

Quote:

Opinion... I thing the biggest benefit of aluminum is to protect a fragile rear with drag starts. Not a factor with RR. Unless there is a major weight savings I'd go steel for strength and fatigue resistance.




I beg to differ on the first part. It simply takes less power to rotate a lighter weight part than a heavyweight part.
Since a dragrace is one long acceleration and increase in RPM of the driveshaft, there are benefits.

I also think it would benefit a roadracer since car and driveshaft speeds are constantly changing during the race.



It's all rotating mass and moments of inertia. The larger MOI you have, the more the shaft is going to want to resist rotating. The lighter mass and the closer it is to the center of rotation, the better.
Posted By: AndyF

Re: Aluminum Driveshaft? - 07/11/13 06:06 PM

Quote:

Quote:

We put an aluminum driveshaft in Tim's Valiant last time it was upgraded. Pretty much needed the aluminum in order to keep the weight reasonable. At 160 mph the driveshaft speed is starting to get high enough that we needed the larger shaft diameter. A large diameter shaft gets heavy if it is steel.



Bonneville car?



Road race car. 1968 Valiant. Couple of articles in Mopar Muscle show the build.
Posted By: RylisPro

Re: Aluminum Driveshaft? - 07/11/13 06:43 PM

Thanks for all the advice, I think I will go aluminum

My biggest concern would be denting the aluminum driveshaft if and when I go off track, hopefully my exhaust system will help shield it from any damage.
Which aluminum driveshaft vendor did you guys buy from or recommend?

thanks
Posted By: 72Swinger

Re: Aluminum Driveshaft? - 07/11/13 08:48 PM

Mine is made from 3.5" OD x .125 DOM FYI. http://www.actionmachineinc.com/aluminumdriveshaft.aspx
Posted By: autoxcuda

Re: Aluminum Driveshaft? - 07/11/13 09:29 PM

Quote:

Thanks for all the advice, I think I will go aluminum

My biggest concern would be denting the aluminum driveshaft if and when I go off track, hopefully my exhaust system will help shield it from any damage.




Steel ones dent too. I wouldn't worry about it.

Quote:

Which aluminum driveshaft vendor did you guys buy from or recommend?

thanks
..



They are not brain surgery. Most stock cars have them now. Just find a local driveshaft shop that the local hot rods and racer guys all go to a respect.
Posted By: Challenger 1

Re: Aluminum Driveshaft? - 07/12/13 12:09 AM

I had this one made here in town at the local "driveline" shop.

I remember it was not much more $$ than steel so I said WTF make it out of aluminum last time I needed a drive shaft.

The only thing I wanted to point in my case the diameter is bigger than my stock steel shaft. It fit but is real close to my mufflers but does not hit them.
It has held up in my 500hp car.


I weighed it, it was much lighter, don't remember the numbers.
Posted By: Darryls-Demon

Re: Aluminum Driveshaft? - 07/12/13 04:34 AM

I picked up a brand new aluminum drive shaft with new 1350 u joints that was out of a ford van, found it on Craigslist for 50 bucks.
Posted By: jrlegacy23

Re: Aluminum Driveshaft? - 07/12/13 04:27 PM

Quote:

I picked up a brand new aluminum drive shaft with new 1350 u joints that was out of a ford van, found it on Craigslist for 50 bucks.



I pulled mine out of an old crown vic cop car, also 1350 joints.

Quote:

Thanks for all the advice, I think I will go aluminum

My biggest concern would be denting the aluminum driveshaft if and when I go off track, hopefully my exhaust system will help shield it from any damage.
Which aluminum driveshaft vendor did you guys buy from or recommend?

thanks



Aluminum has a memory, if you bend it a little, it will go back on its own. It may be softer than steel, but will less likely dent as easily.
Posted By: AlexP

Re: Aluminum Driveshaft? - 07/12/13 09:24 PM

How long are the typical ford crown vic and van driveshafts?
Posted By: jrlegacy23

Re: Aluminum Driveshaft? - 07/13/13 12:53 AM

Quote:

How long are the typical ford crown vic and van driveshafts?



