Steel VS Aluminum Driveshaft [Archive] - Chevelle Tech

: Steel VS Aluminum Driveshaft


Strokd66
Jun 2nd, 11, 10:11 AM
Is there anything to be gained possiably in the 60ft or overall at the track when going from a steel to aluminum driveshaft?

engineguy
Jun 2nd, 11, 10:30 AM
Aluminum driveshaft does have advantages over a steel one, but just changing to an aluminum 'shaft won't make a "noticable difference" in your 60 ft. times - in my opinion.

jeff swisher
Jun 2nd, 11, 10:44 AM
I know one instance where it made a huge difference in seat of the pants,
this was in a fox body mustang.
I have asked the guys at Drive train specialists here in OKC. and they told me that i should stick with my steel shaft, reason being ,, they get a lot of aluminum in there with the ears twisted off...and just as he said that a guy walks in with an aluminum shaft with the ears twisted off.
I set my transmission yolk on the counter and told him to build me my same old steel shaft...
I hammer my stuff pretty hard and there is always a lot of "off road" stuff with loading and unloading of the shaft..maybe the aluminum ends they have just aint up to the task...it is a mystery

blumont
Jun 2nd, 11, 11:12 AM
Denny's would not sell me an aluminum drive shaft, they said it should be steel.

bracketchev1221
Jun 2nd, 11, 11:41 AM
Unless you need one for Metallurgic issues, I would not get one. Steel is fine. My car, needed one based on the critical speed of the shaft. For the length and rpm it would see, a steel shaft would bow and create a jump rope under the car.

Strokd66
Jun 2nd, 11, 11:46 AM
OK I'll stick with the steel....

big_orange
Jun 2nd, 11, 12:04 PM
I know one instance where it made a huge difference in seat of the pants,
this was in a fox body mustang.


thats because most of em dont have enough power to turn a steel shaftl:)

ripdog28
Jun 2nd, 11, 12:39 PM
I actually run a Alum, any one run one that didnt like it who has posted so far? or just what you heard? I did my research and called tech lines. Inland Empire Driveline was one of the first to be certified by NHRA/IMCA for their alum shafts. They currently have them in 2k+ hp cars with out a single problem. Benefits, Less drag on engine to turn, faster revs, more power to wheels, easier to balance, overall lighter. Im pushing close to 600hp/tq in a nearly 3800lb truck and so far not one problem. I have turned 6k+, long nasty burn outs from a dead stop and rolling and the general beating. From day one i beat on this. I didnt properly tq a u-joint and it fell apart on one of my abusive rides and only thing that happened when the shaft smacked the driveshaft hoop was a few small dents. Called them up, told them what i did and they fixed it at a discount. I love this site but a lot of guys talk about what they hear with no personal experience, even i have. Call someone who does it right and has experience, Inland Empire Driveline is backed by their tried and trued alum shafts. A lot of companies are recently getting into the alum shaft business, IEDLS has been in it for a while. and their u-joint ears are thick as hell.

CDN SS
Jun 2nd, 11, 1:14 PM
FWIW I have a Dennys 4" Alum ....Nitrous Series I think its called ......been in car since 2006 ..........not raced every weekend but defintley gets a workout with stik car with slicks and 5k launces ......no issues no vibrations etc

jeff swisher
Jun 2nd, 11, 4:17 PM
I figured someone was making a good aluminum..that is why i posted :..maybe the aluminum ends they have just aint up to the task...it is a mystery ..
Now i know where to go if i get the desire to try the aluminum,,, i have seen some nice looking carbon shafts..but really never researched them. I do think i remember reading they have even better harmonic reducing capability than aluminum...that is as far as my research went

And the ford Fox body had the 347 and gt40 heads and x303 or b303 cam and the aluminum shaft made more difference than the cam change..in seat of the pants...but Big_orange you are right just a 12 second light ford car,,,not impresive for all the money and addons

novaderrik
Jun 2nd, 11, 5:42 PM
my only experience with swapping in an aluminum shaft was in a friend's 95 Z/28. another friend worked at a GM dealer and they had an aluminum shaft out of a 6 speed car that he got for free. just putting that in the car made a noticeable difference in how the car felt off the line. if it worked that well in a car with a 3 foot long driveshaft, i think it would do even more in a car with a 5 foot long driveshaft.