I don't remember the overall length, but I moved my rear end back 1.25" and still had to cut around 1 5/8" out of the shaft.
Posted By: 71autoxr

Re: Aluminum Driveshaft? - 07/13/13 03:25 AM

I guess I'm a little late to the party. I have a 71 Challenger small block and when it came time for a drive-shaft I opted for aluminum. Had mine built by Denny's Drive shaft they were running a special and the aluminum was not much more than steel. I autocrossed the car for years, and have done a reasonable amount of road racing. Took the car off track in the dirt at Willow Springs, no damage to the drive shaft. You can probably have one built locally and save the shipping.
Posted By: Mopar Mitch

Re: Aluminum Driveshaft? - 07/13/13 05:34 AM

anybody know the weight savings difference (Challenger)?
Posted By: MuuMuu101

Re: Aluminum Driveshaft? - 07/13/13 04:59 PM

Quote:

anybody know the weight savings difference (Challenger)?



If someone doesn't have the actual weights on hand I can try to model them on Solidworks during the week (I need the practice ). I'd just need all the primary dimensions (length, tube OD, tube thickness, misc joint connections). After I model the two I can check the mass properties and it will tell me approximate weight and the moments of inertia exerted by both so you can see how much more/less the aluminum shaft resists rotation compared to the steel one.
Posted By: 71autoxr

Re: Aluminum Driveshaft? - 07/13/13 06:20 PM

Quote:

anybody know the weight savings difference (Challenger)?


Mitch i didnt weigh mine when i did it, i needed a new one out of necessity.
Posted By: Mattax

Re: Aluminum Driveshaft? - 07/13/13 08:11 PM

Vizzard did some testing that he wrote up in one of the popular mags, probably PHR. My recollection is that he didn't find any measurable gains in drivetrain components like the driveshaft.
For overall weight, of course its worth something.

FWIW the folks at Empire (I think thats the name) disuaded me from using al. because it would be subject to rapid reverses in load (high rpm engine braking in first & 2nd). With no safety loop, I wanted to take no extra chances for such small potential gain.
Posted By: DAYCLONA

Re: Aluminum Driveshaft? - 07/13/13 10:12 PM

Quote:

anybody know the weight savings difference






An Aluminum shaft's approx. weight, (shafts only) verses that of the same size (length) shaft in steel is approx 30% lighter, a carbon fiber shaft is approx 50% lighter than the same size (length) shaft in steel...so if you know your current steel shaft's weight, it's simple arithmetic to find the proposed weight of it's aluminum or Carbon fiber counterpart

Aluminum shafts will generally have up to a 25% larger O.D. increase in the tubing size to maintain the torsional properties of the steel counterpart it's replacing
Posted By: DAYCLONA

Re: Aluminum Driveshaft? - 07/13/13 10:34 PM

Quote:

Vizzard did some testing that he wrote up in one of the popular mags, probably PHR. My recollection is that he didn't find any measurable gains in drivetrain components like the driveshaft.
For overall weight, of course its worth something.






There was a recent Dyno test done, although it was a brand X, A shootout of steel vs aluminum vs carbon fiber shafts mounted in the same test vehicle, the dyno end results were a 1% increase in HP using the aluminum shaft, and a 5% HP increase using the Carbon Fiber shaft vs the original steel shaft,...while there are some "measurable" increases to be found there are also some physical (use) limitations in lighter/alternate material shaft applications
Posted By: Supercuda

Re: Aluminum Driveshaft? - 07/13/13 11:01 PM

Dyno tests are steady state conditions. You are not going to see any HP change in regards to drive shaft materials, 1% is margin of error wishful thinking and I seriously doubt the 5% claim for CF.