Greg Owens
Jun 2nd, 11, 5:51 PM
Not trying to call out those that have said otherwise, but a driveshaft change alone is not going to give you a change in power. "Seat of the pants" is worth nothing in my book. Too many variables. It takes a dyno or a time slip IMHO. You feel a seat of the pants change if you WANT to feel one (to justify the expenditure??). In fact, a drive shaft change is not going to give a time slip measurable difference either. The difference in weight is minimal, and the weight is so close to the center line of rotation that it's not going to make any difference.

Now there may have been some other issues going on that happened to get worked out when swapping the drive shaft, but I'd hate for a bunch of folks to read that post and go spend their hard earned money on an aluminum drive shaft thinking it's going to make the car faster.

68rat454
Jun 2nd, 11, 6:01 PM
To further support Greg on this--- I changed the car last year from CM steel to carbon fiber and saw ZERO change on the time slips...

I changed shafts because I had to change the length and decided on carbon fiber in case it breaks and how well they disintegrate and possibly save some parts under the car.

bracketchev1221
Jun 2nd, 11, 10:44 PM
I never said aluminum was bad, just didn't see the need to get one. I have been running mine for 8 years. No issues going mid 1.20's in 60 ft at almost 3200 lbs. If Mark Williams would have LET me buy a chromoly shaft for my car, that is what would have been in there. My friend has a chromoly MW driveshaft in his 3500 lbs 1000hp 70 El Camino. When I got mine, the high speed spin equipment had just come out, and MW said if they had it when my friend ordered his, a chromoly shaft would have NEVER been sold for his car.

Bob West
Jun 2nd, 11, 10:50 PM
I believe Ed used to say his aluminum driveshaft was worth .04 in e.t. I still run steel with Spicer 1310 u joints :)

bigmachd
Jun 2nd, 11, 11:52 PM
Did Jeff say the "F" word?

jeff swisher
Jun 3rd, 11, 1:51 AM
Yes the F word came out..sorry something must be done to them fomoco's to get every last ounce of power from them...The buttometer of mine is pretty touchy...I can actually tell if i went .1 second quicker through the 1/4 ..you know when everything lines up..possibly the hundreds and hundreds of passes down the 1/4...
I would not just buy one unless there is solid proof that your car will need one.. in fact i am not sold on aluminum at all...Never ran the stang down the track,,just street with buddies and it did put some extra distance between a couple of them...could have been the stocker P.O.S. was out of ballance
Had a chevy shaft that was out of ballance did not know with 308 gears.
but when i put in my 456's i could hit 7500rpm in first and second then she would flat stall at 6000 rpm in 3rd..(th350)..would not rev any higher..

I scratched my head for a few days.broke another u joint then had a bigger diameter shaft built.
It reved to 7500 in 3rd..then i had them check the stock shaft..as i put new joints in it,,spare you know.. yep out of ballance.....put it in after the ballance and she went 7500 in all 3
it never did change anything comming out of the hole though

engineguy
Jun 3rd, 11, 10:05 AM
Choosing a driveshaft is relatively simple:
- 3.0" mild steel is best choice for most high performance street driven vehicles.
- upgrade to 3.5" or 4.0" mild steel for increases in critical speed.
- upgrade to 3.5" or 4.0" 6061 aluminum for further increased in critical speed.
- Carbon fiber for the ultimate in critical speed.

Any driveshaft upgrade should include at least 4340 forged transmission and pinion yokes with 1350 series u-joints.
Critial speed is a function of driveshaft max RPM and shaft length. (Mark Williams catalog is an excellent reference for determining driveshaft material limitations, based on RPM and length.)

elcaminodragster
Jun 3rd, 11, 11:35 AM
thats because most of em dont have enough power to turn a steel shaftl:)

HAHAHAHAHA thats awesome!!!!