Where you may see it is in acceleration times, but mostly likely not even then as the difference is not all that great.
Posted By: jcc

Re: Aluminum Driveshaft? - 07/13/13 11:12 PM

Quote:



FWIW the folks at Empire (I think thats the name) disuaded me from using al. because it would be subject to rapid reverses in load (high rpm engine braking in first & 2nd). With no safety loop, I wanted to take no extra chances..



IMO, technically any stress reversals ARE best avoided with alum, however, how many hard downshifts/engine braking events are we actually talking about? In the tens of 1,000's? And i would rather have an alum driveshaft fail then a steel one without a loop. And most importantly IMO, hard downshifts/engine braking is so 60's
Posted By: Skeptic

Re: Aluminum Driveshaft? - 07/14/13 12:48 AM

Quote:

anybody know the weight savings difference (Challenger)?

According to the Denny's site linked before "about 6 lbs"
Posted By: Mattax

Re: Aluminum Driveshaft? - 07/14/13 03:16 AM

"And i would rather have an alum driveshaft fail then a steel one without a loop."
In my book, driveshaft failures are just bad news. Right up there with tranmissions exploding, maybe even worse. Everyone has their own risk/reward tipping point. Everyone makes their own choices. I respect that.

"And most importantly IMO, hard downshifts/engine braking is so 60's "
Downshifting? downshifting? Heck, I just put in first or second and leave it there.
All readers are supposed remember or know through mind reading that I autocross the car.;)
Posted By: dodgeboy11

Re: Aluminum Driveshaft? - 07/15/13 12:02 AM

Quote:

I guess I'm a little late to the party. I have a 71 Challenger small block and when it came time for a drive-shaft I opted for aluminum. Had mine built by Denny's Drive shaft they were running a special and the aluminum was not much more than steel. I autocrossed the car for years, and have done a reasonable amount of road racing. Took the car off track in the dirt at Willow Springs, no damage to the drive shaft. You can probably have one built locally and save the shipping.



I have to give props to Dennys Drive Shaft. Contacted them for a driveline for my truck, they told me what to measure and how, I told them I wanted a CV at the front (lifted 4x4) of the rear driveline and they sent the proper yoke and a driveline that bolted into the truck and hasn't given me any trouble since. Haven't even needed to replace any u-joints as I opted for the sealed joints. Now I know that wasn't an answer to the OP, but if you're looking for a place to buy one, I recommend Denny's.
Posted By: RylisPro

Re: Aluminum Driveshaft? - 07/15/13 12:48 AM

Anybody have any luck with PST driveshafts in Florida? http://www.pstds.com
I got my T56 Magnum kit from American Powertrain and they have a deal with them and sources all their new driveshafts from there, way cheaper than going with another vendor.
I'm just hoping they make a good product
Posted By: DAYCLONA

Re: Aluminum Driveshaft? - 07/15/13 01:37 AM

Quote:

Anybody have any luck with PST driveshafts in Florida? http://www.pstds.com
I got my T56 Magnum kit from American Powertrain and they have a deal with them and sources all their new driveshafts from there, way cheaper than going with another vendor.
I'm just hoping they make a good product







Talk to Grey Fredricks at American PowerTrain he'll steer you in the right direction for a driveshaft vendor

Mike
Posted By: blown340

Re: Aluminum Driveshaft? - 07/20/13 12:37 AM

Quote:

Anybody have any luck with PST driveshafts in Florida? http://www.pstds.com
I got my T56 Magnum kit from American Powertrain and they have a deal with them and sources all their new driveshafts from there, way cheaper than going with another vendor.
I'm just hoping they make a good product




Where in Norcal are you? I've had custom stuff made by Driveline Service of Concord in the bay area. My parts were excellent and the price was cheaper than any of the mail order stuff.