I bought a 4" aluminum with 1350 joints and my trans is not smooth at all it tries to break your neck every shift so the driveshaft really gets a beating!

From what I ve read on here and many other sites talking to companies the ds has to be built for your car. but the basics are simple

Steel transfers shock from shifts to the rear end
Aluminum absorbs the initial hit softening the blow to the rear.

Steel twists 5-7* (IIRC)
Aluminum twists 15-17* (IIRC)
Which is what softensthe blow to the rear end

Steel will turn into a "jump rope" at the end of the track
Aluminum does not.
But that also depends onthe wall thickness of the steel

Steel will cause vibration no matter how well it is balanced its the nature of the beast
Aluminum absorbs vibration.

This may seem like im saying aluminum is way better but its not! Aluminum belongs in onecar and steel in the other it just depends on what your doing plan and simple

The whole ears twisting off is bs because everytime I hear that and see the shaft its because there wasnt enough meat on the ears or the driver did something wrong to cause the failure.

Here is a pic of my old steel shaft with 1310 joints compared to my aluminum with 1350 joints

http://i959.photobucket.com/albums/ae74/elcaminodragster/Frankenstein/Suspension%20and%20Driveline/Newaluminumdriveshaft4.jpg

Strokd66
Jun 3rd, 11, 11:43 AM
The reason I started this post was to see if it was beneficial to get an aluminum shaft out of a junkyard that is the same length as my steel one. It appears that a stock 4" aluminum shaft wont be as strong as my steel one?

rkd
Jun 3rd, 11, 12:57 PM
I changed from a previously balanced stock steel driveshaft on my hotrod, to the "manufacturers racing performance parts" aluminum one. I did not notice any et gain, but it was a whole lot smoother/less vibration. The car is silky smooth at 70 on the highway with 4.10 or 4.56 gears (no o/d) and at 100+ at the track. Yes, this is for my slow, 200 hp, 302 powered 12 second toy that needs all the help it can get. If it gets a second quicker, I may relook the d/s issue. But for now, its perfect, and for less than all out racing, I would recommend it. The critical speed calculation does need to be reviewed.

My Chevelle has a brand new steel shaft, made with my original ends, also balanced, with no issues. It also seems well balanced at highway speeds. The custom rebuild took a half day, and only cost $165 locally.

crazydavey
Jun 3rd, 11, 3:23 PM
Jeff the real issue is critical speed. Get one that meets your max RPM needs plus whatever you want to grow into...from there it's just how much do you want to spend....

and my steel driveshaft has never had any vibration issues...

dtrubey
Jun 3rd, 11, 4:40 PM
Yeah Dave, you lived that one first hand. Your car didn't fair quite as well as you did, luckily. Like we've been talking, 2 shops told me my 3 1/2" steel shaft at 55 1/2" and 6,300 rpm is on the ragged edge of being a jump rope.
Is it bad to buy parts instead of food?

crazydavey
Jun 3rd, 11, 5:04 PM
Yeah Dave, you lived that one first hand. Your car didn't fair quite as well as you did, luckily. Like we've been talking, 2 shops told me my 3 1/2" steel shaft at 55 1/2" and 6,300 rpm is on the ragged edge of being a jump rope.
Is it bad to buy parts instead of food?

not if you have your priorities right....;)

dtrubey
Jun 3rd, 11, 5:12 PM
My wife said something about wanting your wife's cell phone number.
Crap......we better start burning receipts. Gotta match?

GRN69CHV
Jun 3rd, 11, 5:35 PM
Ironic this thread came about. Crawled under the car last night to install a UMI safety loop. Rear joint was noteably very stiff. Pulled the shaft and dropped it off to get looked at this morning. This is a stock shaft that was in very good shape with nothing more that new 1310 joints , 6-7 years ago, maybe 5,000-6,000 miles in that time period. Had a noted vibration at 70-75 in the mirror on the highway. Complete blur in all the mirrors going through the traps 115-117 where the car ran. Critical speed for a 3"'shaft in a '69 is 5900 rpm, which surprisingly , with a 28" tire and 4.10 gears is easily exceeded at about 120 mph (tossed my notes, but this is close). Dropping to a 3.42 gear , driveshaft rpm drops to 5000 +/- at 120-123. Big difference. Assuming 66-67 cars use a longer drive shaft due to the longer wheelbase. Chart I found lists 500 rpm change for every 4" driveshaft length. In Davey's case, you can clearly see, just based on the numbers how a stock type shaft could quickly become a time bomb as you add in mph, gearing and shaft length.

dtrubey
Jun 3rd, 11, 5:46 PM
Here's the MW chart. Anyone else had any bad experiences?

GRN69CHV
Jun 3rd, 11, 6:09 PM
That chart lists lower critical speeds than the chart I saw. 55.5" length (thought 69-70 is 54.5"??) with 4.10's running in the 120's, looks like there's not much of a safety margin.

dtrubey
Jun 3rd, 11, 6:54 PM
I have a 9" so it even longer and the car is going faster than I ever expected. I wasn't planning on another new driveshaft. Looks like a 4" aluminum is the only thing left. Carbon fiber is out.

andrewb70
Jun 3rd, 11, 11:05 PM
Since the subject of vibration came up in this thread, I thought you al might be interested in this:

http://www.chevelles.com/forums/showthread.php?t=353010

Andrew

Steve439
Jun 3rd, 11, 11:21 PM
Ironic this thread came about. Crawled under the car last night to install a UMI safety loop. Rear joint was noteably very stiff. Pulled the shaft and dropped it off to get looked at this morning. This is a stock shaft that was in very good shape with nothing more that new 1310 joints , 6-7 years ago, maybe 5,000-6,000 miles in that time period. Had a noted vibration at 70-75 in the mirror on the highway. Complete blur in all the mirrors going through the traps 115-117 where the car ran. Critical speed for a 3"'shaft in a '69 is 5900 rpm, which surprisingly , with a 28" tire and 4.10 gears is easily exceeded at about 120 mph (tossed my notes, but this is close). Dropping to a 3.42 gear , driveshaft rpm drops to 5000 +/- at 120-123. Big difference. Assuming 66-67 cars use a longer drive shaft due to the longer wheelbase. Chart I found lists 500 rpm change for every 4" driveshaft length. In Davey's case, you can clearly see, just based on the numbers how a stock type shaft could quickly become a time bomb as you add in mph, gearing and shaft length.

It's great to hear you're crawling around under your car and swapping drive shafts.

It's also nice to hear guys are running 1310s with more torque than I have!
I have a 1310/1330 conversion up front and that one worries me...

Bob West
Jun 3rd, 11, 11:30 PM
1310's are solid, no zerk fittings. The zerk is the weak spot ;)

Steve439
Jun 4th, 11, 12:51 AM
1310's are solid, no zerk fittings. The zerk is the weak spot ;)

I'm still way impressed the solid 1310s hold up to those launches.

The 1310/1330 conversions are a real pisser.
AFAIK Spicer doesn't make a solid one.

engineguy
Jun 4th, 11, 9:06 AM
Virtually ANYTHING that rotates has a critical speed. In the case of driveshafts, the critical speed is a function of length, diameter, wall thickness and materials. Once critical speed is reached, it is possible for any driveshaft, whether it is steel, aluminum or carbon fiber to swirl (go into jumprope shape). Even turbocharger impeller shafts have critical speeds, although it is quite high due to their short length and small diameter. Typical turbo impellers may attain RPM as high as 200,000 to 300,000 RPM. OK, sorry - I realize that we have gotten off the original topic.

Strokd66
Jun 4th, 11, 9:47 AM
1310's are solid, no zerk fittings. The zerk is the weak spot ;)

thats what i run