-Jon
Posted By: RylisPro

Re: Aluminum Driveshaft? - 07/20/13 12:46 AM

I'm in Concord.
Since I bought a T56 Magnum kit from American Powertrain who has a deal with PST driveshafts, my driveshaft is going to end up to be $100-150 bucks.
$100 more if I want to go aluminum. I will also be upgrading to Spicer yokes and 1350 u-joints so not a bad deal.
My installer has a PST driveshaft and he says they are good so I will go with them
Posted By: AndyF

Re: Aluminum Driveshaft? - 07/20/13 02:29 AM

Quote:

Quote:

We put an aluminum driveshaft in Tim's Valiant last time it was upgraded. Pretty much needed the aluminum in order to keep the weight reasonable. At 160 mph the driveshaft speed is starting to get high enough that we needed the larger shaft diameter. A large diameter shaft gets heavy if it is steel.



What was the diameter and wall thickness? What U-joints did you use?



3.5 inch OD, not sure on the thickness. 1350 u-joints. No reason to cut any corners when you have 427 cubic inches of road race engine up front.
Posted By: autoxcuda

Re: Aluminum Driveshaft? - 07/20/13 04:24 AM

Quote:

I'm in Concord.
Since I bought a T56 Magnum kit from American Powertrain who has a deal with PST driveshafts, my driveshaft is going to end up to be $100-150 bucks.
$100 more if I want to go aluminum. I will also be upgrading to Spicer yokes and 1350 u-joints so not a bad deal.
My installer has a PST driveshaft and he says they are good so I will go with them




Why not deal with a reputable local source you can deal with eye to eye? At least check them out and get a price. You will build a customer relationship for all future work.

No shipping cost, no possibility shipping damage, loss or theft...

The grass is not always greener because someone advertises in magazines and had a great website built for them.
Posted By: autoxcuda

Re: Aluminum Driveshaft? - 07/20/13 04:31 AM

Quote:

Quote:

Quote:

We put an aluminum driveshaft in Tim's Valiant last time it was upgraded. Pretty much needed the aluminum in order to keep the weight reasonable. At 160 mph the driveshaft speed is starting to get high enough that we needed the larger shaft diameter. A large diameter shaft gets heavy if it is steel.



What was the diameter and wall thickness? What U-joints did you use?



3.5 inch OD, not sure on the thickness. 1350 u-joints. No reason to cut any corners when you have 427 cubic inches of road race engine up front.



Thanks. A new driveshaft is in the future for me. My original one took a lot of straightening.

Heated in 3-4 places and looks like a slot machine threw up on both ends of it. Poor driveshaft place couldn't have made any money on my flat fee $45 balance job.

Made a HUGE improvement. Now I can see actually see out of my rear view mirror drive 75 mph (~3700 rpm) or over.
Posted By: AndyF

Re: Aluminum Driveshaft? - 07/20/13 05:24 AM

A 3.5 inch driveshaft chews up a lot of space in an A-body tunnel. Probably better to stick with a 3 inch steel one if you can. Just have to run the numbers and see. Depends on max driveshaft speed and power level.
Posted By: autoxcuda

Re: Aluminum Driveshaft? - 07/20/13 06:12 AM

Quote:

A 3.5 inch driveshaft chews up a lot of space in an A-body tunnel. Probably better to stick with a 3 inch steel one if you can. Just have to run the numbers and see. Depends on max driveshaft speed and power level.



Very good point. I have TTI headers with TTI X-pipe in 2.5" diameter pipe.

I'm probably at 450 HP with a 419 stroker and I plan to run the same size tires that Tim W runs (275/40/17). Currently have 3.23 gears. I'm about 6000 rpm at the end of the big straight. And that's with poor brakes, tires, and lots of room for driver improvement.

But I think that is too much at the big Willow Springs track and 2.94's like Tim W has would be better.
Posted By: jcc

Re: Aluminum Driveshaft? - 07/20/13 05:16 PM

Quote:

I'm about 6000 rpm at the end of the big straight.



Bigger spoilers F/R will solve that also.
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